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Anticholinergics (Antispasmodics) for Irritable Bowel Syndrome


Generic NameBrand Name
dicyclomineBentyl, Anaspaz, Cystospaz, Levsin
hyoscyamineBentyl, Anaspaz, Cystospaz, Levsin

How It Works

Antispasmodics relax the smooth muscles of the gut, helping to prevent or relieve painful cramping spasms in the intestines. These medicines can be taken as needed for cramps. They can also be taken 30 to 45 minutes before meals that you expect might cause symptoms or when symptoms would be inconvenient or bothersome.

Why It Is Used

Antispasmodics are used to relieve cramps or spasms of the stomach, intestines, or bladder.

Do not use antispasmodics if you suffer from:

How Well It Works

Some studies suggest that antispasmodics improve symptoms of IBS and reduce pain. But studies on antispasmodics available in the United States have been less promising. Some studies show a benefit, and some don't.1

Side Effects

Side effects may include drowsiness, dry mouth, blurred vision, or an inability to urinate. Antispasmodics may make constipation—often a main symptom of IBS—worse.

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

What To Think About

If constipation is your main symptom, antispasmodics may not work for you. In some cases, use of antispasmodics can make constipation worse.

If you are pregnant, ask your doctor about taking antispasmodics. Some studies have suggested that some antispasmodics can increase the heartbeat of a fetus, and that some are related to birth defects, though they have not been proved to cause these defects.

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



  1. American College of Gastroenterology (2009). An evidence-based systematic review on the management of irritable bowel syndrome. American Journal of Gastroenterology, 104(Suppl 1): S8–S35.


ByHealthwise Staff
Primary Medical ReviewerE. Gregory Thompson, MD - Internal Medicine
Specialist Medical ReviewerArvydas D. Vanagunas, MD - Gastroenterology
Last RevisedApril 26, 2012

eMedicineHealth Medical Reference from Healthwise

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