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Macrolide and statin interaction — GPhC CRA MCQ

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ModerateInfectionsMacrolide and statin interactionGPhC CRA

A patient taking simvastatin 40 mg at night is prescribed clarithromycin for pneumonia. The patient asks if he can continue every medicine as usual. What is the most important interaction to flag?

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Correct answer: A — Increased risk of statin toxicity and rhabdomyolysis

Clarithromycin inhibits CYP3A4 and can substantially increase simvastatin exposure. This increases the risk of myopathy and rhabdomyolysis. The prescriber should be contacted about withholding simvastatin or using a different antibiotic where appropriate. The patient should be advised to report muscle pain, weakness or dark urine.

Reference: BNF; NICE CKS