Which vasopressor is commonly used first-line to treat intraoperative hypotension due to vasodilation?

• A. Ephedrine
• B. Norepinephrine
• C. Phenylephrine
• D. Dopamine

Answer: (C)

When vessels dilate during surgery, blood pressure drops because systemic vascular resistance falls. The goal is to quickly restore tone with a vasopressor that constricts arteries without driving heart rate up. Phenylephrine fits this role as a pure alpha-1 agonist, providing rapid, titratable vasoconstriction that raises arterial pressure with minimal direct cardiac stimulation. It can cause a reflex reduction in heart rate, which is often acceptable or even helpful if tachycardia is present. Other options have drawbacks in this scenario: ephedrine increases BP partly by boosting heart rate and cardiac output, which can be undesirable if tachycardia is risky; norepinephrine is a potent vasoconstrictor with beta effects that can raise heart rate and myocardial demand; dopamine’s effects vary with dose and carry higher arrhythmia risk. So, phenylephrine is the best first-line choice for intraoperative hypotension due to vasodilation.