Xylocard (Lidocaine) Infusion Dosing for Ventricular Arrhythmias
For treating ventricular arrhythmias, the recommended Xylocard (lidocaine) infusion dosing regimen is an initial bolus of 1 mg/kg (maximum 100 mg), followed by a maintenance infusion of 20-50 μg/kg/min (1.4-3.5 mg/min in a 70 kg patient). 1
Initial Bolus Administration
- Begin with an intravenous bolus of 1 mg/kg (not exceeding 100 mg) to rapidly achieve therapeutic blood levels 1
- Additional bolus injections of 0.5 mg/kg can be administered every 8-10 minutes if necessary, up to a maximum total loading dose of 4 mg/kg 1
- For ventricular fibrillation during cardiac arrest, use a 100 mg bolus that may be repeated after 5-10 minutes 1
Maintenance Infusion
- After the initial bolus, start a continuous infusion at 20-50 μg/kg/min (1.4-3.5 mg/min for a 70 kg patient) 1
- Higher maintenance doses (40-50 μg/kg/min) may be required for patients who needed more than one bolus dose to suppress arrhythmias 1
- Therapeutic blood levels are typically up to 5 μg/ml 1
Dosage Adjustments
- A second bolus injection of 0.5 mg/kg may be needed 30-120 minutes after initiation of therapy due to transient subtherapeutic plasma concentrations, without changing the maintenance infusion rate 1
- If arrhythmias recur after 8-10 hours of stable infusion, administer another 0.5 mg/kg bolus and increase the maintenance infusion rate 1
- Reduce the infusion rate by 1 mg/min after 12-24 hours of therapy, or monitor blood levels, as lidocaine half-life increases over time 1
Special Populations Requiring Dose Reduction
- Elderly patients (>70 years) 1
- Patients with congestive heart failure (half-life >20 hours) 1
- Patients with cardiogenic shock (even longer half-life) 1
- Patients with hepatic dysfunction (lidocaine is eliminated almost exclusively by the liver) 1
- Patients with severe renal dysfunction 1
- Patients with preexisting neurologic dysfunction 1
Duration of Therapy
- For prophylactic use, discontinue therapy after the first 12-24 hours unless other therapeutic indications are present 1
- For treatment of ventricular arrhythmias, infusions may be continued for 6-24 hours, after which the need for further arrhythmia management should be reassessed 1
Monitoring for Toxicity
- Perform frequent clinical assessments for signs of toxicity 1
- Central nervous system symptoms: nausea, drowsiness, perioral numbness, dizziness, confusion, slurred speech, muscle twitching, respiratory depression, double vision, tremor, altered consciousness 1
- Cardiovascular effects: bradycardia, sinus arrest, hypotension 1
- Consider measuring serum levels with prolonged or high infusion rates or if neurologic condition changes 1
Clinical Indications for Lidocaine Use
- Ventricular premature beats that are frequent (>6/min), closely coupled (R on T), multiform, or occurring in short bursts of three or more in succession 1
- Ventricular tachycardia and ventricular fibrillation resistant to defibrillation 1
- For sustained monomorphic ventricular tachycardia not associated with angina, pulmonary edema, or hypotension 1
Contraindications
- Complete heart block 1
- Wide complex tachycardia attributable to accessory conduction pathways 1
- Proven allergic or hypersensitivity reactions to lidocaine 1
Important Considerations
- Lidocaine has been shown to be less effective than amiodarone for ventricular arrhythmias in recent data 1
- High concentrations may cause myocardial depression, hypotension, and seizures 1
- Increasing the maintenance infusion rate without an additional bolus results in very slow increases in plasma concentration (>6 hours to reach new plateau) 1
- Bolus therapy should be the only administration method during cardiac arrest, given every 2-3 minutes as needed 1