When is lidocaine used in ACLS, and what is its typical dosing?

• A. Lidocaine is not used in ACLS
• B. Lidocaine is used as the first-line antiarrhythmic; 100 mg IV
• C. Lidocaine is an ACLS alternative when amiodarone is unavailable or contraindicated; 1-1.5 mg/kg IV bolus, may repeat 0.5-0.75 mg/kg every 5-10 minutes up to 3 mg/kg total
• D. Lidocaine is used only for bradyarrhythmias; 2 mg/kg

Answer: (C)

Lidocaine in ACLS is a backup antiarrhythmic used for refractory ventricular fibrillation or pulseless ventricular tachycardia when amiodarone is unavailable or cannot be used. The recommended dosing is weight-based: an initial IV bolus of 1 to 1.5 mg/kg, followed by additional doses of 0.5 to 0.75 mg/kg every 5 to 10 minutes as needed, with a total maximum of 3 mg/kg. This reflects its role as an alternative rather than the first-line choice.

It’s not used for bradyarrhythmias, and it isn’t given as a fixed 100 mg dose or as the primary antiarrhythmic when amiodarone is available. The concept hinges on lidocaine’s place as a second-line option in the ACLS antiarrhythmic toolbox, used when amiodarone isn’t an option and the situation involves ventricular tachyarrhythmias during resuscitation.