Rifaximin versus Other Antibiotics in the Primary Treatment and Retreatment of Bacterial Overgrowth in IBS

Purpose Previous studies demonstrate improvement in IBS after antibiotic therapy, with the greatest efficacy seen with the antibiotic, rifaximin. The purpose of this study was to compare the efficacy of rifaximin in both the treatment and retreatment of IBS. Methods A retrospective chart review was conducted on Rome I-positive IBS patients. Charts were reviewed to evaluate all antibiotic treatments (rifaximin, neomycin, doxycycline, amoxicillin/clavulanate, and ciprofloxacin), even those predating 1 July 2004. Data collection included symptoms, breath test results (pre- and post-treatment), antibiotics used, and clinical response to individual antibiotic treatments before and after rifaximin availability in the USA. Results Out of 98 eligible charts, 84 patients received one course of rifaximin. Fifty of these (60%) had a follow-up breath test. Among these, 31 (62%) were clinical responders and 19 (38%) were nonresponders. Of 31 responders, 25 (81%) had a normal follow-up breath test compared with only 3 of the 19 nonresponders (16%) (P < 0.001). Of participants given rifaximin, 69% (58 out of 84) had a clinical response compared with only 38% (9 out of 24) with neomycin (P < 0.01) and 44% (27 out of 61) with all non-rifaximin antibiotics (P < 0.01). Rifaximin was used as retreatment on 16 occasions, and all patients improved. Conclusions Rifaximin is more effective than other antibiotics in the treatment and retreatment of IBS.