Xifaxan (Rifaximin) for IBS-D and Non Constipation IBS

Xifaxan (rifaximin) is an antibiotic that is FDA-approved for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), as well as travelers' diarrhea, and to prevent hepatic encephalopathy. Xifaxan has also been used to treat small intestinal bacterial overgrowth (SIBO). 

Woman looking at prescription pill bottle
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How Does Xifaxan Work?

For ISB-D, Xifaxan is taken orally, three times a day for a two-week period. If adequate symptom relief is not achieved, the medication can be safely repeated for one to two more 14 day courses.

Xifaxan is not absorbed in the stomach and thus is thought to act on bacteria found in the small and large intestines. The non-absorption quality of Xifaxan results in minimal effects on the body as a whole.

Side Effects

Xifaxan is generally tolerated well. In clinical trials, adverse side effects tend to be in line with those of placebo. Minor side effects have been reported:

  • Constipation
  • Dizziness
  • Headache
  • Nausea and/or vomiting
  • Fatigue

Should you experience any of the following side effects when taking Xifaxan, you should contact your healthcare provider immediately:

  • Allergic symptoms, such as difficulty breathing; hives, itching or rash; or swelling of lips, face or tongue
  • Fever
  • Watery or bloody diarrhea

The FDA recommends that if the medication worsens your diarrhea symptoms, you should be evaluated for a  C. difficile infection.

Xifaxan should not be used if you have severe liver impairment, or if yuo have diarrhea due to pathogens other than E. coli.

Is Xifaxan Effective for IBS?

Clinical trials to date have shown that Xifaxan is more effective than placebo in alleviating symptoms of abdominal pain and improving stool consistency. Research to date has indicated that Xifaxan is well-tolerated and seems to be safe for short-term use. Some individuals may require more than one course of the medication in order to achieve desired results.

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2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Lembo A, Pimentel M, Rao SS, et al. Repeat Treatment With Rifaximin Is Safe and Effective in Patients With Diarrhea-Predominant Irritable Bowel Syndrome. Gastroenterology. 2016;151(6):1113-1121. doi:10.1053/j.gastro.2016.08.003

  2. FDA. Highlights of Prescribing Information. Xifaxan.

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