This information is for people who have irritable bowel syndrome. It tells you about loperamide, a treatment used for irritable bowel syndrome. It is based on the best and most up-to-date research.
Does it work?
We're not sure. This drug may help with diarrhoea, but we need more research to know if it helps other symptoms of irritable bowel syndrome (IBS).
What is it?
Loperamide is often used as treatment when diarrhoea is the main symptom of IBS. People sometimes take loperamide for a short time to relieve pain and reduce diarrhoea if their symptoms flare up.
Your doctor can prescribe loperamide, or you can buy anti-diarrhoea medicine containing loperamide in a pharmacy. One brand is Imodium, but you can probably find cheaper own-brand versions.
How can it help?
Taking loperamide may help to make your stools more solid and reduce the number of times you need to go to the toilet.  It may also make your need for the toilet less urgent.
How does it work?
Loperamide is a type of anti-diarrhoea drug that works by stopping your bowels going into spasm. This should reduce your need for the toilet and the feeling that you have to go urgently.
Can it be harmful?
People who took loperamide were likely to have more pain in their abdomen at night.  But they got less pain if the dose was split and taken twice a day.
You might get some side effects if you take loperamide, such as: 
How good is the research on loperamide?
We found one summary of the research ( systematic review) that looked at five studies in people with IBS.  Overall, it found that loperamide can help with diarrhoea and the feeling of urgently needing the toilet. But the studies were poor-quality. Some were small, and most were done more than 10 years ago.
We need more research on loperamide to know how helpful it is for people with IBS.
A systematic review is a thorough look through published research on a particular topic. Only studies that have been carried out to a high standard are included. A systematic review may or may not include a meta-analysis, which is when the results from individual studies are put together.
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