Which drug is most likely to cause bradycardia when used for sedation in anesthesia?

Which drug is most likely to cause bradycardia when used for sedation in anesthesia?

• A. Dexmedetomidine
• B. Propofol
• C. Furosemide
• D. Hydromorphone

Answer: (A)

Bradycardia during sedation is most likely with drugs that diminish sympathetic activity and enhance vagal tone. Dexmedetomidine is a selective alpha-2 adrenergic agonist that markedly reduces sympathetic outflow, producing sedation and analgesia but also lowering heart rate and blood pressure. This bradycardia is a well-known and expected effect, especially with ongoing infusion. Propofol can also cause bradycardia due to vasodilation and myocardial depression, but its bradycardia is less characteristic than that seen with alpha-2 agonists. Furosemide is a diuretic and does not provide sedation; any bradycardia would be due to electrolyte disturbances rather than a direct sedative effect. Hydromorphone, while it can cause vagal-induced bradycardia as an opioid, is primarily an analgesic, and its bradycardia is less predictable in the context of sedation alone. Therefore, the drug most likely to cause bradycardia when used for sedation in anesthesia is dexmedetomidine.

Bradycardia during sedation is most likely with drugs that diminish sympathetic activity and enhance vagal tone. Dexmedetomidine is a selective alpha-2 adrenergic agonist that markedly reduces sympathetic outflow, producing sedation and analgesia but also lowering heart rate and blood pressure. This bradycardia is a well-known and expected effect, especially with ongoing infusion.

Propofol can also cause bradycardia due to vasodilation and myocardial depression, but its bradycardia is less characteristic than that seen with alpha-2 agonists. Furosemide is a diuretic and does not provide sedation; any bradycardia would be due to electrolyte disturbances rather than a direct sedative effect. Hydromorphone, while it can cause vagal-induced bradycardia as an opioid, is primarily an analgesic, and its bradycardia is less predictable in the context of sedation alone.

Therefore, the drug most likely to cause bradycardia when used for sedation in anesthesia is dexmedetomidine.