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Statin-warfarin interaction — GPhC CRA MCQ

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ModerateDrug InteractionsStatin-warfarin interactionGPhC CRA

A 70-year-old woman presents a prescription for atorvastatin 20 mg at night. She is currently taking amlodipine 10 mg, lisinopril 20 mg, and warfarin. Her INR has been stable at 2.5 for the past three months. What is the most appropriate action regarding this new prescription?

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Correct answer: D — Dispense the atorvastatin and advise her INR should be checked within a few days of starting

Statins can potentiate the effect of warfarin and increase the INR. When initiating a statin in a patient on warfarin, it is important to monitor the INR more frequently, ideally within a few days of starting the new medication. The prescription is clinically appropriate, but the patient should be advised that INR monitoring is needed. There is no reason to refuse dispensing or to switch statin at this stage.

Reference: BNF Drug Interactions; NICE CKS Anticoagulation