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Trimethoprim ACEI spironolactone — GPhC CRA MCQ

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ModerateInfectionsTrimethoprim ACEI spironolactoneGPhC CRA

A man taking ramipril and spironolactone is prescribed trimethoprim; potassium was recently 5.0 mmol/L. What is the most important interaction to flag?

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

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Correct answer: E — Trimethoprim can increase hyperkalaemia risk with ramipril and spironolactone

Trimethoprim can raise potassium and risk increases with ACE inhibitors and potassium-sparing diuretics. In this scenario, the pharmacist should prioritise safe supply, appropriate counselling and timely referral or clarification where needed. This is the single best answer because the other options would either delay assessment, ignore a clinically significant risk, or create an unsafe legal or professional outcome.

Reference: BNF