skip to main content

Simvastatin and clarithromycin — GPhC CRA MCQ

Instant feedback + full explanation. One question, done properly.

HardDrug InteractionsSimvastatin and clarithromycinGPhC CRA

A 72-year-old man taking simvastatin 40mg nightly is prescribed clarithromycin 500mg twice daily for pneumonia. He has CKD stage 3 and reports previous statin muscle pain. What is the most important interaction to flag?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Ask the prescriber to review the macrolide or temporarily withhold simvastatin

Clarithromycin inhibits CYP3A4 and can increase simvastatin exposure, raising myopathy and rhabdomyolysis risk. CKD and previous muscle symptoms increase clinical concern. The prescriber should consider an alternative antibiotic or advise temporary statin interruption as appropriate. Changing administration time will not remove the metabolic interaction.

Reference: BNF