A 9-year-old experiences severe hypertension after an unmeasured bolus of phenylephrine. Which is the most appropriate treatment?

A 9-year-old experiences severe hypertension after an unmeasured bolus of phenylephrine. Which is the most appropriate treatment?

• A. Administer verapamil
• B. Administer esmolol
• C. Administer labetalol
• D. Administer phentolamine

Answer: (D)

Phenylephrine causes severe hypertension by overstimulating alpha-1 receptors, leading to intense vasoconstriction. The quickest way to counteract this is to block those receptors directly, which is precisely what an alpha-adrenergic antagonist does. Phentolamine blocks both alpha-1 and alpha-2 receptors, so it reverses the vasoconstriction and brings blood pressure down rapidly. It acts as an immediate antidote to phenylephrine overdose. Verapamil might lower blood pressure, but it doesn’t address the underlying receptor-driven vasoconstriction and can cause heart block or bradycardia. Esmolol blocks beta receptors, which can leave alpha-adrenergic effects unopposed and may worsen hypertension. Labetalol blocks both alpha and beta receptors but is not as direct or rapid an antidote for acute phenylephrine overdose as phentolamine.

Phenylephrine causes severe hypertension by overstimulating alpha-1 receptors, leading to intense vasoconstriction. The quickest way to counteract this is to block those receptors directly, which is precisely what an alpha-adrenergic antagonist does. Phentolamine blocks both alpha-1 and alpha-2 receptors, so it reverses the vasoconstriction and brings blood pressure down rapidly. It acts as an immediate antidote to phenylephrine overdose.

Verapamil might lower blood pressure, but it doesn’t address the underlying receptor-driven vasoconstriction and can cause heart block or bradycardia. Esmolol blocks beta receptors, which can leave alpha-adrenergic effects unopposed and may worsen hypertension. Labetalol blocks both alpha and beta receptors but is not as direct or rapid an antidote for acute phenylephrine overdose as phentolamine.