Rifaximin dose‐finding study for the treatment of small intestinal bacterial overgrowth

Abstract

Few controlled studies assessing choice and duration of antibiotic therapy for small intestinal bacterial overgrowth are available. To assess efficacy, safety and tolerability of different doses of rifaximin, a broad spectrum non-absorbable antibiotic, for intestinal bacterial overgrowth eradication. We enrolled 90 consecutive patients affected by small intestinal bacterial overgrowth. The presence of small intestinal bacterial overgrowth was based on the occurrence of a rise of H2 values >12 p.p.m. above the basal value after 50 g glucose ingestion. Patients were randomized in three 7-day treatment groups: rifaximin 600 mg/day (group 1); rifaximin 800 mg/day (group 2) and rifaximin 1200 mg/day (group 3). Glucose breath test was reassessed 1 month after the end of therapy. Compliance to the treatment and incidence of side-effects were also evaluated. No drop-outs were observed in the three groups. Glucose breath test normalization rate was significantly higher in group 3 (60%) with respect to group 1 (17%; P < 0.001) and group 2 (27%, P < 0.01). No significant differences in patient compliance and incidence of side-effects were found among groups. Higher doses of rifaximin lead to a significant gain in terms of therapeutic efficacy in small intestinal bacterial overgrowth eradication without increasing the incidence of side-effects.