Rifaximin for the treatment of irritable bowel syndrome.

Few therapeutic options are available for irritable bowel syndrome (IBS). Lubiprostone is approved by the FDA for IBS with constipation, and alosetron in IBS with diarrhea (IBS-D). It has been proposed that alterations in the bowel microflora may play a role in the pathophysiology of IBS, and that modulation of the microflora holds therapeutic potential. Rifaximin is a nonsystemic antibiotic that has shown efficacy in IBS. This narrative review covers the treatment options available for IBS-D and focuses on rifaximin. Rifaximin pharmacodynamics, clinical pharmacology and results of clinical studies from proof of concept to the latest Phase III and retreatment studies in IBS are summarized. Challenges to rifaximin use, safety issues and regulatory data are also discussed. The evidence supports rifaximin as an emerging treatment for IBS. Strategies for appropriate patient selection need to be further developed, and continued efficacy of rifaximin over repeated treatment courses needs to be better characterized.