A 62-year-old man receives pancuronium 0.08 mg/kg for intubation. Five minutes later his heart rate rises from 72 to 118 beats per minute. The most likely mechanism of this tachycardia is:
- A Vagolytic action with associated catecholamine release ✓
- B Ganglionic blockade with unopposed parasympathetic outflow
- C Histamine release causing reflex sympathetic stimulation
- D Direct stimulation of cardiac beta-1 receptors
Correct answer: A. Vagolytic action with associated catecholamine release
Explanation
Pancuronium blocks muscarinic cardiac receptors (vagolysis at the sinoatrial node) and also inhibits neuronal catecholamine reuptake, increasing circulating noradrenaline, both producing tachycardia. Histamine release causes hypotension and bronchospasm and is typical of atracurium and mivacurium, not pancuronium. Vecuronium was developed specifically to remove this cardiovascular liability.
Reference: Miller's Anesthesia, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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