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Dexmedetomidine alpha-2 pharmacology — FRCA Primary MCQ

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ModeratePharmacologyDexmedetomidine alpha-2 pharmacologyFRCA Primary

A 44-year-old woman receives dexmedetomidine sedation for awake fibreoptic intubation. She remains rousable, has a lower heart rate and requires less opioid. Which receptor action best explains these effects?

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Correct answer: B — Beta-2 adrenoceptor agonism

Dexmedetomidine is an alpha-2 adrenoceptor agonist producing sedation, sympatholysis and analgesic-sparing effects with relatively limited respiratory depression. It is not a GABA-A agonist like propofol or benzodiazepines. NMDA antagonism describes ketamine. The pearl is that bradycardia and hypotension are predictable dose-related adverse effects.

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