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Lithium and NSAIDs — GPhC CRA MCQ

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HardDrug InteractionsLithium and NSAIDsGPhC CRA

A 55-year-old man stabilised on lithium carbonate modified-release tablets asks to buy naproxen for acute back pain. His last lithium level was 0.8mmol/L and eGFR was 58mL/min/1.73m2. He takes ramipril for hypertension. What is the most important interaction to flag?

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Correct answer: C — naproxen can increase lithium concentrations and toxicity risk

NSAIDs can reduce renal lithium clearance and increase lithium concentrations. The risk is higher in a patient with reduced renal function and concurrent ACE inhibitor treatment. Symptoms of lithium toxicity include tremor, ataxia, diarrhoea and confusion. The pharmacist should avoid OTC naproxen supply and advise medical review for safer analgesia.

Reference: BNF