What are the maximum doses of amiodarone (antiarrhythmic medication) infusion for ventricular (V) tachycardia and lidocaine (local anesthetic and antiarrhythmic medication) infusion?

Maximum Doses of Amiodarone and Lidocaine Infusions for Ventricular Tachycardia

For ventricular tachycardia, the maximum dose of amiodarone infusion is 2,100 mg/24 hours, and the maximum dose of lidocaine infusion is 4 mg/min (or 50 μg/kg/min). 1, 2

Amiodarone Infusion Protocol for V-Tach

Initial Loading and Maintenance

1. First 24 hours dosing (total ~1,000 mg):

   • Initial rapid infusion: 150 mg over 10 minutes
   • Early maintenance: 1 mg/min for 6 hours (360 mg)
   • Later maintenance: 0.5 mg/min for 18 hours (540 mg) 1, 3, 2

2. After first 24 hours:

   • Continue maintenance at 0.5 mg/min (720 mg/24 hours)
   • Use concentration of 1-6 mg/mL 2

3. For breakthrough episodes:

   • Supplemental boluses of 150 mg over 10 minutes
   • May be repeated for recurrent arrhythmias
   • Limited to 6-8 supplemental boluses in 24 hours 3, 2

Maximum Dose Considerations

• FDA label states that daily doses above 2,100 mg are associated with increased hypotension risk 2
• The rate of maintenance infusion may be increased to achieve effective arrhythmia suppression, but should not exceed this maximum 2
• Higher doses (1,050-2,100 mg/24h) have shown better efficacy than lower doses (525 mg/24h) in preventing recurrence of ventricular tachyarrhythmias 4, 5

Lidocaine Infusion Protocol for V-Tach

1. Loading dose:

   • Initial bolus: 1.0-1.5 mg/kg
   • Supplemental boluses: 0.5-0.75 mg/kg every 5-10 minutes as needed
   • Maximum total loading dose: 3 mg/kg 1

2. Maintenance infusion:

   • 2-4 mg/min (30-50 μg/kg/min) 1
   • This represents the maximum recommended infusion rate

Administration Considerations

Amiodarone

• Use a volumetric infusion pump for administration 3, 2
• Preferably administer through a central venous catheter 3, 2
• Use an in-line filter 3
• For infusions >1 hour, do not exceed concentrations of 2 mg/mL unless using a central line 2
• Infusions exceeding 2 hours must be administered in glass or polyolefin bottles containing D5W 2

Lidocaine

• Adjust dosing based on age, weight, hepatic and renal function 1
• Lower doses may be needed in elderly patients or those with liver dysfunction

Important Precautions

1. Amiodarone:

   • High-dose infusions faster than recommended can cause hepatocellular necrosis and acute renal failure 2
   • Monitor for hypotension (26% incidence), bradycardia, and AV block 6, 4
   • Concentrations >3 mg/mL in D5W are associated with high incidence of phlebitis 2

2. Lidocaine:

   • Monitor for CNS toxicity (confusion, seizures)
   • Watch for cardiovascular depression at high doses

Duration of Therapy

• Amiodarone maintenance infusion can be continued for 2-3 weeks regardless of age, renal function, or left ventricular function 2
• Limited experience with IV amiodarone beyond 3 weeks 2
• Infusions of antiarrhythmic drugs should generally be discontinued after 6-24 hours with reassessment of arrhythmia management needs 1

By following these dosing guidelines and monitoring for adverse effects, you can safely administer maximum doses of amiodarone and lidocaine for ventricular tachycardia while minimizing risks of toxicity.