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Sinusitis antibiotic interaction — GPhC CRA MCQ

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HardInfectionsSinusitis antibiotic interactionGPhC CRA

A 35-year-old woman presents a prescription for clarithromycin for sinusitis. Her record shows simvastatin 40 mg nightly and she reports previous severe muscle pain with erythromycin. What is the most appropriate alternative?

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Correct answer: C — Contact the prescriber to use a non-macrolide option if an antibiotic is indicated

Clarithromycin strongly inhibits CYP3A4 and can markedly increase simvastatin exposure, raising myopathy and rhabdomyolysis risk. The prior history of severe muscle symptoms with a macrolide increases concern. If an antibiotic is genuinely indicated, a non-macrolide option should be discussed with the prescriber. The pharmacist should not independently switch statin therapy.

Reference: BNF; NICE CKS