A patient receiving clindamycin develops C. difficile–associated diarrhea. Treatment should consist of?

• A. Continuing clindamycin and IV vancomycin
• B. Discontinuing clindamycin and waiting to see if the original infection clears
• C. Stopping clindamycin, choosing a drug of second choice for the original infection, and starting oral metronidazole
• D. Hospitalizing the patient, finishing the course of clindamycin, and starting IV fluids

Answer: (C)

When C. difficile infection follows antibiotic use, the priority is to remove the trigger and treat the infection directly. Stopping the antibiotic that disrupted the gut flora allows the normal defenses to recover, reducing toxin production. At the same time, you treat the C. difficile with an agent active against the organism delivered to the gut.

In this scenario, that means discontinue the clindamycin, switch the patient to a different drug for the original infection, and start an oral anti-C. difficile therapy such as metronidazole for mild to moderate disease. Continuing the inciting antibiotic would keep fueling the infection, and simply waiting for the original infection to clear does not address the toxin-mediated diarrhea. Oral therapy targets the colonic infection more effectively than IV antibiotics, and while supportive care like IV fluids is important, it’s not sufficient without stopping the trigger and providing targeted anti-C. difficile treatment.