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Warfarin and miconazole oral gel — GPhC CRA MCQ

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ModerateDrug InteractionsWarfarin and miconazole oral gelGPhC CRA

A 75-year-old man stable on warfarin asks to buy miconazole oral gel for denture-related oral thrush. His last INR was 2.4 and he has no bleeding. What is the most important interaction to flag?

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Correct answer: B — Miconazole can markedly increase warfarin effect and bleeding risk.

Miconazole, including oral gel, can significantly increase anticoagulant effect in patients taking warfarin. The interaction can cause serious bleeding and should be avoided or managed with prescriber involvement. An alternative antifungal strategy should be considered.

Reference: BNF; MHRA Drug Safety Update