Question

Alternative drug for cardiac arrest in place of epinephrine is?

• A. Amiodarone infusion
• B. Atropine
• C. High dose vasopressin
• D. Adenosine

Hint:

Look for the only option that is a direct vasoconstrictor rather than an antiarrhythmic.

Answer 1

The Correct Option is C

Step 1: During cardiac arrest the primary goal of a pressor is to raise coronary and cerebral perfusion pressure by causing systemic vasoconstriction. Epinephrine does this through alpha-adrenergic receptors, and the resuscitation algorithm needs an agent that can substitute for it.
Step 2: Vasopressin (antidiuretic hormone) at high doses acts directly on smooth muscle V1 receptors, producing potent vasoconstriction that is independent of the adrenergic system. This makes it the recognised alternative vasopressor to epinephrine.
Step 3: Older American Heart Association (AHA) guidance noted that a single 40 unit dose of vasopressin may replace the first or second dose of epinephrine in pulseless arrest scenarios, including asystole and pulseless electrical activity, as well as ventricular fibrillation and pulseless ventricular tachycardia.
Step 4: The distractors are wrong because amiodarone is an antiarrhythmic for refractory shockable rhythms (not a pressor), atropine is used for symptomatic bradycardia, and adenosine is used for paroxysmal supraventricular tachycardia. Hence the answer is high dose vasopressin.