Lidocaine Dosing for Ventricular Tachycardia

Initial Bolus Dosing

• The American College of Cardiology recommends giving 1 to 1.5 mg/kg IV bolus (not exceeding 100 mg) as the initial dose for ventricular tachycardia 1, 2
• Additional boluses of 0.5 to 0.75 mg/kg can be given every 5-10 minutes if the initial bolus is insufficient 1, 2
• The maximum total bolus dose should not exceed 3 to 4 mg/kg 2

Maintenance Infusion

• After successful bolus therapy, start a maintenance infusion at 1-4 mg/min (or 30-50 mcg/kg/min) 1
• The American College of Cardiology specifies a range of 20-50 mcg/kg/min (1.4-3.5 mg/min in a 70 kg patient) 3, 4

Dose Adjustments for Special Populations

• Reduce doses significantly in patients with heart failure, cardiogenic shock, or acute myocardial infarction, as lidocaine clearance is substantially decreased 2, 5
• In heart failure, lidocaine's half-life increases to >20 hours (compared to 1-2 hours normally), requiring appropriate dose reduction 5

Important Clinical Context

• Lidocaine is considered second-line therapy for monomorphic VT, as it is less effective than procainamide, sotalol, and amiodarone at terminating VT 1

When to Use Lidocaine

• Lidocaine remains appropriate as first-line therapy in the acute MI setting when treatment is indicated for VT or VF 2
• It is particularly useful for VT thought to be related to myocardial ischemia 3

When to Choose Alternative Agents

• For unstable VT with pulse, immediate synchronized DC cardioversion (100J, 200J, 360J) is the primary intervention, not pharmacologic therapy 3
• Amiodarone (150 mg IV over 10 minutes) is indicated for VT refractory to lidocaine 1, 3

Monitoring for Toxicity

• Watch for CNS symptoms: nausea, drowsiness, perioral numbness, dizziness, confusion, slurred speech, muscle twitching, seizures, and respiratory depression 4, 5
• Monitor for cardiovascular effects: bradycardia, sinus arrest, and hypotension 4, 5
• Lidocaine depresses myocardial contractility, requiring careful monitoring especially in hemodynamically compromised patients 3

Common Pitfalls to Avoid

• Do not use standard doses in patients with heart failure or shock without significant reduction—this is a critical error that can lead to toxicity 2, 5
• Do not rely on lidocaine as first-line therapy for stable VT in non-MI settings—procainamide or amiodarone are more effective 1