Which medication should be administered for hypotension caused by vasodilation during anesthesia?

The most appropriate medication for managing hypotension caused by vasodilation during anesthesia is phenylephrine. This medication is a selective alpha-1 adrenergic agonist that leads to vasoconstriction, which effectively raises blood pressure. When vasodilation occurs during anesthesia, it can result in decreased vascular resistance and lower blood pressure; therefore, the administration of a vasopressor like phenylephrine counteracts this effect by narrowing blood vessels, helping to restore hemodynamic stability.

In contrast, dobutamine primarily acts on beta-1 adrenergic receptors to increase cardiac contractility and heart rate, making it more suitable for managing heart failure or situations where cardiac output is compromised rather than directly addressing hypotension from vasodilation. Disopyramide is an antiarrhythmic that does not have significant effects on blood pressure in the context of anesthesia-related hypotension. Ephedrine, while it can increase blood pressure, primarily works through both alpha and beta adrenergic pathways and is often used for other types of hypotension, such as that due to bradycardia or reduced cardiac output rather than primarily from vasodilation.

Thus, the effectiveness of phenylephrine in specifically addressing the mechanism of hypotension due to