An Antibiotic for Irritable Bowel Syndrome?

Antibiotic use has been suggested to treat patients with irritable bowel syndrome (IBS), particularly for cases that are difficult to treat or are accompanied by bloating. One antibiotic that has shown efficacy in small IBS studies is rifaximin (JW Gastroenterol Oct 16 2006), a minimally absorbed, oral agent that has activity against gram-positive and gram-negative bacteria, anaerobes, and Clostridium difficile and is indicated for Escherichia coli–related travelers' diarrhea and reduction of risk for hepatic encephalopathy.

To further test whether rifaximin can relieve IBS symptoms, investigators conducted two industry-supported, identically designed, double-blind, randomized, placebo-controlled trials involving a total of 1260 patients who…