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Irritable Bowel Syndrome (IBS) Health Center

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Irritable Bowel Syndrome (IBS), Constipation, and Laxatives

Many people with irritable bowel syndrome (IBS) turn to laxatives to relieve constipation, but laxatives usually offer limited help.

Although laxatives do ease constipation, there's no proof that they relieve stomach aches, bloating, and discomfort that come with IBS. That's because the drugs have never been thoroughly studied for the treatment of IBS in randomized controlled trials. In these trials, people are randomly assigned to different treatments without knowing which one they receive. Researchers then compare the effectiveness of different drugs or therapies. These types of studies are the only way to really know if a drug is effective.

This does not mean laxatives are out of the picture for IBS sufferers with constipation. Some doctors recommend them to increase the number of bowel movements.

"Laxatives have been shown to work for constipation. The difference comes in trying to do something with the abdominal pain and discomfort as well," says Philip Schoenfeld, MD, MSEd, MSc. He is the co-author of the IBS treatment guidelines published by the American College of Gastroenterology.

IBS, after all, is a disorder that involves trouble with bowel movements and stomachaches, distress, and bloating.

If you're considering laxatives for IBS-related constipation, make sure to talk with your doctor first. There are different kinds of laxatives. Some of them are safer than others for long-term treatment of constipation.

Osmotic Laxatives for IBS With Constipation

Osmotic laxatives pull water back into the colon, which softens stool so it is easier to pass for those with IBS and constipation. These laxatives are fairly safe to take for chronic constipation, says Beth Schorr-Lesnick, MD, FACG, a gastroenterologist at Montefiore Medical Center in Bronx, N.Y.

But they do have different effects on different people. They ease stool passage in most people, but in some they may also cause bloating, diarrhea, and dehydration. In rare cases, some osmotics may lead to kidney or heart disease. Osmotic laxatives include the brands Lactulose, which must be prescribed by a doctor, and Miralax, which can be found over the counter.

Stimulant Laxatives for IBS With Constipation

Stimulant laxatives usually contain a chemical called senna, which triggers muscles in the bowels to contract, moving stool through the bowel. While these laxatives work for occasional constipation, they are not recommended for long-term use.

"They should not be taken on a regular basis," says Schorr-Lesnick. "They may damage the nerve endings of the colon, and the patients could develop a tolerance for them so that they no longer work."

Stimulant laxatives are sold on drugstore shelves under many brand names, including Dulcolax and Ex-Lax Gentle Nature. Side effects can include diarrhea, upset stomach, vomiting, irritation, and stomach cramping.

To find out more about laxatives, talk with your doctor. Remember, there are other options for treatment of IBS with constipation. These include other medications, fiber supplements, dietary changes, stress management, behavioral therapy, and alternative therapies.

WebMD Medical Reference

Reviewed by Andrew Seibert, MD on October 06, 2012

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