What is the recommended dose of flecainide (anti-arrhythmic medication)?

Flecainide Dosing Recommendations

The recommended initial dose of flecainide for supraventricular tachyarrhythmias is 50 mg every 12 hours, which can be gradually increased to a maximum of 150 mg every 12 hours (300 mg/day) based on efficacy and tolerability. 1, 2

Dosing Algorithm

Initial Dosing

• Start with 50 mg every 12 hours for patients with paroxysmal supraventricular tachycardia (PSVT) or paroxysmal atrial fibrillation (PAF) 2
• For sustained ventricular tachycardia (VT), start with 100 mg every 12 hours (initiate in-hospital with rhythm monitoring) 2

Dose Titration

• Increase dose in increments of 50 mg twice daily every four days until efficacy is achieved 2
• Most patients respond to 100-200 mg twice daily 3, 4
• Maximum recommended dose for supraventricular arrhythmias is 300 mg/day 2
• For sustained VT, maximum recommended dose is 400 mg/day 2

Special Populations

• Renal impairment: For severe renal impairment (creatinine clearance ≤35 mL/min/1.73m²), start with 100 mg once daily (or 50 mg twice daily) 2
• Children: Initial dose approximately 50 mg/m² body surface area daily (divided into 2-3 doses) for children under 6 months; may increase to 100 mg/m² for children over 6 months 2
• When co-administered with amiodarone: Reduce usual flecainide dose by 50% 2

Monitoring

• Monitor PR and QRS intervals during dose titration 1
• Consider monitoring flecainide plasma levels, keeping trough levels below 0.7-1.0 mcg/mL 1
• Therapeutic plasma levels typically range between 0.2-1.0 mcg/mL 2
• Allow 3-5 days to achieve steady-state plasma levels before further dose adjustments 2

Precautions and Contraindications

• Avoid in patients with:
  • Structural heart disease (including ischemic heart disease) 1
  • Sinus or AV conduction disease (unless pacemaker present) 1
  • Cardiogenic shock 1
  • Brugada syndrome 1
  • Atrial flutter without concomitant AV nodal blocking therapy 1

Potential Adverse Effects

• Atrial flutter with 1:1 AV conduction 1
• QT prolongation and torsades de pointes 1
• Worsening heart failure 1
• Bradycardia 1
• Common non-cardiac side effects: dizziness, visual disturbances, headache 3, 5

Drug Interactions

• Monitor closely with amiodarone, digoxin, ritonavir, saquinavir, and tipranavir 1
• Reduce dose by 50% when administered with amiodarone 2
• Use caution with other QT-prolonging drugs 1

Efficacy Considerations

• Dose-response relationship has been demonstrated, with higher doses providing greater efficacy 4
• At 150 mg twice daily, 86% of PSVT patients and 61% of PAF patients achieved complete suppression of arrhythmia in clinical trials 4
• Long-term efficacy has been demonstrated with maintenance therapy 5