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Quick facts
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 886662
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
INDICATIONS AND USAGE In patients without structural heart disease, Flecainide Acetate Tablets USP are indicated for the prevention of: • paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism associated with disabling symptoms • paroxysmal atrial fibrillation/flutter (PAF) associated with disabling symptoms Flecainide Acetate Tablets USP are also indicated for the prevention of: • documented ventricular arrhythmias, such as sustained ventricular tachycardia ( sustained VT), that in the judgment of the physician are life-threatening. Use of Flecainide Acetate Tablets USP for the treatment of sustained VT, like other antiarrhythmics, should be initiated in the hospital. The use of Flecainide Acetate Tablets USP is not recommended in patients with less severe ventricular arrhythmias even if the patients are symptomatic. Because of the proarrhythmic effects of Flecainide Acetate Tablets USP, its use should be reserved for patients in whom, in the opinion of the physician, the benefits of treatment outweigh the risks. Flecainide Acetate Tablets USP should not be used in patients with recent myocardial infarction. (See Boxed WARNINGS ). Use of Flecainide Acetate Tablets USP 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 Flecainide Acetate Tablets USP favorably affects survival or the incidence of sudden death.
About this medicine
DESCRIPTION Flecainide acetate is an antiarrhythmic drug available in tablets of 50 mg, 100 mg, or 150 mg for oral administration. Flecainide acetate is benzamide, N-(2-piperidinylmethyl)-2,5-bis (2,2,2-trifluoroethoxy)- monoacetate. The structural formula is given below. Flecainide acetate is a white crystalline substance with a pK a of 9.3. It has an aqueous solubility of 48.4 mg/mL at 37°C. Flecainide Acetate Tablets USP also contain the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate, microcrystalline cellulose, pregelatinized starch and sodium stearyl fumarate. flecainide
Who should not take it
CONTRAINDICATIONS Flecainide acetate tablets are contraindicated in patients with pre-existing second- or third-degree AV block, or with right bundle branch block when associated with a left hemiblock (bifascicular block), unless a pacemaker is present to sustain the cardiac rhythm should complete heart block occur. Flecainide acetate tablets are also contraindicated in the presence of cardiogenic shock or known hypersensitivity to the drug.
Warnings
WARNINGS Mortality Flecainide acetate was included in the National Heart Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, 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 flecainide acetate compared with that seen in patients assigned to a carefully matched placebo-treated group. This rate was 16/315 (5.1%) for flecainide acetate and 7/309 (2.3%) for the matched placebo. The average duration of treatment with flecainide acetate 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 flecainide acetate), 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 flecainide acetate 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 flecainide acetate for atrial fibrillation/flutter have included increased PVCs, VT, ventricular fibrillation (VF), and death. As with other Class I agents, patients treated with flecainide acetate for atrial flutter have been reported with 1:1 atrioventricular conduction due to slowing the atrial rate. […]
Reported side effects
ADVERSE REACTIONS In post-myocardial infarction patients with asymptomatic PVCs and non-sustained ventricular tachycardia, flecainide acetate therapy was found to be associated with a 5.1% rate of death and non-fatal cardiac arrest, compared with a 2.3% rate in a matched placebo group. (See WARNINGS ). Adverse effects reported for flecainide acetate, described in detail in the WARNINGS section, were new or worsened arrhythmias which occurred in 1% of 108 patients with PSVT and in 7% of 117 patients with PAF; and new or exacerbated ventricular arrhythmias which occurred in 7% of 1330 patients with PVCs, non-sustained or sustained VT. In patients treated with flecainide for sustained VT, 80% (51/64) of proarrhythmic events occurred within 14 days of the onset of therapy. 198 patients with sustained VT experienced a 13% incidence of new or exacerbated ventricular arrhythmias when dosage was initiated at 200 mg/day with slow upward titration, and did not exceed 300 mg/day in most patients. In some patients, flecainide acetate treatment has been associated with episodes of unresuscitatable VT or ventricular fibrillation (cardiac arrest). (See WARNINGS ). New or worsened CHF occurred in 6.3% of 1046 patients with PVCs, non-sustained or sustained VT. Of 297 patients with sustained VT, 9.1% experienced new or worsened CHF. New or worsened CHF was reported in 0.4% of 225 patients with supraventricular arrhythmias. There have also been instances of second- (0.5%) or third-degree (0.4%) AV block. Patients have developed sinus bradycardia, sinus pause, or sinus arrest, about 1.2% altogether (See WARNINGS ). The frequency of most of these serious adverse events probably increases with higher trough plasma levels, especially when these trough levels exceed 1 mcg/mL. There have been rare reports of isolated elevations of serum alkaline phosphatase and isolated elevations of serum transaminase levels. These elevations have been asymptomatic and no cause and effect relationship with flecainide acetate has been established. […]
Interactions with other medicines
Drug Interactions Flecainide acetate has been administered to patients receiving digitalis preparations or beta-adrenergic blocking agents without adverse effects. During administration of multiple oral doses of flecainide acetate to healthy subjects stabilized on a maintenance dose of digoxin , a 13% to 19% increase in plasma digoxin levels occurred at six hours postdose. In a study involving healthy subjects receiving flecainide acetate and propranolol concurrently, plasma flecainide levels were increased about 20% and propranolol levels were increased about 30% compared to control values. In this formal interaction study, flecainide acetate and propranolol were each found to have negative inotropic effects; when the drugs were administered together, the effects were additive. The effects of concomitant administration of flecainide acetate and propranolol on the PR interval were less than additive. In flecainide acetate clinical trials, patients who were receiving beta blockers concurrently did not experience an increased incidence of side effects. Nevertheless, the possibility of additive negative inotropic effects of beta blockers and flecainide should be recognized. Flecainide is not extensively bound to plasma proteins. In vitro studies with several drugs which may be administered concomitantly showed that the extent of flecainide binding to human plasma proteins is either unchanged or only slightly less. Consequently, interactions with other drugs which are highly protein bound (e.g., anticoagulants ) would not be expected. Flecainide acetate has been used in a large number of patients receiving diuretics without apparent interaction. Limited data in patients receiving known enzyme inducers ( phenytoin , phenobarbital , carbamazepine ) indicate only a 30% increase in the rate of flecainide elimination. In healthy subjects receiving cimetidine (1 gm daily) for one week, plasma flecainide levels increased by about 30% and half-life increased by about 10%. When amiodarone is added to flecainide therapy, plasma flecainide levels may increase two-fold or more in some patients, if flecainide dosage is not reduced. (See DOSAGE AND ADMINISTRATION ). […]
If too much is taken
OVERDOSAGE No specific antidote has been identified for the treatment of flecainide acetate overdosage. Overdoses ranging up to 8000 mg have been survived, with peak plasma flecainide concentrations as high as 5.3 mcg/mL. Untoward effects in these cases included nausea and vomiting, convulsions, hypotension, bradycardia, syncope, extreme widening of the QRS complex, widening of the QT interval, widening of the PR interval, ventricular tachycardia, AV nodal block, asystole, bundle branch block, cardiac failure, and cardiac arrest. The spectrum of events observed in fatal cases was much the same as that seen in the non-fatal cases. Death has resulted following ingestion of as little as 1000 mg; concomitant overdose of other drugs and/or alcohol in many instances undoubtedly contributed to the fatal outcome. Treatment of overdosage should be supportive and may include the following: removal of unabsorbed drug from the gastrointestinal tract, administration of inotropic agents or cardiac stimulants such as dopamine, dobutamine or isoproterenol; mechanically assisted respiration; circulatory assists such as intra-aortic balloon pumping; and transvenous pacing in the event of conduction block. Because of the long plasma half-life of flecainide (12 to 27 hours in patients receiving usual doses), and the possibility of markedly non-linear elimination kinetics at very high doses, these supportive treatments may need to be continued for extended periods of time. Hemodialysis is not an effective means of removing flecainide from the body. Since flecainide elimination is much slower when urine is very alkaline (pH 8 or higher), theoretically, acidification of urine to promote drug excretion may be beneficial in overdose cases with very alkaline urine. There is no evidence that acidification from normal urinary pH increases excretion.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 30 November 2023. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.