Which is an advantage of using vasopressin?

• A. Acts independently of adrenergic receptors
• B. Requires intact adrenergic function to work
• C. Causes significant tachycardia
• D. Is effective only when catecholamines are effective

Answer: (A)

Vasopressin raises blood pressure by activating V1 receptors on vascular smooth muscle, producing vasoconstriction through a mechanism independent of the adrenergic system. This independence means it can restore vascular tone even when adrenergic receptors are desensitized or catecholamines are less effective, which is common in vasodilatory shock. Because of this, it’s a valuable adjunct that can reduce the required dose of catecholamines and help limit their dose-related side effects, such as tachycardia and increased myocardial oxygen demand. The other statements don’t reflect an advantage: it does not require intact adrenergic function to work, it is not known for causing significant tachycardia as its primary effect, and it can still be effective even when catecholamines are not fully effective.