They Just Can't Help Themselves
The peas can't even discuss the happenings of this blog with out fighting with themselves. This is such a mean and hurtful place and yet many of them can not see that 2 peas has been mean and hurtful to many people as well. Those people who can't see that, are the peas that head the board and have their little cliques. The peas who have friends that will jump to their defense and in some cases do the dirty work of cutting others down when someone in their group has been threatened. I don't think some of them will ever see clearly.
posted by 2 peas in my ass @ 9:56 AM
102 comments
102 Comments:
"Those people who can't see that are the peas that head the board and have their little cliques."
HUH? Am I sleep deprived or does this sentence make no sense.
can we discuss the seemingly endless threads that minzy puts up asking about baby names?
ALL THAT TIME FOR THAT SHIT ABOUT CONSTIPATION...
JESUS CHRIST BIOTCH,.. WTF! IS YOUR PROBLEM.. LET ME GUESS, BLOGGER HIT A SOFT SPOT AND YOUR A LITTLE TESTY.. GET A LIFE YOU PSYCHO!
OK, um thanks for the constipation thing again. I'm beginning to think I need to come up with an anon at 2Peas and start copying and pasting that there.
You might not like this blog (whoever is doing that) but some of us have been pushed out of peas because of the cliques. Some of us aren't leaving nasty comments here.
I have to agree with the blogger on this entry.
Let one of them honestly disagree with Seanna, Monique, Molove, or one like them and see how fast the pile-on starts.
There are people who freely admit they would gang up on someone in defense of a friend on the boards even if the friend was in the wrong. It's disgusting.
You know what I fumd funnier than hell about this is...
The 2peas dumbasses who are always preaching to use the ignore button on people can't even figure out how to ignore what goes onhere. If they weren't so damn nosey and righteous all the time, they wouldn't even know what was being said here. Now the stupid bitches are arguing amongst themselves over who has been pissedon the most and who defended who. Hell, this blog should be the least of their worries!
By the way, I like the idea of getting a new 2pea name to copy and paste their own bullshit back on their board. Yeah I said THEIR board because no attempt I've ever made to fit in has worked.
Losers.
fumd =find
sorry
Anonymous said...
You know what I fumd funnier than hell about this is...
The 2peas dumbasses who are always preaching to use the ignore button on people can't even figure out how to ignore what goes onhere. If they weren't so damn nosey and righteous all the time, they wouldn't even know what was being said here. Now the stupid bitches are arguing amongst themselves over who has been pissedon the most and who defended who. Hell, this blog should be the least of their worries!
By the way, I like the idea of getting a new 2pea name to copy and paste their own bullshit back on their board. Yeah I said THEIR board because no attempt I've ever made to fit in has worked.
Losers.
12:48 PM
you sound so friendly I can't imagine why on earth you didn't fit in. ~giggle~
you sound so friendly I can't imagine why on earth you didn't fit in. ~giggle~
***
Can we all say it???
PASSIVE AGRESSIVE
Why don't you just say well maybe it's cause your a bitch?? It is the freaking passive agressive attacks on 2peas that are the most annoying. In case you haven't noticed we (collective we) do not want to be a part of your little board. We prefer to sit over hear and gossip about y'all. Just like you guys do on email and IM. Only difference is that we are not "hiding" who and what we are talking about. So you can preach your shit about "cowards" and "not saying under your own name" blah blah blah. How having the name StaceyAngel** gives YOU more right to post than ME is astounding and justs shows YOUR (collective you) stupidity.
Sonya said...
you sound so friendly I can't imagine why on earth you didn't fit in. ~giggle~
***
Can we all say it???
PASSIVE AGRESSIVE
Why don't you just say well maybe it's cause your a bitch?? It is the freaking passive agressive attacks on 2peas that are the most annoying. In case you haven't noticed we (collective we) do not want to be a part of your little board. We prefer to sit over hear and gossip about y'all. Just like you guys do on email and IM. Only difference is that we are not "hiding" who and what we are talking about. So you can preach your shit about "cowards" and "not saying under your own name" blah blah blah. How having the name StaceyAngel** gives YOU more right to post than ME is astounding and justs shows YOUR (collective you) stupidity.
1:08 PM
"bitter, party of one" don't worry Sonya hon you soon will have plenty of company I'm sure. ~SNORT~
"bitter, party of one" don't worry Sonya hon you soon will have plenty of company I'm sure. ~SNORT~
****
Well that was insightful thanks. Is the snort to indicate that you are snorting? I can assure you that I could read the sarcasm just fine. No need to waste 7 key types by typing snort.
Go Lauren!
I wish she had a better example to defend then KD but she is doing a good job with it. Aimmer is coming off like a real bitch too.
You will soon learn who the nice peas are, the neutral peas, the mean peas, and the handslappers are.
%%%%%%%%%%%%%%%%%%%%%%%%
LOL someone give me a list to make it easier.
Handslappers
Molove
Seanna
NicePeas
damn can't remember their names!
Neutral
damn can't remember their names!
MeanPeas
Molove
Monique (hell yeah)
Michelley
CarnationGirl (new one)
StacyAngel
Yvonne (but I like her though for some reason)
and some peas that I like
Burning Feather
Lauren
Manda
Cherry Moon
Mapchic
PDR (girl is nice and she tries so damn hard on that board)
Crazy Peas
Zaima
Sass
Fleur
Artistic Chick (man that girl is whacked)
Troll Peas
8
Anabella
There is more but I am tired.
Oh good lord! That thread is 6 pages already! What the fuck are they arguing over? Is Keri a bitch? Is Aimmer a bitch? Why doesn't kimberlydobbs shut the fuck up already!
"Seanna is STILL the name of my ass-wipe dispenser.
Molove is the 2peas NSBR cop....a keystone cop with a Wal-Mart water pistol!
Thank you Keriwest for the moronic comments! It is obvious that your broomstick is jammed a bit too far up your wide ass."
LMAO
Crazy peas:
Annabella
Steffie
Sassafras
Manda
supermom_ttf
Boring peas:
Peaving Diva
Heartcat
Mapchic
Drama queens:
Scrapperwithaview
Supermom_ttf
Lulusmom
Chip on the shoulder pea:
Grinning Cat
Dumb peas:
Scrapbrooker
ScrappinRandy
LadyRen
scrappylicious
Annabella
Nope your list is WAY off:
Crazy peas:
Kimberlydobbs
Seanna
Steffie
Sassafras
Mapchic
Boring peas:
Peaving Diva
Drama queens:
Scrapperwithaview
Supermom_ttf
Lulusmom
Annabella
Mely
Dumb peas:
Paigepea
Mowse
Add kandkrose to the dumbpea list for this thread
http://www.twopeasinabucket.com/
mb.asp?cmd=display&thread_id=1771463
scrappylicious hardly ever posts to the board now, but she's sweet as pie and if you get her in a political discussion she's no dummy.
Your list has tons of flaws! You obviously don't know the peas well.
We need a category for peas who think they're funny but they're not. I nominate Seanna and Mary Mary.
I love Sock Monkey! I think she has the best sense of humor.
What I always find amusing is that the Peas who are all at war with each other are so much alike I can barely tell them apart.
MaryMary is so not funny.
She is the shame of the LDS on the board.
"We need a category for peas who think they're funny but they're not. I nominate Seanna and Mary Mary."
I second that!
I love how they can't even focus on killing the blog. LOL
UNITE 2peas
Is that a hard concept?
Lauren said...
People are free to 'feel' or believe whatever they wish. But, it's not right to post these things. And, if it's ok to do it to Kimberly, then it's ok to do it to Keri, to Mely, to Steph and to all of the other people the blogger and the commentators are doing it to.
****
Good point. Although KD is annoying as shit.
Keri is really taking this stuff personal.
Keri why don't you just think twice before sharing that you have 23 TVs? huge house? It isn't really that hard. If being a "braggart" is the worse that can be said about you???
That's not much to cry about.
"KD is annoying as shit."
Seriously! Blogger you should do an entry on her.
They seriously need a life over there. Don't you dare let those boring no life people stop your blog. They really need a hobby, maybe scrapbooking???
Dear Lauren,
This letter is a reminder that your 2Peas b!tch account has remained in an overdraft status (negative balance) for twenty (20) or more consecutive days as of today's date. Your account is currently overdrawn on the amount of :
10 unprovoked snarks
10 provoked snarks
1 stupid b!tch
1 regular b!tch
1 fat f*ck
Please ensure that your account remains in good standing by bringing it to a positive balance within ten (10) days of the date of this letter. Should you fail to do so, your "Bounce Protection" will be suspended.
If you are unaware of this situation or believe an error has occurred, we encourage you to contact our Customer Support Department at (666)TWO-PEASS, or visit any branch at 2Peas bank of B!tchiness.
We value your business and look forward to serving you for many years to come!
Sincerely,
2PEAS B!tch Patrol
- sylvia71
"They seriously need a life over there. Don't you dare let those boring no life people stop your blog. They really need a hobby, maybe scrapbooking???"
LMAO
Wow how could you forget Sammel for the dumb pea list?
kimberlydobbs continues to proof what a psycho she is on page 7 of the thread. Someone needs to remind her to take her medicine everyday, something is seriously off with her. And she's too dumb to see that everyone is shaking their head and laughing at her stupidity.
Why does Mary Mary think she's so funny? STUPID is more like it.
Oh, that Zaima - I feel SO SORRY for her kids! For heaven's sake, reading that ridiculous drama in her life is exhausting. It was awful to see her pick up and "fall in love" so quickly. And she wonders why the kids have behavior problems at school and with her friends??????!!!! Concentrate on getting yourself and your life together, but mostly concentrate on your children.
What I don't get about ZaAiMa is that she forced us to read long threads about her divorce problems, yet she doesn't tell us a peep about her new boyfriend. Probably doesn't want us to know how fast she got herself a new man. Does anyone actually know what her husband actually did to be sent to jail?
Did Zaima ever reveal what her ex did? She said she would once it was over.
To the person who keeps cutting and pasting...you are considerably rude. If you don't want to come over here, then don't, but to do this stupid crap is pretty much the most stupid thing you could do.
I feel like I'm in high school again, with all of the "popular" people picking on those of us who weren't as popular. Like they are better scrapbookers, moms, women, etc., than the rest of us is. Well, the only thing I can say is what comes around, goes around. Treat people like crap, you'll be treated like crap eventually. I hope half these women get what's coming to them in the lines of karma...
"2PEAS B!tch Patrol
- sylvia71 "
ROFLMAO!!
As for ZaMai (whatever the hell it is) I don't think she posts too much about the new bf because she was gently (since she's a popular pea) chastised about jumping into another relationship so quick before her divorce was even final. I think someone on here posted her ex stole military secrets.
Lyndajj2 said...
To the person who keeps cutting and pasting...you are considerably rude. If you don't want to come over here, then don't, but to do this stupid crap is pretty much the most stupid thing you could do.
I feel like I'm in high school again, with all of the "popular" people picking on those of us who weren't as popular. Like they are better scrapbookers, moms, women, etc., than the rest of us is. Well, the only thing I can say is what comes around, goes around. Treat people like crap, you'll be treated like crap eventually. I hope half these women get what's coming to them in the lines of karma...
6:35 PM
Lynda sweetie, Sonya has been holding the table for you all day and she's starving. Now get over there right now so she can have dinner.
Anonymous said...
Lyndajj2 said...
To the person who keeps cutting and pasting...you are considerably rude. If you don't want to come over here, then don't, but to do this stupid crap is pretty much the most stupid thing you could do.
I feel like I'm in high school again, with all of the "popular" people picking on those of us who weren't as popular. Like they are better scrapbookers, moms, women, etc., than the rest of us is. Well, the only thing I can say is what comes around, goes around. Treat people like crap, you'll be treated like crap eventually. I hope half these women get what's coming to them in the lines of karma...
6:35 PM
Lynda sweetie, Sonya has been holding the table for you all day and she's starving. Now get over there right now so she can have dinner.
6:39 PM
Stephanie has arrived. Please place your orders ladies.
Did Zaima ever reveal what her ex did? She said she would once it was over.
I don't think she ever did. My BS meter has been on overdrive with her since about her 3rd post about her family problems. It got Lifetime movie dramatic for a time.
"I think someone on here posted her ex stole military secrets."
ZaAiMa 's husband only did about 4 months in jail, he probably only stole office supplies.
Oh, man, not Heartcat! The opening ceremony would take HOURS and everyone would fall asleep.
Anonymous said...
Did Zaima ever reveal what her ex did? She said she would once it was over.
I don't think she ever did. My BS meter has been on overdrive with her since about her 3rd post about her family problems. It got Lifetime movie dramatic for a time.
Didn't she have to sell the minivan and move to Il to live with her parnets cause he had all the money. Her posts make ya feel even more sorry for her kids everytime the bullshit comes flowing out of her mouth.
"Anyone want to suggest a team leader? ;)"
Oh, man, not Heartcat! The opening ceremony would take HOURS and everyone would fall asleep.
Hmm, thanks on what Zaima's husband allegedly did. Four months for stealing military secrets? Nope.
I wonder what he really did. What a mess all the way around.
stephanie480 said...
I am posting this as the thread goes into its 7th page. I love how they all are BTT-ing the thread. Blogger, you deserve an Oscar for the most controversial blog!
There are enough retards on the above mentioned thread to form an ADULT Special Olympics team!
Anyone want to suggest a team leader? ;)
---------------------
Team leader - they'd all be bossing everyone around on what to do and what to say and how to say and do it, so nothing would get done.
"Didn't she have to sell the minivan and move to Il to live with her parnets cause he had all the money. Her posts make ya feel even more sorry for her kids everytime the bullshit comes flowing out of her mouth."
He didn't make much money to begin with and she didn't work even though she had a college degree. In Il she got a substitute teaching job, but said she didn't want to work, okay so how are you going to support yourself? Recently she posted about moving to another city for a better job, so you're leaving the free house you got?
Anonymous said...
Did Zaima ever reveal what her ex did? She said she would once it was over.
6:29 PM
Quite a few peas know what he did. It was actually posted about on peas but then someone deleted it.
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation
"There are enough retards on the above mentioned thread to form an ADULT Special Olympics team! "
It is so refreshing that we can use the word retard freely in everyday speech as it was intended.
"Quite a few peas know what he did. It was actually posted about on peas but then someone deleted it."
SPILL!!!
That article seems a little outdated.
I'm currently suffering from a vile case of da do run runs brought on by a weekend consisting of a few too many coronas. Got any advice for that?
I heard he had stolen some military equipment and sold it. Hey genius, if you're going to steal stolen government issue equipment, don't do it on ebay ROFL.
Ok I dont know that it was ebay but he was dumb enough to do it, and get caught, if that's what it was.
I See The SHIT TALKER Is Back
LOSER!
Anonymous said...
I heard he had stolen some military equipment and sold it. Hey genius, if you're going to steal stolen government issue equipment, don't do it on ebay ROFL.
Are you for real? ...LOL that is some funny shit... what a DUMBASS!
Finally the truth about ZaAiMa!
ZaAiMa-
Her husband got caught in the recent Navy Supply theft sting.
For a while the Navy was issueing government credit cards to commands to purchase supplies. The supply types all had them. They figured out away to buy stuff with the card, sell it on Ebay and put the funds back without getting caught. Well a whole bunch did get caught including her husband.
The were manily misappropriating items like Palm Pilots and selling them on Ebay. This scandal rocked the Navy about 2 years ago and they are still prosecuting cases as they are uncovered.
If you remember she was worried they would possibly go after her...he used her Ebay account. There is at least 1 Naval Officer doing hard time in Leavenworth, and many others who went to the brig. Basically they busted the Senior guys and they in turn turned in the junior guys to get less time.
Anonymous said...
ZaAiMa-
Her husband got caught in the recent Navy Supply theft sting.
For a while the Navy was issueing government credit cards to commands to purchase supplies. The supply types all had them. They figured out away to buy stuff with the card, sell it on Ebay and put the funds back without getting caught. Well a whole bunch did get caught including her husband.
The were manily misappropriating items like Palm Pilots and selling them on Ebay. This scandal rocked the Navy about 2 years ago and they are still prosecuting cases as they are uncovered.
If you remember she was worried they would possibly go after her...he used her Ebay account. There is at least 1 Naval Officer doing hard time in Leavenworth, and many others who went to the brig. Basically they busted the Senior guys and they in turn turned in the junior guys to get less time.
WOW! He's a real winner.. and to think he produced 2 kids... I feel sorry for those boys, Hopefully she will get them the help they need so they don't follow the same steps there daddy has.
"Hopefully she will get them the help they need so they don't follow the same steps there daddy has."
-------------
She can't - she's too busy dating and going out for the weekend trips and all, you know. Blech.
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation is critical for many reasons, but particularly because it allows the physician to define the type of constipation problem. This, in turn, directs the diagnosis and treatment. For example, if defecation is painful, the physician knows to look for anal problems such as a narrowed anal sphincter or an anal fissure. If small stools are the problem, there is likely to be a lack of fiber in the diet. If the patient is experiencing significant straining, then pelvic floor dysfunction is likely.
The history also uncovers medications and diseases that can cause constipation. In these cases, the medications can be changed and the diseases can be treated.
A careful dietary history-which may require keeping a food diary for a week or two-can reveal a diet that is low in fiber and may direct the physician to recommend a high-fiber diet. A food diary also allows the physician to evaluate how well a patient increases his dietary fiber during treatment.
Physical examination: A physical examination may identify diseases (e.g., scleroderma) that can cause constipation. A rectal examination with the finger may uncover a tight anal sphincter that may be making defecation difficult. If a stool-filled colon can be felt through the abdominal wall, it suggests that constipation is severe. Stool in the rectum suggests a problem with the anal, rectal, or pelvic floor muscles.
Blood tests: Blood tests may be appropriate in evaluating patients with constipation. More specifically, blood tests for thyroid hormone (to detect hypothyroidism) and for calcium (to uncover excess parathyroid hormone) may be helpful.
Abdominal x-ray: Large amounts of stool in the colon usually can be seen on simple x-ray films of the abdomen. The more stool that is seen, the more severe the constipation.
Barium enema: A barium enema (lower GI series) is an x-ray study in which liquid barium is inserted through the anus to fill the rectum and colon. The barium outlines the colon on the x-rays and defines the normal or abnormal anatomy of the colon and rectum. Tumors and narrowings (strictures) are among the abnormalities that can be detected with this test.
Colonic transit (marker) studies: Colonic transit studies are simple x-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on x-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an x-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon. In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles and/or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.
Defecography: Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.
Ano-rectal motility studies: Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.
Colonic motility studies: Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or all of the colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation.
What treatments are available for constipation?
There are many treatments for constipation, and the best approach relies on a clear understanding of the underlying cause.
Dietary fiber (bulk-forming laxatives): The best way of adding fiber to the diet is increasing the quantity of fruits and vegetables that are eaten. This means a minimum of five servings of fruits or vegetables every day. For many people, however, the amount of fruits and vegetables that are necessary may be inconveniently large or may not provide adequate relief from constipation. In this case, fiber supplements can be useful.
Fiber is defined as material made by plants that is not digested by the human gastrointestinal tract. Fiber is one of the mainstays in the treatment of constipation. Many types of fiber within the intestine bind to water and keep the water within the intestine. The fiber adds bulk (volume) to the stool and the water softens the stool.
There are different sources of fiber and the type of fiber varies from source to source. Types of fiber can be categorized in several ways, for example, by their source. The most common sources of fiber include fruits and vegetables, wheat or oat bran, psyllium seed (e.g., Metamucil, Konsyl), synthetic methyl cellulose (e.g., Citrucel), and polycarbophil (e.g., Equilactin, Konsyl Fiber). Polycarbophil often is combined with calcium (e.g., Fibercon). However, in some studies, the calcium-containing polycarbophil was not as effective as the polycarbophil without calcium. A lesser known source of fiber is an extract of malt (e.g., Maltsupex); however, this extract may soften stools in ways other than increasing fiber.
Increased gas (flatulence) is a common side effect of high-fiber diets. The gas occurs because the bacteria normally present within the colon are capable of digesting fiber to a small extent. The bacteria produce gas as a byproduct of their digestion of fiber. All fibers, no matter what their source, can cause flatulence. However, since bacteria vary in their ability to digest the various types of fiber, the different sources of fiber may produce different amounts of gas. To complicate the situation, the ability of bacteria to digest one type of fiber can vary from individual to individual. This variability makes the selection of the best type of fiber for each person (i.e., a fiber that improves the quality of the stool without causing flatulence) more difficult. Thus, finding the proper fiber for an individual becomes a matter of trial and error.
The different sources of fiber should be tried one by one. The fiber should be started at a low dose and increased every 1 to 2 weeks until either the desired effect on the stool is achieved or troublesome flatulence interferes. (Fiber does not work overnight.) If flatulence occurs, the dose of fiber can be reduced for a few weeks and the higher dose can then be tried again. (It generally is said that the amount of gas that is produced by fiber decreases when the fiber is ingested for a prolonged period of time; however, this has never been studied.) If flatulence remains a problem and prevents the dose of fiber from being raised to a level that affects the stool satisfactorily, it is time to move on to a different source of fiber.
When increasing amounts of fiber are used, it is recommended that greater amounts of water be consumed (e.g., a full glass with each dose). Presumably, the water prevents "hardening" of the fiber and blockage (obstruction) of the intestine. This seems like simple and reasonable advice. However, ingesting larger amounts of water has never been shown to have any beneficial effect on constipation, with or without the addition of fiber. (There is already a lot of water in the intestine and extra water is absorbed and excreted in the urine.) It is reasonable to drink enough fluids to prevent dehydration because with dehydration there may be reduced intestinal water.
Because of concern about obstruction, persons with narrowings (strictures) or adhesions (scar tissue from previous surgery) of their intestines should not use fiber unless it has been discussed with their physician. Some fiber laxatives contain sugar, and diabetic patients may need to select sugar-free products.
Lubricant laxatives: Lubricant laxatives contain mineral oil as either the plain oil or an emulsion (combination with water) of the oil. The oil stays within the intestine, coats the particles of stool, and presumably prevents the removal of water from the stool. This retention of water in the stool results in softer stool. Mineral oil generally is used only for the short-term treatment of constipation since its long-term use has several potential disadvantages. The oil can absorb fat-soluble vitamins from the intestine and, if used for prolonged periods, may lead to deficiencies of these vitamins . This is of particular concern in pregnancy during which an adequate supply of vitamins is important for the fetus. In the very young or very elderly in whom the swallowing mechanism is not strong or is impaired by strokes, small amounts of the swallowed oil may enter the lungs and cause a type of pneumonia called lipid pneumonia. Mineral oil also may decrease the absorption of some drugs such as warfarin and oral contraceptives, thereby decreasing their effectiveness. Despite these potential disadvantages, mineral oil can be effective when short-term treatment is necessary.
Emollient laxatives (stool softeners): Emollient laxatives are generally known as stool softeners. They contain a compound called docusate (e.g., Colace). Docusate is a wetting agent that improves the ability of water within the colon to penetrate and mix with stool. This increased water in the stool softens the stool. Studies, however, have not shown docusate to be consistently effective in relieving constipation. Nevertheless, stool softeners often are used in the long-term treatment of constipation. It may take a week or more for docusate to be effective. The dose should be increased after one to two weeks if no effect is seen. Although docusate generally is safe, it may allow the absorption of mineral oil and some medications from the intestine. Absorbed mineral oil collects in tissues of the body, for example, the lymph nodes and the liver, where it causes inflammation. It is not clear if this inflammation has any important consequences, but it generally is felt that prolonged absorption of mineral oil should not be allowed. The use of emollient laxatives is not recommended together with mineral oil or with certain prescription medications. Emollient laxatives are commonly used when there is a need to soften the stool temporarily and make defecation easier (e.g., after surgery, childbirth, or heart attacks). They are also used for individuals with hemorrhoids or anal fissures.
Hyperosmolar laxatives: Hyperosmolar laxatives are undigestible, unabsorbable compounds that remain within the colon and retain the water that already is in the colon. The result is softening of the stool. The most common hyperosmolar laxatives are lactulose (e.g., Kristalose), sorbitol, and polyethylene glycol (e.g., MiraLax). They are available by prescription only. These laxatives are safe for long-term use and are associated with few side effects. Hyperosmolar laxatives may be digested by colonic bacteria and turned into gas, which may result in unwanted abdominal bloating and flatulence. This effect is dose-related. Therefore, gas can be reduced by reducing the dose of the laxative. In some cases, the gas will decrease over time.
Saline laxatives: Saline laxatives contain non-absorbable ions such as magnesium, sulfate, phosphate, and citrate (e.g., magnesium citrate, magnesium hydroxide, sodium phosphate). These ions remain in the colon and cause water to be drawn into the colon. Again, the effect is softening of the stool. Magnesium also may have mild stimulatory effects on the colonic muscles. Saline laxatives act within a few hours. In general, potent saline laxatives should not be used on a regular basis. The magnesium in magnesium-containing laxatives is partially absorbed from the intestine and into the body. Magnesium is eliminated from the body by the kidneys. Therefore, individuals with impaired kidney function may develop toxic levels of magnesium from chronic (long duration) use of magnesium-containing laxatives. If major diarrhea develops with the use of saline laxatives and the lost fluid is not replaced by the consumption of liquids, dehydration may result. For constipation, the most frequently-used and mildest of the saline laxatives is milk of magnesia. Epsom Salt is a more potent saline laxative that contains magnesium sulfate.
Stimulant laxatives: Stimulant laxatives cause the muscles of the small intestine and colon to propel their contents more rapidly. They also increase the amount of water in the stool, either by reducing the absorption of the water in the colon or by causing active secretion of water in the small intestine. The most commonly-used stimulant laxatives contain cascara (castor oil), senna (e.g., Ex-Lax, Senokot), and aloe. Stimulant laxatives are very effective, but they can cause severe diarrhea with resulting dehydration and loss of electrolytes (especially potassium). They also are more likely than other types of laxatives to cause intestinal cramping. There is concern that chronic use of stimulant laxatives may damage the colon and worsen constipation, as previously discussed. Bisacodyl (e.g., Dulcolax, Correctol) is a stimulant laxative that affects the nerves of the colon which, in turn, stimulate the muscles of the colon to propel its contents. Prunes also contain a mild colonic stimulant.
Enemas: There are many different types of enemas. By distending the rectum, all enemas (even the simplest type, the tap water enema) stimulate the colon to contract and eliminate stool. Other types of enemas have additional mechanisms of action. For example, saline enemas cause water to be drawn into the colon. Phosphate enemas (e.g., Fleet phosphosoda) stimulate the muscles of the colon. Mineral oil enemas lubricate and soften hard stool. Emollient enemas (e.g., Colace Microenema) contain agents that soften the stool.
Enemas are particularly useful when there is impaction, which is hardening of stool in the rectum. In order to be effective, the instructions that come with the enema must be followed. This requires full application of the enema, appropriate positioning after the enema is instilled, and retention of the enema until cramps are felt. Defecation usually occurs between a few minutes and one hour after the enema is inserted.
Enemas are meant for occasional rather than regular use. The frequent use of enemas can cause disturbances of the fluids and electrolytes in the body. This is especially true of tap water enemas. Soapsuds enemas are not recommended because they can seriously damage the rectum.
Suppositories: As is the case with enemas, different types of suppositories have different mechanisms of action. There are stimulant suppositories containing bisacodyl (e.g., Dulcolax). Glycerin suppositories are believed to have their effect by irritating the rectum. The insertion of the finger into the rectum when the suppository is placed may itself stimulate a bowel movement.
Combination products: There are many products that combine different laxatives. For example, there are oral products that combine senna and psyllium (Perdiem), senna and docusate (Senokot-S), and senna and glycerin (Fletcher's Castoria). One product even combines three laxatives, senna-like casanthranol, docusate, and glycerin (Sof-lax Overnight). These products may be convenient and effective, but they also contain stimulant laxatives. Therefore, there is concern about permanent colonic damage with the use of these products and they should not be used for long term treatment.
Miscellaneous drugs: Several prescribed drugs that are used to treat medical diseases consistently cause (as a side effect) loose stools, even diarrhea. There actually are several small studies that have examined these drugs for the treatment of constipation.
Colchicine is a drug that has been used for decades to treat gout. Most patients who take colchicine note a loosening of their stools. Colchicine has also been demonstrated to relieve constipation effectively in patients without gout.
Misoprostil (Cytotec) is a drug used primarily for preventing stomach ulcers caused by non-steroidal anti-inflammatory drugs such as ibuprofen. Diarrhea is one of its consistent side-effects. Several studies have shown that misoprostil is effective in the short term treatment of constipation. Misoprostil is expensive, and it is not clear if it will remain effective and safe with long term use. Therefore, its role in the treatment of constipation remains to be determined.
Orlistat (Xenical) is a drug that is used primarily for reducing weight. It works by blocking the enzymes within the intestine that digest fat. The undigested fat is not absorbed, which accounts for the weight loss. Undigested fat is digested by bacteria within the intestine and the products of this bacterial digestion promote the secretion of water. The products of digestion also may affect the intestine in other ways, for example, by stimulating the intestinal muscles. In fact, in studies, orlistat has been shown to be effective in treating constipation. Orlistat has few significant side effects, which is consistent with the fact that only very small amounts of the drug are absorbed from the intestine.
It is unclear if these prescribed drugs should be used for the treatment of constipation. Although it is difficult to recommend them specifically just for the treatment of constipation, they might be considered for constipated individuals who are overweight, have gout, or need protection from non-steroidal anti-inflammatory drugs.
Exercise: People who lead sedentary lives are more frequently constipated than people who are active. Nevertheless, limited studies of exercise on bowel habit have shown that exercise has minimal or no effect on the frequency of bowel movements. Thus, exercise can be recommended for its many other health benefits, but not for its effect on constipation.
Biofeedback: Most of the muscles of the pelvis surrounding the anus and rectum are under some degree of voluntary control. Thus, biofeedback training can teach patients with pelvic floor dysfunction how to make their muscles work more normally and improve their ability to defecate. During ano-rectal biofeedback training, a pressure-sensing catheter is placed through the anus and into the rectum. Each time a patient contracts the muscles, the muscles generate a pressure that is sensed by the catheter and recorded on a screen. By watching the pressures on the screen and attempting to modify them, patients learn how to relax and contract the muscles more normally.
Surgery: For individuals with problematic constipation that is due to diseases of the colon or laxative abuse, surgery is the ultimate treatment. During surgery, most of the colon, except for the rectum (or the rectum and part of the sigmoid colon), is removed. The cut end of the small intestine is attached to the remaining rectum or sigmoid colon. In patients with colonic inertia, surgery is reserved for those who do not respond to all other therapies. If the surgery is to be done, there must be no disease of the small intestinal muscles. Normal small intestinal muscles are evidenced by normal motility studies of the small intestine itself.
Electrical pacing: Electrical pacing is still in its experimental phases. Electrical pacing may be done using electrodes implanted into the muscular wall of the colon. The electrodes exit the colon and are attached to an electrical stimulator. Alternatively, stimulation of the sacral skin can be used to stimulate nerves going to the colon. These techniques are promising, but much more work lies ahead before their role in treating constipation, if any, has been defined.
What is the approach to the evaluation and treatment of constipation?
There are several principles in approaching the evaluation and treatment of constipation. The first principle is to differentiate between acute (recent onset) and chronic (long duration) constipation. Thus, with acute constipation or constipation that is worsening, it is necessary to assess for the cause early so as not to overlook a serious illness that should be treated urgently. The second principle is to start treatment early and use the treatments that have the least potential for harm. This will prevent constipation from worsening, and it also will prevent potential damage to the colon that can be caused by the frequent use of stimulant laxatives. The third principle is to know when it is time to evaluate the cause of chronic constipation. Evaluation for the cause of chronic constipation needs to be done if there is no response to the simple treatments.
The goal of treatment in constipation should not be a bowel movement every day, but a bowel movement every 2 to 3 days without difficulty (without straining). Start with the simple things. Don't suppress urges to defecate. When the urge comes, find a toilet. With the assistance of your physician and pharmacist, determine if there are drugs that you are taking that could be contributing to the constipation. See if the drugs can be discontinued or changed. Increase the fiber in your diet by consuming more fruits, vegetables, and whole grains. (There are other health benefits from this recommendation as well.) It may be difficult to get enough fiber in the diet to effectively treat constipation, so don't hesitate to take fiber supplements if necessary (wheat bran, psyllium, etc.). Use increasing amounts of fiber and/or change the type of fiber consumed until there is a satisfactory result. Don't expect fiber to work overnight. Allow weeks for adequate trials.
What if constipation does not respond to these simple, safe measures? These efforts should not be discontinued but other measures should be added. If the constipation is infrequent, that is, every few weeks (as it can be when due to the menstrual cycle), it probably doesn't matter what other measures are added-emollient, saline, or hyper-osmolar laxatives, enemas, and suppositories. Even stimulant laxatives every 4 to 6 weeks are unlikely to damage the colon. Unfortunately, the tendency when using stimulant laxatives is to unconsciously increase the frequency of their use. Before you know it, you're taking them every week, or more often, and permanent damage might result.
If constipation is a continuous rather than an intermittent problem, probably the safest laxatives to take on a regular basis are the hyper-osmolar laxatives. They require a prescription and, therefore, necessitate a call to a physician. As with fiber, increasing doses of different hyper-osmolar laxatives should be tried over several weeks until a satisfactory type and dose of laxative is found. Hyper-osmolar laxatives, however, can be expensive. Milk of magnesia is the mildest of the saline laxatives, is inexpensive, and provides a good alternative. Most patients can adjust the dose of milk of magnesia to soften the stool adequately without developing diarrhea or leakage of stool.
Prunes and prune juice have been used for many years to treat mild constipation. There is no evidence that the mild stimulant effects of prunes or prune juice damage the colon. Stronger stimulant laxatives usually are recommended only as a last resort after non-stimulant treatments have failed. Many people take herbs to treat their constipation because they feel more comfortable using a "natural" product. Unfortunately, most of these herbal preparations contain stimulant laxatives and their long term use raises the possibility that they also may damage the colon.
When should chronic constipation be evaluated?
If the main problem is straining to push the stool out, chronic constipation should probably be evaluated early. This difficulty might be due to pelvic floor dysfunction, and the treatment of choice is biofeedback training, not laxatives. If the constipation is not responding to the simple measures discussed previously with the addition of hyper-osmolar laxatives or milk of magnesia, it is time to consult a physician for an evaluation. If your primary doctor is not comfortable performing the evaluation or you do not have confidence in his evaluation, ask for a referral to a gastroenterologist. Gastroenterologists deal with constipation frequently and are very familiar with the evaluation techniques discussed previously.
What's new in the treatment of constipation?
Each part of the intestine (stomach, small intestine, and colon) has a network of nerves that controls its muscles. A great deal of research is being done in order to gain an understanding of how these nerves control each other and ultimately the muscles. Much of this research involves the study of neurotransmitters. (Neurotransmitters are chemicals that nerves use to communicate with each other.) This research is allowing scientists to develop drugs that stimulate (and inhibit) the various nerves of the colon which, in turn, cause the muscles of the colon to contract and propel the colonic contents. Such drugs have great potential for the treatment of constipation that is due to colonic inertia. The first of these drugs is in clinical trials and is likely to be available soon. These drugs are an exciting development because they offer a new treatment for a difficult-to-treat form of constipation. Nevertheless, there are many questions about these types of drugs that must be answered. How effective are they? Will they work in many or only a few patients? Will they work in patients who have damaged their nerves with stimulant laxatives? Since these medications are likely to be used for a lifetime, how safe will they be with many years of use? Will they be used indiscriminately in situations for which simple treatments (e.g., fiber) or more appropriate treatments (e.g., biofeedback training) should be used?
Constipation At A Glance
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
Constipation usually is caused by the slow movement of stool through the colon.
There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal x-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
The goal of therapy for constipation is one bowel movement every 2 to 3 days without straining.
Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.
Last Editorial Review: 1/11/2005
Constipation
Medical Author: Jay W. Marks, M.D.
Medical Editor: Leslie J. Schoenfield, M.D., Ph.D.
What is constipation?
What causes constipation?
How is constipation evaluated?
What treatments are available for constipation?
What is the approach to the evaluation and treatment of constipation?
When should chronic constipation be evaluated?
What's new in the treatment of constipation?
Constipation At A Glance
What is constipation?
Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation. Constipation can also alternate with diarrhea. This pattern is more commonly considered as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (e.g., tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary weight loss. In contrast, the evaluation of chronic constipation may not require immediate attention, particularly if simple measures bring relief.
What causes constipation?
Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.
Medications: A frequently over-looked cause of constipation is medications. The most common offending medications include:
Narcotic pain medications such as codeine (e.g., Tylenol #3), oxycodone (e.g., Percocet), and hydromorphone (Dilaudid);
Antidepressants such as amitriptylene (Elavil) and imipramine (Tofranil)
Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
Iron supplements
Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
Aluminum-containing antacids such as Amphojel and Basaljel
In addition to the medications listed above, there are many others that can cause constipation. Simple measures (e.g., increasing dietary fiber) for treating the constipation caused by medications often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a non-steroidal anti-inflammatory drug (e.g., ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications (e.g., fluoxetine or Prozac) may be substituted for amitriptylene and imipramine.
Habit: Bowel movements are under voluntary control. This means that the normal urge people feel when they need to have a bowel movement can be suppressed. Although occasionally it is appropriate to suppress an urge to defecate (e.g., when a bathroom is not available), doing this too frequently can lead to a disappearance of urges and result in constipation.
Diet: Fiber is important in maintaining a soft, bulky stool. Diets that are low in fiber can, therefore, cause constipation. The best natural sources of fiber are fruits, vegetables, and whole grains.
Laxatives: One suspected cause of severe constipation is the over-use of stimulant laxatives (e.g., senna, castor oil, and certain herbs). An association has been shown between the chronic use of stimulanat laxatives and damage to the nerves and muscles of the colon, and it is believed that the damage is responsible for the constipation. It is not clear, however, whether the laxatives have caused the damage or whether the damage existed prior to the use of laxatives and, indeed, has caused the laxatives to be used. Nevertheless, because of the possibility that stimulant laxatives can damage the colon, most experts recommend that stimulant laxatives be used as a last resort after non-stimulant treatments have failed.
Hormonal disorders: Hormones can affect bowel movements. For example, too little thyroid hormone (hypothyroidism) and too much parathyroid hormone (by raising the calcium levels in the blood) can cause constipation. At the time of a woman's menstrual periods, estrogen and progesterone levels are high and may cause constipation. However, this is rarely a prolonged problem. High levels of estrogen and progesterone during pregnancy also can cause constipation.
Diseases that affect the colon: There are many diseases that can affect the function of the muscles and/or nerves of the colon. These include diabetes, scleroderma, intestinal pseudo-obstruction, Hirschsprung's disease, and Chagas disease. Cancer or narrowing (stricture) of the colon that blocks the colon likewise can cause a decrease in the flow of stool.
Central nervous system diseases: A few diseases of the brain and spinal cord may cause constipation, including Parkinson's disease, multiple sclerosis, and spinal cord injuries.
Colonic inertia: Colonic inertia is a condition in which the nerves and/or muscles of the colon do not work normally. As a result, the contents of the colon are not propelled through the colon normally. The cause of colonic inertia is unclear. In some cases, the muscles or nerves of the colon are diseased. Colonic inertia can also be the result of the chronic use of stimulant laxatives. In most cases, however, there is no clear cause.
Pelvic floor dysfunction: Pelvic floor dysfunction (also known as outlet obstruction or outlet delay) refers to a condition in which the muscles of the lower pelvis that surround the rectum (the pelvic floor muscles) do not work normally. These muscles are critical for defecation (bowel movement). It is not known why these muscles fail to work properly in some people, but they can make the passage of stools difficult even when everything else is normal.
How is constipation evaluated?
A careful history and physical examination is important in all patients with constipation. There are many tests that can be used to evaluate constipation. Most patients need only a few basic tests. The other tests are reserved for individuals who have severe constipation or whose constipation does not respond easily to treatment.
History: A careful medical history from a patient with constipation
"Hopefully she will get them the help they need so they don't follow the same steps there daddy has."
She's keeping the oldest one drugged up.
The spammer is going to all that trouble to copy and paste when all we have to do is click their name and their whole post disappears.
Anonymous said...
The spammer is going to all that trouble to copy and paste when all we have to do is click their name and their whole post disappears.
I know how easy is it to get rid of that shit..... What a LOSER.. and to think she comes here just to post and run.... what a fuckin waste of time.. for her.... BWAHAHAHAHAHAHAHA
Anonymous said...
"Hopefully she will get them the help they need so they don't follow the same steps there daddy has."
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She can't - she's too busy dating and going out for the weekend trips and all, you know. Blech.
8:02 PM
8:09 PM
Anonymous said...
"Hopefully she will get them the help they need so they don't follow the same steps there daddy has."
She's keeping the oldest one drugged up
She just needs to give them to someone else who can raise them properly. Both of those kids are on a sad path to nowhere
As for the list; I'd add Mary Mary to the handslapper list, Sammel to the crazy pea list, Wade's girl to the nice list.
Lauren must have her meds regulated correctly. She seems to be making sense and not flipping out on the 7 page blog thread.
I just think ZaAiMa is lucky to find a man at her size.
'Lauren must have her meds regulated correctly. She seems to be making sense and not flipping out on the 7 page blog thread.'
It's not that her meds are regulated... it's that she's not drunk!!!!!
Lauren giving advice on how to treat others on Two Peas is priceless! :) Someone should copy that shit to post during her next meltdown.
Constipation girl, I have to hand it to you coming up with such a brilliant plan to stop the blog. It's pure genius. All that copy and pasting and all we have to do is collapse the comment that takes less than a second.
You're going to run everyone off because they'll get tired of having to click a few times during a thread! You're so clever like a drooling retard on a little school bus. Is your name on the dumb peas list?
" If they weren't so damn nosey and righteous all the time, they wouldn't even know what was being said here."
So that makes it ok to come over here and slam people to pieces?
I don't think anyone deserves the treatment they have been getting here. Somehow the nastiest cruelest peas have managed to escape this blog.
-I don't think anyone deserves the treatment they have been getting here. Somehow the nastiest cruelest peas have managed to escape this blog. -
If you're that emotionally involved perhaps you should consider how much time you spend in the virtual world.
You have to wonder about people who have supposedly great families, money, and a nice home yet spend so much time online. They have disconnected from the real world for an online one. It's sad to see so many women doing it. If they were happy with their own lives, they would be living theirs instead of escaping into their computers.
If you're worried about what anonymous X user is saying about you that should be a wake up call that you're spending too much energy on what amounts to nothing in the grand scheme of your life.
I don’t think any of the regular peas could shut off their personal home computer for an entire month or even a week. I don’t think they could emotionally handle it. It gives them a fix like a drug to a junkie or a junk food to an overeater. The fantasy online world has turned into a seemly real world for them to devote so much energy to it.
Very well said, Jess. I cringe when I see the volume of posts from some of them - how long they're online during the day AND night! I can't imagine how they interact with their kids with all that computer time.
I don't read all the posts, especially the longer ones - I'll breeze through some of them here and there. Even that takes time, so I can't imagine the amount of time they do spend.
Like SailorLady when she has her kids for the weekend - I looked at her posts one day when she was complaining of sending her kids back to the father, and she had posts practically every hour all day - so sad. Yet she's such an arbiter of all that is right and wrong.
And I don't subscribe to the notion that the most obnoxious and self-important peas were the popular girls in high school. I've seen that said several times.
I believe just the opposite: That they were invisible in school. I'll bet they were the bossy bully you couldn't stand to see coming. They've found an outlet for their behavior and misguided big egos there. No wonder they spend so much time creating their faux online life.
Somehow the nastiest cruelest peas have managed to escape this blog. -
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All the big dogs have been discussed here except Mapchic. Which once again leads me to believe that Ashley Nicole is the author of this blog.
I'm sure it's just not as fun for those most obnoxious women who have moved to another board to not have the "audience" of a large board like 2Peas. It's like a breath of fresh air that they left and like someone farted in the room when they reappear.
http://www.twopeasinabucket.com/
mb.asp?cmd=display&thread_id=1773075
ZaAiMa is a moron. She dumped a good man for no good reason. She obviously prefers disfunctional relationships.
Before the spelling police come around disfunctional should have been dysfunctional.
What makes me laugh incredibly hard is the fact that a lot of those bitches on that thread (and believe me I did not read anywhere past the first page) are basically saying that they don't come over here and post.
You know they do. They know they do. So let them live their little pathetic lie of a life and try continuously to be something or someone they are not.
They try so hard to play innocent and they are failing miserably. Just a bunch of no-life liars. Of course, gotta hand it to Mother Molove, her comment (and it was the very first one, I will add) started some shit over there.
But I thought she was the 'gracefull, class-act, even-tempered shit don't stink' pea....hmm makes me wonder how much her shit just MIGHT stink.
I can't fucking stand her.
Pat
"People know me here, I'm pretty sure they understand I'm not a vile or controversial person just trying to stir stuff up" Quoted off the MB by Molove.
Yes, Mo we know you and can't stand you.
Seanna, Monique, Molove, those are the three meanest people on the MB Lauren pales to the venom those three spew out. All under the guise of "it can't be healthy for you to be here you should leave"
They are Cunts, smelly, nasty, unwashed, used up, and loose lipped.
"People know me here, I'm pretty sure they understand I'm not a vile or controversial person just trying to stir stuff up" Quoted off the MB by Molove.
Yes, Mo we know you and can't stand you.
Seanna, Monique, Molove, those are the three meanest people on the MB Lauren pales to the venom those three spew out. All under the guise of "it can't be healthy for you to be here you should leave"
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True about Molove. But Lauren is crueler than any of them.
""People know me here, I'm pretty sure they understand I'm not a vile or controversial person just trying to stir stuff up" Quoted off the MB by Molove."
**snort**
I hadn't seen that. She's pretty self-important and working the audience with confidene, huh?
Like SailorLady when she has her kids for the weekend - I looked at her posts one day when she was complaining of sending her kids back to the father, and she had posts practically every hour all day - so sad. Yet she's such an arbiter of all that is right and wrong.
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Really, wow just wow!
To the person who taught me how to collapse the cut and paste threads... I thank you! I hope you have a completely wonderful day, full of great times!!! You deserve it for teaching me that!
Lynda said...
To the person who taught me how to collapse the cut and paste threads... I thank you! I hope you have a completely wonderful day, full of great times!!! You deserve it for teaching me that!
9:15 AM
LMFAO
You couldn't figure that out yourself stupid. Lynda gets the idiot of the day award.
LMFAO
You couldn't figure that out yourself stupid. Lynda gets the idiot of the day award.
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I didn't know how to do that either. The people who still can't post links here deserve that award.
Anonymous said...
Let one of them honestly disagree with Seanna, Monique, Molove, or one like them and see how fast the pile-on starts.
You forgot to mention Yvonne, Ruth and Kelli. The ironic thing is that I find these women to be some of the nastiest women on the board. They seem to get a real kick out of being mean and nasty to anyone who dares to disagree with anything they have to say.
"You couldn't figure that out yourself stupid. Lynda gets the idiot of the day award."
And you get the crass and uncouth award.
And although I generally find the spelling/grammar police annoying, "stupid" in your OP is what is known as a direct address and should be set off with commas. Just trying to help you not look stupid, stupid.
You forgot to mention Yvonne, Ruth and Kelli. The ironic thing is that I find these women to be some of the nastiest women on the board. They seem to get a real kick out of being mean and nasty to anyone who dares to disagree with anything they have to say.
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You're right. I find it interesting how Kelli always pops up late at night to post back to back posts to one thread. Seanna must be emailing her for backup.
Yvonne is a straight up rude bitch who thinks she can get away with anything.
Ruth is "nice" but her handslapping puts her in the bitch category.
Very well said, Jess. I cringe when I see the volume of posts from some of them - how long they're online during the day AND night! I can't imagine how they interact with their kids with all that computer time.
*********************************
I am not a big poster at 2Ps, but talk about getting too wrapped up in a board! If you and Jess have so much time that you are actually RESEARCHING how much time people spend on the board then you are truly pathetic. Who the hell has the time to pay attention to anyone else but their own posts and their lives? Losers, I guess.
Some people get on while their kids are napping, some are at school. Some only come on at night, some just check in here and there during the day. It doesn't take long to scroll through, pick a couple of things that interest you and read or respond.
How do you know how long they are on the board unless you are actually taking the time to CHECK THEIR POSTS? Talk about obsessed. Pretty pathetic. Maybe you need to pay attention to your own lives and quit obsessing over who posts when. Amazing.
"If you and Jess have so much time that you are actually RESEARCHING how much time people spend on the board then you are truly pathetic. "
One doesn't have to do in depth research. Take Darlin Nikki for example, I took this from a comment on another blog entry:
10005 posts since 11/7/2005
1744 posts between 10/10/2005 and 11/7/2005
I don't need to look up her post frequency to know that is WAY more posts than the average user.
Some of us are at work with a light workload where we are parked in front of a computer for 8 hours. A SAHM I'm sure has things to do with her day, that she may chose to neglect for the board.
Some of us are at work with a light workload where we are parked in front of a computer for 8 hours. A SAHM I'm sure has things to do with her day, that she may chose to neglect for the board.
1:12 PM
____________
And that is an assumption you are making? I don't know anything about Nikki's life, I don't have time. I am an SAHM, my kids are at school (and I guess her one child is too), and like I said, I come on MAYBE, total, an hour a day. I have no idea how many times people post, when they post, etc. I don't care. I have my own life going on.
If the people complaining about others being on the board "so much", then they also must be on it all the time in order to even notice. OR they are researching people's posts. Which means they are the ones that need to step away from the keyboard and get a hobby. If you are so obsessed about the "popular peas" and what they are posting, when they are posting, or even using one minute to wonder if their families are being neglected, then you are WAY too wrapped up in the board.
My hour is up here, I am off to obssess about my life, not the lives of others I don't even know. Maybe the people who are so worried about others on the board need to do the same.
My hour is up here, I am off to obssess about my life, not the lives of others I don't even know. Maybe the people who are so worried about others on the board need to do the same.
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And yet you had time to obsess over people posting to this blog, writing a long ass comment, sounds like you're not taking your own advice.
Darlin Nikki
10005 posts since 11/7/2005
1744 posts between 10/10/2005 and 11/7/2005
----------------
Wow, just wow! Does she have a life?
I also find it very interesting that Mapchic is not mentioned by the blogger at all. She's in the top 5 crazy ass and most annoying Peas lists.
And yet you had time to obsess over people posting to this blog, writing a long ass comment, sounds like you're not taking your own advice.
2:38 PM
****************
TeeHee, did her comments sting a little bit? Must have. I could have typed and posted that in about minute. Yea, lots of time wasted there!
"TeeHee, did her comments sting a little bit? Must have. I could have typed and posted that in about minute. Yea, lots of time wasted there!"
TeeHee???!!! And, no, you guys complaining about the blog don't sting.
I don't think this blog is that much different from the Week in Review that MSP posted each week on 2Peas. A lot of what was posted was done for no other reason than to make fun of the OP's. No one seemed to have a problem with that. In fact, everyone thought it was funny.
You're absolutely right about MSP. People thought she was funny when she was really being bitchy and snarky.
Did anybody else think it was wierd when minzy said that her dh was practicing writing "Jaxon" over and over? Sounds more like a 4th grade girl with a crush. Maybe he made the 'o' into a flower?
I don't think this blog is that much different from the Week in Review that MSP posted each week on 2Peas. A lot of what was posted was done for no other reason than to make fun of the OP's. No one seemed to have a problem with that. In fact, everyone thought it was funny.
****
I forgot about that. You are so right. Everyone thought THAT was a hoot.
I see Yvonne had to give her 2 cents on that thread. Of course she is using her tired old phrase of "Ya Basta" because someone isn't agreeing with her. I'm surprised she hasn't asked everyone to sing Kumbaya. Get some new material already!
I see Yvonne had to give her 2 cents on that thread. Of course she is using her tired old phrase of "Ya Basta" because someone isn't agreeing with her. I'm surprised she hasn't asked everyone to sing Kumbaya. Get some new material already!
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PIMP
Slutty Evil Pea:
Ralonda
3 kids, 3 different dads
The Peas would roll over and die if they knew the true story about this phony ho.
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