Fidaxomicin, a new treatment for Clostridium difficile infections.

Clostridium difficile is currently the most important cause of infectious diarrhea in the United States. Fidaxomicin, a macrolide antibiotic, was recently approved for treatment of C. difficile infections (CDIs). In vitro studies demonstrate that fidaxomicin has a narrow spectrum of activity against C. difficile with minimal effect on the gut flora. Clinical trials indicate that fidaxomicin is as effective as vancomycin for treatment of CDI with fewer recurrences. Additionally, fidaxomicin has minimal systemic absorption with few adverse side effects. Thus, fidaxomicin is an attractive new alternative for treatment of CDI.