What is the maximum recommended dose of flecainide?

Maximum Recommended Dose of Flecainide

The maximum recommended dose of flecainide is 300 mg/day (150 mg every 12 hours) for patients with paroxysmal supraventricular arrhythmias, and 400 mg/day for patients with sustained ventricular tachycardia. 1

Dosing Guidelines by Indication

For Paroxysmal Supraventricular Tachycardia (PSVT) and Paroxysmal Atrial Fibrillation (PAF):

• Initial dose: 50 mg every 12 hours
• Dose increases: May increase in increments of 50 mg twice daily every four days until efficacy is achieved
• Maximum dose: 300 mg/day 1, 2

For Sustained Ventricular Tachycardia (VT):

• Initial dose: 100 mg every 12 hours
• Dose increases: May increase in increments of 50 mg twice daily every four days
• Maximum dose: 400 mg/day 1
• Note: Most patients with sustained VT do not require more than 300 mg/day 1

Special Population Considerations

Renal Impairment:

• For severe renal impairment (creatinine clearance ≤35 mL/min/1.73 m²): Initial dose should be 100 mg once daily (or 50 mg twice daily) 1
• For less severe renal disease: Initial dose should be 100 mg every 12 hours 1
• Frequent plasma level monitoring is required to guide dosage adjustments in these patients 1

Pediatric Dosing:

• Under six months of age: Initial dose approximately 50 mg/m² body surface area daily, divided into 2-3 doses 1
• Over six months of age: Initial dose may be increased to 100 mg/m² per day 1
• Maximum recommended dose: 200 mg/m² per day 1

Drug Interactions:

• When administered with amiodarone: Reduce flecainide dose by 50% 1, 3
• Monitor digoxin concentrations when co-administered with flecainide 2

Monitoring Parameters

ECG Monitoring:

• PR and QRS intervals should be monitored regularly 2
• Discontinue or reduce dose if QRS duration increases >25% from baseline 3
• QRS duration >200 ms is associated with higher mortality 3

Plasma Level Monitoring:

• Trough plasma levels should be maintained between 0.2-1.0 mcg/mL 1
• Levels above 0.7-1.0 mcg/mL require close monitoring 3, 2
• Plasma level monitoring is particularly important in patients with renal impairment, hepatic disease, heart failure, and those on concurrent amiodarone therapy 3

Important Precautions and Contraindications

Flecainide is contraindicated in patients with:

• Structural heart disease or coronary artery disease 3, 2
• Cardiogenic shock 2
• Sinus or AV conduction disease (without pacemaker) 2
• Brugada syndrome 2
• Atrial flutter (unless concomitant AV nodal therapy is used) 2

Adverse Effects to Monitor

• Atrial flutter with 1:1 AV conduction
• QT prolongation
• Torsades de pointes
• Worsening heart failure
• Bradycardia 2
• Visual disturbances, dizziness, and headaches 4

Flecainide has a long half-life (12-27 hours), and steady-state plasma levels may not be achieved until after 3-5 days of therapy at a given dose. Therefore, dosage increases should not be made more frequently than once every four days 1.