Antibiotic therapy for irritable bowel syndrome

Lacy, 2021

At the time of writing, 2 large randomised controlled trialsPimentel, 2011 have shown modest efficacy of rifaximin (a poorly absorbable antibiotic) at relieving global symptoms of IBS (eg bloating, flatulence) in patients with diarrhoea-predominant IBS. The mechanism of action and predictors of response are not clear, although some studies have suggested that a positive lactulose breath test is associated with a higher likelihood of responseBae, 2015.

For patients with mixed bowel habits or diarrhoea-predominant IBS, use:

rifaximin 500 or 550 mg orally, 8-hourly for 14 days1 rifaximin rifaximin rifaximin

Rifaximin therapy is associated with high relapse rates; retreatment with up to 2 subsequent 14 day courses may improve efficacyLembo, 2016Fodor, 2019Li, 2016.

Rifaximin is well tolerated and, at the time of writing, there is little evidence to suggest that short-term use leads to antimicrobial resistancePimentel, 2017.

1 At the time of writing, rifaximin is not approved by the Australian Therapeutic Goods Administration (TGA) for IBS. See the TGA website for current information. Rifaximin 500 mg is available through compounding pharmacies.Return