Metronidazole and vancomycin have been the primary treatment options for Clostridium difficile infection (CDI) for multiple decades. Now a recent study suggests that fidaxomicin may be the most effective treatment for providing a long-term cure. Fidaxomicin is a macrolide antibiotic, bactericidal against C. difficile. Fidaxomicin inhibits RNA synthesis by inhibiting sigma-dependent transcription of bacterial RNA polymerases and may act at the early stages of transcription.

CDI is diagnosed when a patient has the hallmark symptoms (usually diarrhea) and there is either a stool test positive for C. difficile toxins or detection of toxigenic C. difficile, or colonoscopic or histopathologic findings revealing pseudomembranous colitis. Illness from CDI typically occurs after use of antibiotics, most commonly in older adults who are being treated in hospitals or long-term care facilities. Estimates of cases of CDI in the US are around half a million annually. In 2014, the condition was responsible for $5.4 billion in healthcare costs.

In a recent study by Beinortas et al, published in The Lancet Infectious Diseases, several of the newer CDI treatments were compared, analyzed, and ranked. Of 23,004 studies screened, 24 trials were part of the analysis. In total, 5,361 patients and 13 separate treatments were included. The researchers rated the overall quality of evidence as moderate to low. The impressions gained from the study showed that fidaxomicin and teicoplanin were significantly better than vancomycin for sustained symptomatic cure of CDI. Except in the case of severe infection, fidaxomicin showed to be a better treatment option than vancomycin for all patients. Metronidazole should not be recommended for treatment of CID. Fidaxomicin could be considered as first-line therapy. As an additional note, fidaxomicin may reduce the risk for recurrent CDI because of its narrow spectrum compared with vancomycin.

The recently updated clinical practice guidelines for treatment of CDI published by the Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America favor a 10-day course of fidaxomicin or vancomycin rather than metronidazole for first-line therapy of mild/moderate CDI in adults. For new and updated information on pharmacotherapy such as those used to treat CDI, update or register your profile to receive email alerts and other critical drug information updates from PDR. You can also stay current by using the official PDR app, available now for free from your favorite app stores.