Rifaximin treatment for symptoms of irritable bowel syndrome.

OBJECTIVE: To evaluate the role of rifaximin in the treatment of symptoms associated with irritable bowel syndrome (IBS). DATA SOURCES: Clinical literature was accessed through MEDLINE (1990-September 2007) using the terms rifaximin, small intestinal bacterial overgrowth (SIBO), bacterial overgrowth, and irritable bowel syndrome. Additionally, references in publications identified in the search were reviewed for relevant information. STUDY SELECTION AND DATA EXTRACTION: All articles published in English identified from the data source were evaluated. Randomized clinical trials in adult populations were included. DATA SYNTHESIS: IBS is a common functional bowel disorder of unknown etiology. Some evidence suggests that symptoms are secondary to bacterial overgrowth in the small intestine. Rifaximin, a nonsystemic antibiotic that targets the gastrointestinal tract, has been evaluated in the treatment of SIBO. Six studies that evaluated rifaximin in either IBS, with or without documented SIBO, or SIBO alone, were reviewed. Significant symptom improvement was reported, and in some cases, correlated with reductions in hydrogen breath tests, suggesting successful treatment of bacterial overgrowth. Data are limited by controversial diagnostic techniques for SIBO, small sample sizes, the unpredictable course of the disorder, and variability in clinical trial methodology that prevents direct comparison.
CONCLUSIONS: Rifaximin offers a potential new therapeutic option for patients with refractory IBS. Larger, well-designed trials are necessary to elucidate the role of rifaximin in the treatment of this disorder.