Flecainide Uses, Dosage, Side Effects, Food Interaction and all others data.

Flecainide is a Class I anti-arrhythmic agent like encainide and propafenone. Flecainide’s development began in 1966 and was first synthesized in 1972 as an attempt to generate new anesthetics. It is used to prevent supraventricular and ventricular arrhythmias, as well as paroxysmal atrial fibrillation and flutter.

Flecainide was granted FDA approval on 31 October 1985.

Flecainide inhibits the action of sodium and potassium ion channels in the heart, raising the threshold for depolarization and correcting arrhythmias. Flecainide has a long duration of action, allowing for once daily dosing. The therapeutic index is narrow. Patients should not take this medication if there is already structural heart disease or left ventricular systolic dysfunction.

Trade Name Flecainide
Availability Prescription only
Generic Flecainide
Flecainide Other Names Flecaine, Flecainida, Flécaïnide, Flecainide, Flecainidum
Related Drugs metoprolol, propranolol, Xarelto, atenolol, diltiazem, digoxin, amiodarone, rivaroxaban, lidocaine, bisoprolol
Weight 100mg, 150mg, 50mg,
Type Oral tablet
Formula C17H20F6N2O3
Weight Average: 414.3427
Monoisotopic: 414.137811746
Protein binding

Flecainide is 40% bound to protein in serum, mainly to alpha-1-acid glycoprotein and minorly to serum albumin.

Groups Approved, Withdrawn
Therapeutic Class
Manufacturer Pharmachemie
Available Country United States, Netherlands
Last Updated: September 19, 2023 at 7:00 am


Flecainide is a class Ic antiarrhythmic agent used to manage atrial fibrillation and paroxysmal supraventricular tachycardias (PSVT).

In New Zealand and America, flecainide is indicated to prevent supraventricular arrhythmias and ventricular arrhythmias. In the United States, it is also indicated to prevent paroxysmal atrial fibrillation and flutter.

Flecainide is also used to associated treatment for these conditions: Atrial Fibrillation, Ventricular Tachycardia (VT), Severe Atrioventricular nodal reentrant tachycardia, Severe Paroxysmal atrial fibrillation, Severe Paroxysmal supraventricular tachycardia, Severe Supraventricular Tachycardias, Severe Sustained ventricular tachycardia, Severe ventricular arrhythmias

How Flecainide works

Flecainide blocks fast inward sodium channels and slowly unbinds during diastole, prolonging the refractory period of the heart. This blockade also shortens the duration of action potentials through the Purkinjie fibers. Flecainide also prevents delayed rectifier potassium channels from opening, lengthening the action potential through ventricular and atrial muscle fibers. Finally, flecainide also blocks ryanodine receptor opening, reducing calcium release from sarcoplasmic reticulum, which reduces depolarization of cells.


The oral LD50 in rats is 1346mg/kg and in mice is 170mg/kg. The subcutaneous LD50 in rats is 215mg/kg and in mice is 188mg/kg. The oral TDLO in women is 20mg/kg and in men is 40mg/kg/2W.

Patients experiencing an overdose may present with ECG abnormalities such as a lengthened PR interval, increased QRS duration, prolonged QT interval, increased amplitude of the T wave, reduced myocardial rate and contractility, hypotension, or death. Treat patients with symptomatic and supportive treatment which may involve administration of inotropic agents, assisted respiration, circulatory assistance, and acidification of the urine. Hemodialysis is not expected to be useful in the removal of flecainide from serum.

Food Interaction

  • Take with or without food. The absorption is unaffected by food.

Volume of Distribution

The average volume of distribution in 8 male subjects is 5.0-13.4L/kg.

Elimination Route

Oral flecainide has a Tmax of 3-4h and a bioavialability of 90%. Taking flecainide with food or aluminum hydroxide antacids do not significantly affect the absorption of flecainide.

Half Life

In healthy subjects, intravenous flecainide has an average half life of 13 hours for a single dose and 16 hours for multiple oral doses. In patients with a ventricular premature complex, flecainide has a half life of 20 hours. The half life of meta-O-dealkylated flecainide, a major metabolite of flecainide, is 12.6h.


The average clearance of intravenous flecainide is 4.6-12.1mL/min/kg in 8 male subjects. For oral flecainide, the clearance was 4-20mL/min/kg.

Elimination Route

Approximately 86% of a single oral dose is eliminated in the urine, with 42% as unchanged flecainide and 14% as meta-O-dealkylated flecainide, a similar amount of the meta-O-dealkylated lactam of flecainide, approximately 3% as an unidentified acid metabolite, and 6,12,13 5% is eliminated in the feces.

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