Which drug is a potent vasoconstrictor that should be administered during CPR?

• A. Epinephrine
• B. Atropine
• C. Vasopressin
• D. Dopamine

Answer: (C)

During CPR, lifting coronary and cerebral perfusion pressure is essential to improve chances of return of spontaneous circulation. A drug that produces strong vasoconstriction raises systemic vascular resistance, which increases the diastolic aortic pressure during chest compressions and boosts blood flow to the heart and brain.

Vasopressin works by activating V1 receptors on vascular smooth muscle, causing potent peripheral vasoconstriction. This makes it especially effective at raising perfusion pressures during resuscitation, helping to sustain blood flow to vital organs when the heart isn’t pumping effectively.

Other drugs have different roles. Atropine has no vasoconstrictive effect and isn’t a primary CPR vasopressor. Dopamine can raise blood pressure but is less potent as a vasoconstrictor in this setting and has more variable effects on perfusion. Epinephrine also increases perfusion pressure via alpha-adrenergic vasoconstriction, but vasopressin offers a different mechanism of achieving that constriction and, in some protocols, has been used as an alternative vasopressor during CPR.

So, the potent vasoconstrictor used during CPR is vasopressin.