High dosage rifaximin for the treatment of small intestinal bacterial overgrowth


Dr. A. Gasbarrini, Internal Medicine and Angiology, Catholic University of Sacred Heart, Gemelli Hospital, Largo A. Gemelli, 8; 00168 Rome, Italy.
E-mail: angiologia@rm.unicatt.it




Rifaximin is a broad spectrum non-absorbable antibiotic used for treatment of small intestinal bacterial overgrowth. Doses of 1200 mg/day showed a decontamination rate of 60% with low side-effects incidence.


To assess efficacy, safety and tolerability of rifaximin 1600 mg with respect to 1200 mg/day for small intestinal bacterial overgrowth treatment.


Eighty consecutive small intestinal bacterial overgrowth patients were enrolled. Diagnosis of small intestinal bacterial overgrowth based the clinical history and positivity to H2/CH4 glucose breath test. Patients were randomized in two 7-day treatment groups: rifaximin 1600 mg (group 1); rifaximin 1200 mg (group 2). Glucose breath test was reassessed 1 month after. Compliance and side-effect incidence were also evaluated.


One drop-out was observed in group 1 and two in group 2. Glucose breath test normalization rate was significantly higher in group 1 with respect to group 2 both in intention-to-treat (80% vs. 58%; P < 0.05) and per protocol analysis (82% vs. 61%; P < 0.05). No significant differences in patient compliance and incidence of side effects were found between groups.


Rifaximin 1600 mg/day showed a significantly higher efficacy for small intestinal bacterial overgrowth treatment with respect to 1200 mg with similar compliance and side-effect profile.