American Board of Family Medicine (ABFM) Practice Exam 2025 – The All-In-One Guide to Master Your Certification!

The most appropriate intravenous antibiotic for a patient with severe Clostridioides difficile infection not improving with oral vancomycin is metronidazole. In cases of severe C. difficile infection, particularly when there is a lack of response to oral vancomycin, metronidazole is often recommended as an adjunctive treatment option.

Metronidazole is effective against anaerobic bacteria and is commonly used for treating C. difficile infections, especially in cases where the patient is not responding to oral routes or has significant gastrointestinal involvement. Using metronidazole intravenously can provide systemic coverage while still targeting the infection source effectively.

In general practice, the combination of both oral vancomycin and intravenous metronidazole can be useful in treating patients with severe C. difficile infection, particularly when there is a risk of complications or if the patient cannot tolerate oral medications.

This choice is supported by treatment guidelines that suggest considering metronidazole in cases of severe refractory C. difficile infection. Other options like ciprofloxacin and meropenem are not typically indicated for treating C. difficile infections specifically due to their differing mechanisms of action and resistance patterns, making them less appropriate in this scenario. Moreover, continuing vancomycin would not