Codeine CYP2D6 — FRCA Primary MCQ

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ModeratePharmacology - AnalgesicsCodeine CYP2D6FRCA Primary

Codeine requires CYP2D6 metabolism to which active compound?

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Correct answer: C — Morphine

Codeine is O-demethylated by CYP2D6 to morphine (~5-10% of dose). CYP2D6 polymorphisms significantly affect efficacy: poor metabolisers (~7% Caucasians) get minimal analgesia while ultra-rapid metabolisers may experience toxicity.

Reference: Peck Hill Williams 2014 Pharmacology for Anaesthesia and Intensive Care