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Metformin renal function — GPhC CRA MCQ

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HardEndocrine TherapeuticsMetformin renal functionGPhC CRA

A 64-year-old taking carbamazepine presents a prescription for apixaban after a new diagnosis of atrial fibrillation. What is the principal concern?

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Correct answer: A — Reduced apixaban exposure from enzyme induction

Carbamazepine strongly induces CYP3A4 and P-glycoprotein and can substantially reduce apixaban exposure, risking loss of stroke prevention. The prescription requires prompt review and selection of an anticoagulation strategy that can be used safely with the antiepileptic regimen. Simply increasing apixaban at the counter is inappropriate.

Reference: https://bnf.nice.org.uk/interactions/