Summary of possible benefits and harms

How well does colesevelam work?

One study compared colesevelam with a 'dummy' tablet (known as placebo) in 24 women with irritable bowel syndrome and diarrhoea as a main symptom. Four of the women were thought to have bile acid malabsorption. In the 24 women, colesevelam did not reduce the time it took for a meal to pass through the digestive system compared with the dummy tablet. Reducing this time could reduce diarrhoea. Colesevelam did make it easier to pass stools, but did not reduce the number of stools passed each day or the stool consistency (if stools were watery or hard) compared with the dummy tablet.

Another study looked at how well colesevelam worked in 45 people who had received treatment for cancer. These people had symptoms of bile acid malabsorption for at least 3 months. Out of the 45 people, 30 had previously tried colestyramine, but it had not helped. Colesevelam reduced how often and how urgently people had to empty their bowels, bowel incontinence (involuntary passage of stools) and tummy pain.

Another study looked at how well colesevelam worked for treating bile malabsorption, but included only 5 people. All 5 had previously tried colestyramine but were not able to take it. In these 5 people, colesevelam reduced diarrhoea.

What are the possible harms or side effects?

The most common side effects of colesevelam (seen in at least 1 in every 10 people) are flatulence (wind) and constipation. Other side effects include headache, feeling sick and vomiting, diarrhoea, indigestion, abnormal stools, tummy pain and bloating (seen in between 1 in every 100 people and 1 in every 10 people), difficulty swallowing, muscle pain (seen in between 1 in every 1000 people and 1 in every 100 people) and pancreatitis (inflammation of the pancreas, seen in fewer than 1 in every 10,000 people).

Colesevelam may reduce how well some other drugs are absorbed. Therefore, colesevelam should be taken at least 4 hours before or at least 4 hours after other medication.

Please note that the results of the research studies only indicate the benefits and harms for the population in the studies. It is not possible to predict what the benefits and harms will be for an individual patient being treated with colesevelam.