Warnings
Mortality. TAMBOCOR was included in the National Heart Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a longterm, multicenter, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously. An excessive mortality or non-fatal cardiac arrest rate was seen in patients treated with TAMBOCOR compared with that seen in patients assigned to a carefully matched placebo-treated group. This rate was 16/315 (5.1%) for TAMBOCOR and 7/309 (2.3%) for the matched placebo. The average duration of treatment with TAMBOCOR in this study was ten months.
The applicability of the CAST results to other populations (e.g., those without recent myocardial infarction) is uncertain, but at present, it is prudent to consider the risks of Class IC agents (including TAMBOCOR), coupled with the lack of any evidence of improved survival, generally unacceptable in patients without life-threatening ventricular arrhythmias, even if the patients are experiencing unpleasant, but not life-threatening, symptoms or signs.
Ventricular Pro-arrhythmic Effects in Patients with Atrial Fibrillation/Flutter. A review of the world literature revealed reports of 568 patients treated with oral TAMBOCOR for paroxysmal atrial fibrillation/flutter (PAF). Ventricular tachycardia was experienced in 0.4% (2/568) of these patients. Of 19 patients in the literature with chronic atrial fibrillation (CAF), 10.5% (2) experienced VT or VF. FLECAINIDE IS NOT RECOMMENDED FOR USE IN PATIENTS WITH CHRONIC ATRIAL FIBRILLATION. Case reports of ventricular proarrhythmic effects in patients treated with TAMBOCOR for atrial fibrillation/flutter have included increased PVCs, VT, ventricular fibrillation (VF), and death.
As with other Class I agents, patients treated with TAMBOCOR for atrial flutter have been reported with 1:1 atrioventricular conduction due to slowing the atrial rate. A paradoxical increase in the ventricular rate also may occur in patients with atrial fibrillation who receive TAMBOCOR. Concomitant negative chronotropic therapy such as digoxin or beta-blockers may lower the risk of this complication.
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TAMBOCOR SUMMARY
TAMBOCOR™
(flecainide acetate)
TAMBOCORTM(flecainide acetate) is an antiarrhythmic drug available in tablets of 50, 100 or 150 mg for oral administration.
In patients without structural heart disease, TAMBOCOR is indicated for the prevention of
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paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism associated with disabling symptoms
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paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms
TAMBOCOR is also indicated for the prevention of
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documented ventricular arrhythmias, such as sustained ventricular tachycardia (sustained VT), that in the judgment of the physician are life-threatening.
Use of TAMBOCOR for the treatment of sustained VT, like other antiarrhythmics, should be initiated in the hospital. The use of TAMBOCOR is not recommended in patients with less severe ventricular arrhythmias even if the patients are symptomatic.
Because of the proarrhythmic effects of TAMBOCOR, its use should be reserved for patients in whom, in the opinion of the physician, the benefits of treatment outweigh the risks.
TAMBOCOR should not be used in patients with recent myocardial infarction. (See Boxed Warnings.)
Use of TAMBOCOR in chronic atrial fibrillation has not been adequately studied and is not recommended. (See Boxed Warnings.)
As is the case for other antiarrhythmic agents, there is no evidence from controlled trials that the use of TAMBOCOR favorably affects survival or the incidence of sudden death.
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