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Clarithromycin and simvastatin — GPhC CRA MCQ

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ModerateInfectionsClarithromycin and simvastatinGPhC CRA

A 67-year-old man taking simvastatin 40mg nightly is prescribed clarithromycin 500mg twice daily for pneumonia. He has no statin intolerance and normal renal function. What is the most important interaction to flag?

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Correct answer: A — Clarithromycin can increase simvastatin exposure and myopathy risk

Clarithromycin strongly inhibits metabolism of simvastatin, increasing the risk of myopathy and rhabdomyolysis. The prescriber should consider an alternative antibiotic or temporarily withholding the statin. The patient should be counselled to report muscle pain, weakness or dark urine.

Reference: BNF