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Fiber, Antispasmodic Agents, and Peppermint Oil for Irritable Bowel Syndrome

All these agents were more effective than placebo for patients with IBS.

Irritable bowel syndrome (IBS), which affects 5% to 20% of the population, is a chronic gastrointestinal disorder characterized by relapsing and remitting bouts of abdominal pain and altered bowel movements. Evidence suggests that fiber, antispasmodic agents, and peppermint oil all are effective for treating patients with IBS. In this systematic review and meta-analysis, investigators evaluated the efficacy of these agents.

In 12 randomized controlled trials (591 patients), fiber was compared with placebo or no treatment; in 22 trials (1778 patients), antispasmodic agents were compared with placebo; and in 4 trials (392 patients), peppermint oil was compared with placebo. Persistent IBS symptoms were significantly less common in patients treated with fiber (relative risk, 0.87), antispasmodic agents (RR, 0.68), and peppermint oil (RR, 0.43) than with placebo. The number of patients needed to treat to prevent 1 patient from experiencing persistent IBS symptoms was 11 for fiber, 5 for antispasmodic agents, and 2.5 for peppermint oil.

Comment: Fiber, antispasmodic agents, and peppermint oil are more effective than placebo for alleviating IBS. Among the fiber preparations, benefit was limited to ispaghula husk (psyllium; Metamucil). Among the antispasmodic agents, only otilonium and hyoscine showed consistent benefit. (Otilonium is unavailable in the U.S.) Hyoscine (scopolamine), a belladonna alkaloid, is available in pill and patch forms. Notably, a similar drug, hyoscyamine (Levsin), is commonly used to treat IBS. Peppermint oil appears to be a promising treatment and is available over the counter; in the trials, doses of peppermint oil ranged from 187 mg to 225 mg, and it was given two to four times daily. These new data are welcome, especially because prescription IBS drugs (e.g., Zelnorm) have been withdrawn from the market recently.

— Paul S. Mueller, MD, MPH, FACP

Published in Journal Watch General Medicine December 4, 2008

Citation(s):

Ford AC et al. Effect of fibre, antispasmodics, and peppermint oil in the treatment of irritable bowel syndrome: Systematic review and meta-analysis. BMJ 2008 Nov 13; 337:a2313. (http://dx.doi.org/10.1136/bmj.a2313)

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