Salbutamol-induced hypokalaemia — MRCPCH TAS MCQ

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ModeratePharmacologySalbutamol-induced hypokalaemiaMRCPCH TAS

A 7-year-old receiving repeated nebulised bronchodilator for wheeze develops tremor, tachycardia and serum potassium of 2.9 mmol/L. Which drug is most likely responsible?

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Correct answer: C — Salbutamol

Salbutamol stimulates beta-2 receptors and drives potassium intracellularly through Na+/K+-ATPase activity, causing hypokalaemia. Ipratropium may cause dry mouth or blurred vision but is not the usual cause of this biochemical pattern. The teaching point is to monitor potassium when high-dose beta-agonists are used repeatedly.

Reference: BNFc; Nelson Textbook of Pediatrics; RCPCH Theory examination syllabi