All About Bentyl for IBS

female pharmacist with patient
Ariel Skelley/Blend Images/Getty Images

Bentyl (dicyclomine) is a medication for the treatment of irritable bowel syndrome (IBS). Bentyl is labeled as an antispasmodic medication and thus is thought to be helpful in reducing intestinal spasms that can contribute to the abdominal pain and motility problems that are hallmark symptoms of IBS. However, due to the risk of constipation, Bentyl might not be right for patients who suffer from constipation predominant IBS (IBS-C).

And because of its side effect profile, Bentyl is no longer frequently prescribed.

Bentyl is classified as an anticholinergic medication because it reduces the effect of the neurotransmitter acetylcholine within the body. This diminished action of acetylcholine results in a decrease in muscle spasms and secretion of mucus. Unfortunately, in addition to bringing about IBS symptom relief, Bentyl's effect on the action of acetylcholine also can bring about a whole host of unwanted side effects.

Side Effects of Bentyl

As stated above, the anticholinergic effect of Bentyl can affect systems throughout the body. The most commonly reported side effects include:

  • Blurred vision
  • Constipation
  • Decreased sweating
  • Decreased urination
  • Dizziness
  • Dry mouth

Bentyl may also cause more serious side effects, such as confusion or falling. If you experience any unusual or concerning side effects, contact your doctor. Shoule you experience any severe side effects, seek immediate medical attention.

Is Bentyl Effective?:

Although Bentyl is frequently prescribed medication for IBS, there is a glaring lack of research as to its effectiveness. I was able to find one clinical study that assessed the effectiveness of Bentyl in reducing symptoms. The results indicated that Bentyl was superior to a placebo in reducing abdominal pain and tenderness, and improving bowel functioning and overall IBS symptoms.

The downside was that approximately 68% of the patients experienced unpleasant anticholinergic side effects.

How to Take Bentyl

Bentyl comes in many forms - as a capsule, tablet or syrup. It is always taken by mouth. Be sure to follow your doctor's instructions carefully as to when to take it. Your doctor may start you off at a low dose and then gradually increase your dosage.

Typically, Bentyl is to be taken several times during the day at spaced out intervals. Your doctor may recommend that you take Bentyl 30 to 60 minutes before eating.


"Dicyclomine" Medline Plus Accessed February 1, 2016.

Ford, A., "American College of Gastroenterology Monograph on the Management of Irritable Bowel Syndrome and Chronic Idiopathic Constipation" American Journal of Gastroenterology 2014 109:S2-S26.

Page, J. & Dirnberger, G. "Treatment of the irritable bowel syndrome with Bentyl (dicyclomine hydrochloride)" Journal of Clinical Gastroenterology 1981 3:153-156.

Trinkley, K. & Nahata M. "Medication Management of Irritable Bowel Syndrome" Digestion 2014 89:253-267.

Continue Reading