Flecainide Dosing for Atrial Fibrillation

Initial Dosing Strategy

The American Heart Association and American College of Cardiology recommend starting flecainide at 50 mg every 12 hours and increasing by 50 mg twice daily every 4 days as needed, up to a maximum of 150 mg every 12 hours (300 mg/day total) for patients with atrial fibrillation 1, 2
Begin with 50 mg twice daily (100 mg/day total) for patients with paroxysmal atrial fibrillation or paroxysmal supraventricular tachycardia 1, 2

Increase in 50 mg twice daily increments every 4 days until efficacy is achieved for patients with atrial fibrillation 1, 2
The American Heart Association, American College of Cardiology, and Heart Rhythm Society specify a dosing range of 50-200 mg every 12 hours for maintenance therapy 1, 2
Maximum dose is 150 mg twice daily (300 mg/day total) for paroxysmal supraventricular arrhythmias including atrial fibrillation 1, 3, 4

Oral: 200-300 mg as a single dose for pharmacological cardioversion of acute atrial fibrillation 3, 5, 6
Intravenous: 1.5-3.0 mg/kg over 10-20 minutes for pharmacological cardioversion of acute atrial fibrillation 3, 5, 6
The "pill-in-the-pocket" approach (single oral dose for self-administration) is reasonable once safety has been demonstrated in a monitored setting for patients with atrial fibrillation 1, 2

Initiate therapy in-hospital for patients with sustained ventricular tachycardia, though outpatient initiation is acceptable for supraventricular arrhythmias in selected patients 3

Absolute contraindications include structural heart disease (coronary artery disease, heart failure, significant left ventricular dysfunction) for patients with atrial fibrillation 1, 2
Absolute contraindications include sinus or AV node dysfunction for patients with atrial fibrillation 1, 2
Absolute contraindications include Brugada syndrome for patients with atrial fibrillation 1, 2
Absolute contraindications include atrial flutter without concomitant AV nodal blocking therapy for patients with atrial fibrillation 1, 2

Never use flecainide in patients with structural heart disease - this is associated with increased mortality as demonstrated in the CAST trial 1, 2
Watch for atrial flutter with 1:1 AV conduction - this potentially life-threatening complication requires concomitant AV nodal blocking agents 3, 5, 6
Flecainide is metabolized by CYP2D6, which is genetically absent in 7-10% of the population and can be inhibited by quinidine, fluoxetine, and tricyclics - these interactions can dramatically increase plasma concentrations 1, 2

The American Heart Association recommends an initial dose of flecainide for supraventricular tachyarrhythmias of 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 7, 8

The American College of Cardiology recommends monitoring PR and QRS intervals during dose titration, and considers monitoring flecainide plasma levels, keeping trough levels below 0.7-1.0 mcg/mL 9, 10
Flecainide is contraindicated in patients with structural heart disease, sinus or AV conduction disease, cardiogenic shock, Brugada syndrome, and atrial flutter without concomitant AV nodal blocking therapy 7, 8

Potential adverse effects of flecainide include atrial flutter with 1:1 AV conduction, QT prolongation and torsades de pointes, worsening heart failure, and bradycardia 7, 8
The American Heart Association recommends monitoring closely with amiodarone, digoxin, ritonavir, saquinavir, and tipranavir, and using caution with other QT-prolonging drugs 7, 8