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Rate-control medicine interaction — GPhC CRA MCQ

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HardCardiovascular TherapeuticsRate-control medicine interactionGPhC CRA

A 72-year-old man takes bisoprolol 7.5mg daily for atrial fibrillation. A new prescription arrives for diltiazem modified-release 180mg daily after a cardiology letter. His pulse at collection is 48 beats/minute and he feels dizzy. What is the most important interaction to flag?

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Correct answer: D — Diltiazem with bisoprolol may cause bradycardia and heart block

Both diltiazem and beta-blockers slow atrioventricular conduction and reduce heart rate. The patient's bradycardia and dizziness make the interaction clinically important at the point of supply. Prescriber clarification is needed before adding diltiazem. The other proposed outcomes do not match the pharmacology of this combination.

Reference: https://www.pharmacyregulation.org/registration-assessment#stage-8-order-31