What is the maximum dose of lidocaine (antiarrhythmic medication) for treating ventricular tachycardia (VT) storm?

Maximum Lidocaine Dosing for Ventricular Tachycardia Storm

For treating ventricular tachycardia storm, the maximum lidocaine infusion rate is 4 mg/min (50 μg/kg/min) following a total loading dose of up to 3 mg/kg. 1

Initial Loading Dose Protocol

1. Initial bolus: 1-1.5 mg/kg IV (not to exceed 100 mg per dose) 1
2. Supplemental boluses: 0.5-0.75 mg/kg every 5-10 minutes as needed 1
3. Maximum total loading dose: 3 mg/kg 1

Maintenance Infusion Protocol

• Standard infusion rate: 2-4 mg/min (30-50 μg/kg/min) 1
• Duration: Continue infusion for at least 24 hours after successful conversion 1
• Dose adjustment: Reduce infusion rate after 12-24 hours due to increasing half-life 1

Dosing Considerations

Dose Reduction Required For:

• Elderly patients 1
• Patients with heart failure 1
• Patients with hepatic dysfunction 1
• Patients in cardiogenic shock 1

Monitoring Parameters:

• Clinical response (suppression of VT)
• Signs of lidocaine toxicity:
  • CNS: Perioral numbness, dizziness, confusion, slurred speech, seizures 1
  • Cardiovascular: Myocardial depression, hypotension 1

Alternative Therapies if Lidocaine Fails

If VT is refractory to maximum lidocaine dosing, consider:

1. Amiodarone: More effective than lidocaine for shock-resistant VT 2

   • Loading: 150 mg IV over 10 minutes
   • Followed by: 1 mg/min for 6 hours, then 0.5 mg/min

2. Procainamide: Superior to lidocaine in terminating monomorphic VT 3

   • 20-30 mg/min loading infusion up to 12-17 mg/kg
   • Maintenance: 1-4 mg/min

3. Magnesium: Particularly for VT associated with acute MI 1

   • 8 mmol bolus followed by 2.5 mmol/h infusion

Important Clinical Pearls

• Lidocaine is less effective for chronic ventricular arrhythmias compared to acute-onset arrhythmias 4
• Electrical cardioversion remains the primary intervention for hemodynamically unstable VT 5
• The effectiveness of lidocaine diminishes with prolonged VT, with amiodarone showing superior efficacy for incessant VT 2
• Lidocaine's half-life increases after 24-48 hours of administration, necessitating dose reduction 1

Pitfalls to Avoid

• Don't exceed the maximum total loading dose of 3 mg/kg, as higher doses significantly increase toxicity risk 1
• Don't maintain high infusion rates beyond 24 hours without dose adjustment, as lidocaine accumulates with prolonged administration 1
• Don't use lidocaine for wide complex tachycardia attributable to accessory conduction pathways 1
• Don't rely solely on lidocaine for incessant VT, as it has a 91% failure rate compared to 33% for amiodarone 2