What is the risk with Rifaximin?

While no one knows how quickly resistance of gut microbes will develop in response to rifaximin, the likelihood of resistance is high and this should temper its usage (J Clin Gastroenterol 2013; 47: 205-11).

Rifaximin, along with other antibiotics, has been shown to relieve symptoms in certain cohorts of irritable bowel syndrome (IBS) patients.  Generally, the results of these studies have been modest (see below); however, because it is a “gut specific” antibiotic with minimal systemic absorption (<1%) and therefore minimal adverse effects, it has been considered a reasonable and safe treatment by many.  It has been useful as well for traveler’s diarrhea, hepatic encephalopathy, and colonic diverticular disease.  With regard to IBS, the major concern is that this is a chronic disorder and repeated usage will result in antimicrobial resistance.

Resistance to rifaximin could result in serious consequences if it provoked a class effect resistance.  Rifaximin belongs to the rifamycin class of antibiotics which treat numerous diseases including tuberculoses, meningococcal disease, Clostridium difficile, and methicillin-resistance Staphylococcus aureus.

Given the limited number of suitable alternatives and emerging resistance patterns, wise stewardship of our current antibiotics is essential, though unlikely.  It is not difficult to foresee a rise in mortality from some infectious problems that are easily treated currently.

Related references:

  • -JPGN 2011; 52: 382.  Double-blind, placebo-controlled study of rifaximin in children with RAP.  n=75.  Not effective in this study.
  • -NEJM 2011; 364: 22 (pg 81-editorial). About 10% improvement over placebo in pts with IBS-D. Effects lasted up to 3 months.
  • -DDW 2010, 475 abstract. Target 1 & Target 2. n=623, n=637. Relief of IBS in ~41% vs ~32% placebo. 550mg TID x 14days.

Related blog posts:

3 thoughts on “What is the risk with Rifaximin?

  1. On the bright side, I never can get rifaximin covered by insurance except where concern for hepatic encephalopathy or with children with sgs and significant sbbo. That being said, I have had decent success with metronidazole + flor a stor for empiric treatment of suspected sbbo in otherwise normal children.

  2. Pingback: FDA Approves Rifaximin and Eluxadoline for IBS-D | gutsandgrowth

  3. Pingback: Clinically Useful Biomarkers for Irritable Bowel Syndrome? | gutsandgrowth

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