For stable SVT in a child, which medication and dosing sequence is recommended?

• A. Adenosine, first dose 0.1 mg/kg (max 6 mg); second dose 0.2 mg/kg (max 12 mg)
• B. Adenosine, first dose 0.2 mg/kg; second dose 0.4 mg/kg
• C. Amiodarone, 5 mg/kg
• D. Lidocaine, 1 mg/kg

Answer: (A)

Adenosine is the best choice for a child with stable SVT because it briefly blocks AV node conduction and often terminates the tachycardia, providing both therapeutic and diagnostic benefit with a very short duration of action. The recommended dosing is a rapid IV bolus of 0.1 mg/kg, maximum 6 mg. If the rhythm persists, give a second dose of 0.2 mg/kg, maximum 12 mg. Because adenosine is so fast-acting, it must be given as a rapid push followed by a saline flush to reach the heart quickly.

If adenosine fails to terminate the SVT or if the child becomes unstable, other interventions, such as synchronized cardioversion, are considered. Amiodarone and lidocaine are generally not first-line for stable SVT in children; they are used for other tachyarrhythmias (amiodarone for certain pulseless or VT/other refractory tachycardias, lidocaine mainly for ventricular arrhythmias).