The Effect of a Nonabsorbed Oral Antibiotic (Rifaximin) on the Symptoms of the Irritable Bowel Syndrome

A Randomized Trial

17 October 2006 | Volume 145 Issue 8 | Pages 557-563

Background: Alterations in gut flora may be important in the pathophysiology of the irritable bowel syndrome (IBS).

Objective: To determine whether the nonabsorbed antibiotic rifaximin is more effective than placebo in reducing symptoms in adults with IBS.

Design: Double-blind, randomized, placebo-controlled study.

Setting: 2 tertiary care medical centers.

Participants: 87 patients who met Rome I criteria for IBS and were enrolled from December 2003 to March 2005.

Interventions: Participants who met enrollment criteria were randomly assigned to receive 400 mg of rifaximin 3 times daily for 10 days (n = 43) or placebo (n = 44). Eighty participants completed rifaximin therapy or placebo, and follow-up data were available for at least 34 participants per study group at any time point thereafter.

Measurements: A questionnaire was administered before treatment and 7 days after treatment. The primary outcome was global improvement in IBS. Patients were then asked to keep a weekly symptom diary for 10 weeks.

Results: Over the 10 weeks of follow-up, rifaximin resulted in greater improvement in IBS symptoms (P = 0.020). In addition, rifaximin recipients had a lower bloating score after treatment.

Limitations: The major limitations of the study were its modest sample size and short duration and that most patients were from 1 center.

Conclusions: Rifaximin improves IBS symptoms for up to 10 weeks after the discontinuation of therapy.

Editors' Notes Context Few trials have evaluated the effects of antibiotics on symptoms of the irritable bowel syndrome (IBS). Contribution In this double-blind trial, 87 patients with IBS were randomly assigned to either rifaximin (400 mg 3 times daily) or placebo for 10 days. Over a 10-week follow-up period, the rifaximin recipients reported global improvements in overall symptoms and less bloating more frequently than the placebo recipients. No major differences in abdominal pain, diarrhea, or constipation were observed between the groups. Cautions The duration of therapy and follow-up was short. Implications Rifaximin may improve some symptoms in some patients with IBS. —The Editors

 

Author and Article Information

From the Cedars-Sinai Medical Center, Burns and Allen Research Institute, and University of California, Los Angeles, Geffen School of Medicine, Los Angeles, California, and University of Chicago, Chicago, Illinois.

Acknowledgments: The authors thank Tess Constantino, RN, and Vicki Lees-Kim, RN, for their assistance with patient coordination; Robert Wade for his vast experience with lactulose breath testing; and Dr. Soumya Chatterjee for his assistance in auditing the data. In addition, they thank the Beatrice and Samuel A. Seaver Foundation, which has been a gracious supporter of the work on gut bacteria and IBS.

Grant Support: By Salix Pharmaceuticals.

Potential Financial Conflicts of Interest:Consultancies: M. Pimentel (Novartis, Chugai Pharmaceutical, Promethus, Romark, Salix Pharmaceuticals); Honoraria: M. Pimentel (Novartis, Salix Pharmaceuticals); Grants received: M. Pimentel (Salix Pharmaceuticals); Patents received: M. Pimentel (Cedars-Sinai Medical Center); Patents pending: M. Pimentel (Cedars-Sinai Medical Center). Cedars-Sinai Medical Center has a licensing agreement with Salix Pharmaceuticals.

Request for Single Reprints: Mark Pimentel, MD, Cedars-Sinai Medical Center, 8730 Alden Drive, Suite 225E, Los Angeles, CA, 90048; e-mail, pimentelm{at}cshs.org.

Current Author Addresses: Dr. Pimentel, Ms. Park, and Ms. Kong: Cedars-Sinai Medical Center, 8730 Alden Drive, Suite 225E, Los Angeles, CA 90048.

Dr. Mirocha: Biostatistics Core, Research Institute and General Clinical Research Center and Cardiothoracic Surgery, Cedars-Sinai Medical Center, Room 101, Atrium Annex Building, 8700 Beverly Boulevard, Los Angeles, CA 90048.

Dr. Kane: University of Chicago, 5841 South Maryland Avenue, MC 4076, Chicago, IL 60637.

Author Contributions: Conception and design: M. Pimentel, S. Park, Y. Kong.

Analysis and interpretation of the data: M. Pimentel, J. Mirocha.

Drafting of the article: M. Pimentel, S. Park, S.V. Kane.

Critical revision of the article for important intellectual content: M. Pimentel, S. Park, J. Mirocha, S.V. Kane, Y. Kong.

Final approval of the article: M. Pimentel, J. Mirocha, Y. Kong.

Provision of study materials or patients: M. Pimentel, S.V. Kane.

Statistical expertise: M. Pimentel, J. Mirocha.

Obtaining of funding: M. Pimentel.

Administrative, technical, or logistic support: M. Pimentel, S. Park, Y. Kong.

Collection and assembly of data: M. Pimentel, S. Park, Y. Kong.

ClinicalTrials.gov Identifier: NCT00259155.

Read all Rapid Responses

The Need to Define The Target of Antibiotic Therapy in IBS Patients: Small Bowel or Colonic Flora?

Michele Di Stefano, et al.

Annals Online, 18 Dec 2006 [Full text]