Oral vancomycin replaces metronidazole as first-line treatment for Clostridioides difficile in new guidelines from infectious diseases physicians.

In the first changes since 2016, the Australasian Society for Infectious Diseases (ASID) cited a head-to-head randomised controlled trial suggesting metronidazole was inferior to vancomycin for treatment of C. difficile infection (CDI).

Use of metronidazole was based on unblinded studies, it said.

The guidelines, published in the Internal Medicine Journal this week, said vancomycin (oral or enteral but not IV) was the preferred primary therapy for both adults and children with first-episode non-severe or severe disease.