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Irritable Bowel Syndrome (IBS) Health Center

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Alosetron for Irritable Bowel Syndrome


Generic Name Brand Name
alosetron Lotronex

How It Works

Alosetron slows the movement of stools through the bowels.

Why It Is Used

Alosetron is used to treat severe irritable bowel syndrome (IBS) in some women who have failed to respond to other treatments for severe diarrhea.

How Well It Works

Studies have shown that alosetron improves abdominal (belly) discomfort and reduces diarrhea and urgency of bowel movements.1

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call911or other emergency services right away if you have:

  • Trouble breathing.
  • Swelling of your face, lips, tongue, or throat.
  • Seizures.
  • Problems with muscle control or coordination, such as clumsiness or trembling.

Call your doctor right away if you have:

  • Hives.
  • Pain or tenderness in the belly.
  • A fever.
  • Stomach cramps.
  • Watery or bloody diarrhea.
  • Bleeding from the rectum.

Common side effects of this medicine include:

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Alosetron can cause a very serious side effect called ischemic colitis. This happens when blood flow to the large intestine is reduced. Symptoms of ischemic colitis include severe constipation, abdominal pain, rectal bleeding, and bloody diarrhea. If you have any of these symptoms, stop taking the medicine and call your doctor right away.

If you have ischemic colitis, you may need surgery to fix it. Some people who got ischemic colitis while taking alosetron died. Because of this dangerous side effect, alosetron is only used in women who have severe IBS with diarrhea and who have not had success with any other treatment for IBS. People taking alosetron must sign a consent form before starting to take the medicine, and only certain doctors can prescribe this medicine.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Advice for women

If you are pregnant, breast-feeding, or trying to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.


  1. Tack J (2006). Irritable bowel syndrome. In MM Wolfe et al., eds., Therapy of Digestive Disorders, 2nd ed., pp. 701-710. Philadelphia: Saunders Elsevier.

ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerArvydas D. Vanagunas, MD - Gastroenterology

Current as ofNovember 14, 2014

WebMD Medical Reference from Healthwise

Last Updated: November 14, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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