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Ketamine NMDA antagonism — FRCA Primary MCQ

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EasyPharmacologyKetamine NMDA antagonismFRCA Primary

A 45-year-old woman receives ketamine for procedural anaesthesia after trauma. Blood pressure rises and heart rate increases, but salivation is troublesome. Which receptor action best explains its main hypnotic and analgesic effect?

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Correct answer: E — NMDA receptor antagonism

Ketamine produces dissociative anaesthesia mainly through NMDA receptor antagonism. GABA-A agonism is more relevant to propofol, volatile agents and benzodiazepines. Alpha-2 agonism describes dexmedetomidine and clonidine rather than ketamine. The pearl is that ketamine's indirect sympathomimetic effects can support blood pressure but may be undesirable in selected patients.

Reference: RCoA Primary FRCA Syllabus 2026; Peck, Hill & Williams Pharmacology for Anaesthesia