The efficacy of rifaximin, a nonsystemic, gut-targeted antibiotic for reducing non–constipation-predominant irritable bowel syndrome (non-C IBS) symptoms, has been demonstrated in one phase 2b and two phase 3 randomized, double-blind, placebo-controlled trials.
However, detailed data about rifaximin safety and tolerability during treatment, and subsequent follow-up periods are lacking.
Dr Schoenfeld and colleagues from Michigan, USA assessed and determined the frequency of rifaximin and placebo adverse events in phase 2b and phase 3 non-C IBS trials.
A post hoc pooled safety analysis of the phase 2b, and phase 3 studies was performed.
|Patients receiving rifaximin and placebo had a similar incidence of drug-related adverse events|
|Alimentary Pharmacology & Therapeutics|
The researchers collected data on treatment and post-treatment adverse events.
The team followed up patients for 12 weeks and 10 weeks post-treatment in the phase 2b and phase 3 trials, respectively.
Patients receiving rifaximin and placebo had a similar incidence of drug-related adverse events, serious adverse events, drug-related adverse events resulting in study discontinuation, gastrointestinal-associated adverse events, and infection-associated adverse events.
The team observed no cases of Clostridium difficile colitis or deaths.
Dr Schoenfeld's team concludes, "The safety and tolerability profile of rifaximin during treatment and post-treatment was comparable to placebo."
"Future research should define the safety and tolerability profile, including risk of C. difficile colitis and microbial antibiotic resistance, with repeated courses of rifaximin in patients with non—constipation-predominant irritable bowel syndrome."