Dexmedetomidine is used for procedural sedation in an adult during an awake fibreoptic intubation. Its mechanism of action and key property that distinguishes it from benzodiazepines and propofol is:

• A GABA-A receptor potentiation producing sedation without respiratory depression
• B NMDA receptor antagonism producing dissociative sedation
• C Selective alpha-2 adrenoreceptor agonism producing sedation, analgesia and anxiolysis with preserved ventilatory drive ✓
• D Opioid mu receptor partial agonism providing sedation and analgesia

Explanation

Dexmedetomidine is a highly selective alpha-2 adrenoreceptor agonist (alpha-2 : alpha-1 selectivity ratio 1620:1) that produces its sedative and analgesic effects primarily through locus coeruleus receptors, mimicking natural non-REM sleep. Its key distinguishing feature is preservation of respiratory drive and airway reflexes even at sedative doses, making it uniquely suitable for awake fibreoptic intubation, ICU sedation requiring neurological assessment, and procedures where respiratory depression is hazardous. Propofol and benzodiazepines act via GABA-A and cause dose-dependent respiratory depression.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.