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Drug Interactions — EECC MCQ

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ModerateCardiac PharmacologyDrug InteractionsEECC

A 55-year-old man with chronic stable angina and LVEF 55% is started on ranolazine. He is also on simvastatin 40 mg, diltiazem 120 mg MR, and aspirin 75 mg. Which drug interaction is most clinically relevant?

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

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Correct answer: A — Ranolazine increases simvastatin levels via CYP3A4 inhibition, increasing rhabdomyolysis risk

Explanation lettering: B = shown as A · E = shown as B · A = shown as C · C = shown as D · D = shown as E

Ranolazine is a moderate inhibitor of CYP3A4. Simvastatin is metabolised by CYP3A4, and co-administration can significantly increase simvastatin levels, raising rhabdomyolysis risk. Per BNF, the simvastatin dose should not exceed 20 mg when used with moderate CYP3A4 inhibitors. Diltiazem itself also inhibits CYP3A4, compounding the interaction. Ranolazine has no clinically significant interaction with aspirin (B, E).

Reference: BNF: Ranolazine - Drug Interactions