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Depolarising blocker hyperkalaemia — FRCA Primary MCQ

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ModeratePharmacologyDepolarising blocker hyperkalaemiaFRCA Primary

A patient three weeks after major burns avoids a drug because of severe hyperkalaemia risk. Which drug is being avoided?

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

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Correct answer: C — Suxamethonium

Suxamethonium can cause dangerous potassium release after burns due to extrajunctional receptor upregulation. Noradrenaline is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Salbutamol is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Hydrocortisone is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Morphine is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA pharmacology, link the clinical effect to the receptor, distribution or elimination mechanism rather than memorising isolated facts.

Reference: Peck, Hill & Williams Pharmacology for Anaesthesia and Intensive Care; BNF; Primary FRCA textbooks