FLECATAB

What it is

FLECATAB contains flecainide acetate in 50 mg and 100 mg tablet strengths. Flecainide acetate belongs to the membrane stabilising (Class 1) group of antiarrhythmic agents. The predominant action of flecainide acetate is to inhibit the fast, or sodium, channel which is largely responsible for the rapid upstroke of the myocardial action potential in cardiac conducting tissue.

Approved indications

— Supraventricular arrhythmias due to pre-excitation syndromes, such as Wolff-Parkinson-White and Lown-Ganong-Levine syndromes. — Supraventricular arrhythmias due to dual AV nodal pathways in patients with debilitating symptoms. — Paroxysmal atrial fibrillation/flutter associated with disabling symptoms. — Life threatening ventricular arrhythmias not controlled by other drugs, for continuous maintenance of normal rhythm following initial oral or intravenous therapy or conversion by other means.

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, with a maximum recommended dose of 300 mg per day. For sustained ventricular tachycardia, the recommended starting dose is 100 mg every 12 hours, with increases in increments of 50 mg twice daily every four days, where most patients do not require more than 150 mg every 12 hours, and the maximum dose recommended is 400 mg per day. Steady-state plasma levels in patients with normal renal and hepatic function 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 in patients with asymptomatic non-life threatening ventricular arrhythmias who had prior myocardial infarction, with an even higher incidence observed in patients with more than one myocardial infarction. Patients with structural heart disease treated with flecainide for supraventricular arrhythmias may be at increased risk for proarrhythmia and cardiac adverse events, with use associated with life-threatening and occasionally fatal ventricular arrhythmias, particularly in the presence of impaired left ventricular function with ejection fraction of 40% or less. Use of flecainide in chronic atrial fibrillation has not been adequately studied and is not recommended. Patients treated with flecainide for atrial flutter have been reported with 1:1 atrioventricular conduction due to slowing of the atrial rate, and a paradoxical increase in the ventricular rate may occur in patients with atrial fibrillation, although concomitant negative chronotropic therapy such as digoxin or beta-blockers may lower the risk of this complication. Because flecainide has a mild negative inotropic effect, it may cause or worsen congestive heart failure, particularly in patients with cardiomyopathy, pre-existing severe heart failure or ejection fractions of 40% or less, and should be used cautiously in patients with a history of congestive heart failure or myocardial dysfunction. Flecainide slows cardiac conduction sufficiently in most patients to produce measurable increases in the duration of the PR, QRS and QT intervals, with increases of more than 25% in the PR interval occurring commonly and approximately one third of patients developing first-degree heart block, whilst widening of the QRS of 25% or more is common.

Contraindications

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

Regulatory history

FLECATAB 100 mg tablets (ARTG 68651) were first listed on 26 August 1999, and FLECATAB 50 mg tablets (ARTG 344750) were first listed on 1 September 2021.