Experimental Drug May Treat Chronic Constipation

Aug. 10, 2011 -- Two studies show that a new kind of experimental medication relieves the pain and bloating of persistent constipation better than a placebo.

The studies, which are published in the New England Journal of Medicine, found that linoclotide relieved chronic constipation in up to 21% of patients, compared to as many as 6% who were helped on a placebo.

As many as one in five Americans suffer from chronic constipation, meaning that they have fewer than three bowel movements a week for at least three months. The condition is most common in women, the elderly, and people who suffer from irritable bowel syndrome.

There's currently one prescription drug, Amitiza, that's widely used for treating chronic constipation.

A host of other over-the-counter remedies haven't been well studied in patients for whom constipation has become a long-term problem.

Study researcher Anthony J. Lembo, MD, a gastroenterologist at Beth Israel Deaconess Medical Center in Boston, says linoclotide is unique because it stimulates cells in the lining of the bowel to produce secretions that help draw more fluid into the gut. The fluid helps to soften stool and speed its passage.

"It won't help everybody, of course. Not all patients have their symptoms relieved," Lembo tells WebMD. "There are a lot of different causes for constipation."

Investigating a New Medication for Chronic Constipation

To test the drug, researchers recruited more than 1,200 adults in the U.S. and Canada who had histories of chronic constipation along with symptoms like straining, lumpy or hard stools, and a feeling of incomplete evacuation.

There were roughly 600 patients in each study.

In both trials, people were randomly assigned to one of three groups: those on a lower daily dose of linoclotide, those on a higher dose, and those who were unknowingly taking a placebo.

They were asked to take their capsules 30 minutes before breakfast each day for 12 weeks.

Researchers considered the patients successfully treated if they'd had at least three complete bowel movements each week plus at least one more bowel movement each week than they had averaged going into the study for nine out of 12 weeks.

In the first study, 21% of the patients on the low dose of the drug and 19% of patients on the high dose of the drug achieved that goal, compared to 3% who were taking the placebo.

In the second study, 16% on the low dose and 21% on the higher dose met that target, compared to 6% who were taking the placebo.

Stated another way, about six to 10 people would need to take the drug for one person to see a benefit.

The most commonly reported side effect was diarrhea, which affected 14% to 16% of patients on the high and low doses and about 5% who were taking the placebo.