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Lithium and NSAID interaction — GPhC CRA MCQ

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HardDrug InteractionsLithium and NSAID interactionGPhC CRA

A 52-year-old man taking lithium carbonate MR 400mg twice daily asks for ibuprofen for a sprained ankle. He also takes ramipril and bendroflumethiazide. His last lithium level was at the upper end of the therapeutic range. What is the most important interaction to flag?

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Correct answer: B — Ibuprofen can increase lithium levels and toxicity risk

NSAIDs can reduce renal lithium clearance and increase lithium toxicity risk. ACE inhibitors and thiazide diuretics can also increase lithium levels, making this patient particularly high risk. OTC NSAID supply should be avoided or discussed with the prescriber, with alternative analgesia considered. The interaction would not be expected to lower lithium levels.

Reference: BNF