Abstract:
AIMS: To study the efficacy of rifaximin, a nonabsorbable antibiotic, in relieving chronic functional symptoms of bloating and flatulence. METHODS: Randomized double-blind placebo-controlled trial consisting of three 10-day phases: baseline (phase 1), treatment with rifaximin 400 mg b.i.d. or placebo (phase 2), and post-treatment period (phase 3). Primary efficacy variable was subjective global symptom relief at the end of each phase. A symptom score was calculated from a symptom diary. Lactulose H2-breath test (LHBT) was performed at baseline and end of study. RESULTS: One hundred and twenty-four patients were enrolled (63 rifaximin and 61 placebo). Baseline characteristics were comparable and none had an abnormal baseline LHBT. Rome II criteria were met in 58.7percent and 54.1percent, respectively. At the end of phase 2, there was a significant difference in global symptom relief with rifaximin versus placebo (41.3percentvs 22.9percent, p= 0.03). This improvement was maintained at the end of phase 3 (28.6percentvs 11.5percent, p= 0.02). Mean cumulative and bloating-specific scores dropped significantly in the rifaximin group (p andlt;0.05). Among patients with IBS, a favorable response to rifaximin was noted (40.5percentvs 18.2percent; p= 0.04) persisting by the end of phase 3 (27percentvs 9.1percent; p= 0.05). H2-breath excretion dropped significantly among rifaximin responders and correlated with improvement in bloating and overall symptom scores (p= 0.01). No adverse events were reported. CONCLUSIONS: Rifaximin is a safe and effective treatment for abdominal bloating and flatulence, including in IBS patients. Symptom improvement correlates with reduction in H2-breath excretion. Future trials are needed to examine the efficacy of long-term or cyclic rifaximin in functional colonic disorders. © 2006 by Am. Coll. of Gastroenterology.