The Rise and Fall of Metronidazole for Clostridium difficile Infection.

Clostridium difficile is posing urgent health threats. Older studies have shown that metronidazole and vancomycin are equally effective in the treatment of Clostridium difficile infection (CDI). Given its inexpensive cost and low propensity to select antimicrobial resistant organisms, metronidazole became rapidly the drug of choice despite its pharmacokinetic limitations in the treatment of CDI. However, newer studies demonstrated that metronidazole is inferior to vancomycin, prompting clinicians to change their long-standing position on using metronidazole for mild to moderate infections and on reserving vancomycin for severe infections. Moving forward, metronidazole will fall out of favor in the treatment of CDI.