Rifaximin Is Effective for the Treatment of Clostridium difficile-Associated Diarrhea: Results of an Open-Label Pilot Study.

Objectives. This open-label trial assessed the efficacy and safety of rifaximin as first-line therapy in hospitalized patients with Clostridium difficile-associated diarrhea (CDAD). Methods. We enrolled thirteen patients who had a confirmed diagnosis of CDAD characterized by ≥3 unformed stools/day and positive C. difficile toxin assay. Those patients received rifaximin 400 mg three times daily for 10 days. Resolution of symptoms, repeat assay 10 days after treatment, and followup for recurrence were assessed. Results. Eight patients completed the study, and all reported symptom resolution during treatment. Mean time to last unformed stool was 132 h ± 42.5 h. Seven patients had no relapse by week 2 and in longer followup (median 162 days). One patient had recurrent CDAD during a repeat hospitalization. Conclusions. Rifaximin was effective and safe as first-line treatment for CDAD and did not result in recurrence in most patients.