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Simvastatin and clarithromycin — GPhC CRA MCQ

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ModerateDrug InteractionsSimvastatin and clarithromycinGPhC CRA

A patient taking simvastatin 40 mg at night is prescribed clarithromycin for pneumonia. They have previously had statin-associated muscle pain. What is the most appropriate action?

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Correct answer: D — Contact the prescriber because clarithromycin increases simvastatin myopathy risk

Clarithromycin inhibits CYP3A4 and can increase simvastatin concentrations, raising myopathy and rhabdomyolysis risk. The prescriber should consider an alternative antibiotic or temporarily withholding the statin, depending on clinical context. Changing the time of dosing does not remove the interaction. Muscle symptoms should be taken seriously.

Reference: BNF