FLECAIN

What it is

FLECAIN contains flecainide acetate in 50 mg and 100 mg tablet strengths. The 50 mg tablets are white to off-white, circular, biconvex tablets debossed with F1, with an approximate diameter of 6.5 mm. The 100 mg tablets are white to off-white, circular, biconvex tablets debossed with F and 2 separated by a scoreline, with an approximate diameter of 8.8 mm. Flecainide acetate belongs to the membrane stabilising (Class 1) group of antiarrhythmic agents.

Approved indications —

Supraventricular arrhythmias due to pre-excitation syndromes such as Wolff-Parkinson-White and Lown-Ganong-Levine syndromes — Supraventricular arrhythmias due to dual atrioventricular nodal pathways in patients with debilitating symptoms — Paroxysmal atrial fibrillation or flutter associated with disabling symptoms — Life-threatening ventricular arrhythmias not controlled by other drugs Although flecainide acetate may be effective in supraventricular arrhythmias in patients with structural heart disease, its use has been associated with life-threatening and occasionally fatal ventricular arrhythmias. In these patients, particularly in the presence of impaired left ventricular function, flecainide acetate should be used with extreme caution, preferably after other antiarrhythmic drugs have been tried or considered inappropriate. Use of flecainide acetate in chronic atrial fibrillation has not been adequately studied and is not recommended.

Dosing overview

For patients with supraventricular arrhythmias, the recommended starting dose is 50 mg every 12 hours, with doses increased in increments of 50 mg twice daily every four days until efficacy is achieved. The maximum recommended dose for paroxysmal supraventricular arrhythmias is 300 mg daily. For sustained ventricular tachycardia, the recommended starting dose is 100 mg every 12 hours, which may be increased in increments of 50 mg twice daily every four days until efficacy is achieved. Most patients do not require more than 150 mg every 12 hours, and the maximum dose recommended is 400 mg daily. Flecainide has a long half-life of 12 to 27 hours in patients. Steady-state plasma levels may not be achieved until the patient has received 3 to 5 days of therapy at a given dose. Therefore, increases in dosage should be made no more frequently than once every four days.

Key safety warnings

In the Cardiac Arrhythmia Suppression Trial, oral flecainide was associated with a higher incidence of mortality or non-fatal cardiac arrest (19 out of 323 patients) as compared with placebo (7 out of 318 patients). An even higher incidence of mortality was observed in flecainide-treated patients with more than one myocardial infarction. The prophylactic use of Class I antiarrhythmic drugs following myocardial infarction should be considered potentially hazardous, and the use of these agents for other than life-threatening arrhythmias or severe symptoms due to arrhythmias is not recommended. Patients with structural heart disease treated with flecainide for supraventricular arrhythmias may be at increased risk for proarrhythmia and cardiac adverse events. The use of flecainide has been associated with life-threatening and occasionally fatal ventricular arrhythmias. In these patients, especially in the presence of impaired left ventricular function with ejection fraction of 40% or less, flecainide should be used with extreme caution, preferably after other antiarrhythmic drugs have been tried or considered inappropriate. A review of world literature revealed that ventricular tachycardia was experienced in 0.4% of 568 patients with paroxysmal atrial fibrillation or flutter treated with oral flecainide, while 10.5% of 19 patients in the literature with chronic atrial fibrillation experienced ventricular tachycardia or ventricular fibrillation. Flecainide acetate is not recommended for use in patients with chronic atrial fibrillation. Flecainide acetate has a mild negative inotropic effect and may cause or worsen congestive heart failure, particularly in patients with cardiomyopathy, pre-existing severe heart failure or ejection fractions of 40% or less. Flecainide acetate should be used cautiously in patients who are known to have a history of congestive heart failure or myocardial dysfunction. Flecainide acetate should not be used in patients with advanced sinus node disease and should be used only with extreme caution in patients with sick sinus syndrome because it may cause sinus bradycardia, sinus pause, or sinus arrest.

Contraindications

Flecainide acetate is contraindicated in: second or third degree atrioventricular block unless a pacemaker is present to sustain rhythm; right bundle branch block when associated with a left hemi-block unless a pacemaker is present to sustain rhythm; cardiogenic shock; asymptomatic premature ventricular contractions and/or asymptomatic non-sustained ventricular tachycardia in patients with a history of myocardial infarction; known hypersensitivity to the drug; and in patients with severe renal or hepatic impairment unless plasma level monitoring can be done.

Regulatory history

FLECAIN flecainide acetate 50 mg and 100 mg tablet formulations were first listed on the Australian Register of Therapeutic Goods on 19 June 2018.