After three shocks have been delivered, which antiarrhythmic is recommended first?

After three shocks have been delivered, which antiarrhythmic is recommended first?

• A. Lidocaine 1 mg/kg IV/IO
• B. Amiodarone 300 mg IV/IO bolus
• C. Magnesium sulfate 2 g IV
• D. Epinephrine 1 mg IV/IO

Answer: (B)

When a shockable rhythm has required several defibrillations, the goal is to suppress recurrent ventricular arrhythmias and improve the chance of ROSC by adding an antiarrhythmic. Amiodarone is the preferred first-line antiarrhythmic for VF/pVT in this setting because it broadens the refractory period and stabilizes cardiac rhythms, helping prevent further episodes after defibrillation. The recommended dose is a 300 mg IV/IO bolus, with a second dose of 150 mg IV/IO if VT/VF persists. Lidocaine can be an alternative if amiodarone isn’t available, but amiodarone has better outcomes in this scenario. Magnesium sulfate is reserved for torsades de pointes or suspected Mg deficiency, not routine VF/pVT. Epinephrine is important for perfusion during CPR but is not an antiarrhythmic, so it doesn’t replace the need for an antiarrhythmic after multiple shocks.

When a shockable rhythm has required several defibrillations, the goal is to suppress recurrent ventricular arrhythmias and improve the chance of ROSC by adding an antiarrhythmic. Amiodarone is the preferred first-line antiarrhythmic for VF/pVT in this setting because it broadens the refractory period and stabilizes cardiac rhythms, helping prevent further episodes after defibrillation. The recommended dose is a 300 mg IV/IO bolus, with a second dose of 150 mg IV/IO if VT/VF persists. Lidocaine can be an alternative if amiodarone isn’t available, but amiodarone has better outcomes in this scenario. Magnesium sulfate is reserved for torsades de pointes or suspected Mg deficiency, not routine VF/pVT. Epinephrine is important for perfusion during CPR but is not an antiarrhythmic, so it doesn’t replace the need for an antiarrhythmic after multiple shocks.