A 22-year-old woman presents with palpitations of sudden onset. ECG shows a regular narrow complex tachycardia at 190 per minute with no visible P waves. Vagal maneuvers fail. Which drug is most appropriate for immediate termination?
- A Digoxin intravenously
- B Amiodarone infusion over 1 hour
- C Adenosine by rapid intravenous push ✓
- D Sotalol orally
Correct answer: C. Adenosine by rapid intravenous push
Explanation
Adenosine given as a rapid bolus with a flush transiently blocks AV nodal conduction and terminates most atrioventricular nodal reentrant tachycardias within seconds. Its half life under 10 seconds makes side effects like flushing and chest tightness fleeting. Amiodarone works too slowly for acute termination of a stable narrow complex tachycardia, digoxin takes hours, and sotalol is an oral maintenance agent, not a terminating drug. Adenosine also serves a diagnostic role in revealing atrial activity.
Reference: Ganong's Review of Medical Physiology, 27th ed.
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