Clostridium difficile-associated diarrhea is among the most serious nosocomial infections. It is most commonly treated with either vancomycin or metronidazole, but symptoms can recur following treatment with either of these drugs. A recent randomized trial compared fidaxomicin, a new macrocyclic antibiotic, vs. vancomycin in 629 patients (mean age 62 years, 56% female) with acute symptoms of C. difficile infection (mean 8 unformed stools per day). Patients were randomized to fidaxomicin 200 mg orally twice daily (plus placebo twice daily) vs. vancomycin 125 mg orally 4 times daily for 10 days. The primary outcome was clinical cure, defined as resolution of diarrhea (? 3 unformed stools for 2 consecutive days) with no need for additional therapy for at least 2 days after the end of treatment. There was no significant difference in the rate of clinical cure for fidaxomicin vs. vancomycin (88.2% vs. 85.8%, not significant) (level 1 [likely reliable] evidence). At follow-up 4 weeks after the end of treatment, the fidaxomicin group had a lower rate of C. difficile recurrence (15.4% vs. 25.3%, p = 0.005, NNT 10). There were no significant differences in adverse events. On January 24, 2011, the FDA granted a 6-month Priority Review of fidaxomicin (N Engl J Med 2011 Feb 3;364:422).
For more information, see the Clostridium difficile colitis topic in DynaMed.