Flecainide

Chemical Name N-(2-Piperidylmethyl)-2,5-bis(2,2,2-trifluoroethoxy)benzamide Common Name — 

After 2 hours the mixture is cooled to about 0°C and the crude product Is collected by filtration, washed with diethyl ether and dried in a vacuum oven. After treatment with decolorizing charcoal and recrystallization from an equivolume mixture of isopropanol and methanol, the product, 2,5-bis(2,2,2-trifluoroethoxy)-N-(2-piperidylmethyl)benzamide hydrochloride has a MP of 228°C to 229°C. 

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Fleca.inide, Elecainide acetate, a fluorobenzamide, is a derivative of procainamide, and has been reported to be efficacious in suppressing both supraventricular and ventricular arrhythmias (26—29). The dmg is generally reserved for patients with serious and life-threatening ventricular arrhythmias. Elecainide depresses phase 0 depolarization of the action potential, slows conduction throughout the heart, and significantly prolongs repolarization (30). The latter effect indicates flecainide may possess some Class III antiarrhythmic-type properties (31). 

Elecainide is weU absorbed and 90% of the po dose is bioavailable. Binding to plasma protein is only 40% and peak plasma concentrations are attained in about 1—6 h. Three to five days may be requited to attain steady-state plasma concentrations when multiple doses are used. Therapeutic plasma concentrations are 0.2—1.0 lg/mL. Elecainide has an elimination half-life of 12—27 h, allowing twice a day dosing. The plasma half-life is increased in patients with renal failure or low cardiac outputs. About 70% of the flecainide in plasma is metabolized by the Hver to two principal metaboUtes. The antiarrhythmic potency of the meta-O-dealkylated metaboUte and the meta-O-dealkylated lactam, relative to that of flecainide is 50 and 10%, respectively. The plasma concentrations of the two metaboUtes relative to that of flecainide are 3—25%. Elecainide is mainly excreted by the kidneys, 30% unchanged, the rest as metaboUtes or conjugates about 5% is excreted in the feces (1,2). 

I c With only little effect on action potential duration Lorcainide, Flecainide, Propafenone... 

Class IC antiarrhythmic drugs such as flecainide or propafenone block the Na+ channel (open state propafenone open and inactivated state) with a very long dissociation time constant so that they alter normal action potential propagation. Flecainide increased mortality of patients recovering from myocardial infarction due to its proarrhythmic effects (CAST study). Action potential is shortened in Purkinje fibres but is prolonged in the ventricles. 

Ventricular fibrillation should be terminated by electrical defibrillation. Alternatively, lidocaine can be injected intravenously. In cases with lower frequency, ventricular tachyarrhythmia class I diugs such as aj marine, flecainide or propafenone are more effective as a result of the use-dependence of lidocaine. For prophylaxis treatment, amiodarone or sotalol may be helpful or the implantation of a cardioverter-defibrillator system. Acute amiodarone (i.v. in higher doses) can also terminate ventricular tachyarrhythmias. This action, however, seems to be mediated by its INa-blocking side effects and not (or less) by its class III like effects. 

The Cardiac Arrhythmia Suppression Trial Investigators (1991) Mortality and morbidity in patients receiving encainide, flecainide or placebo. New Engl J Med 324 781... 

Flecainide (Tambocor) and propafenone (Rythmol) are examples of class I-C drags. These drugs have a direct stabilizing action on the myocardium, decreasing the height and rate of rise of cardiac action potentials, thus slowing conduction in all parts of the heart. 

ADMINISTERING FLECAINIDE AND PROPAFENONE. When administering flecainide, die nurse must carefully monitor die patient for cardiac arrhythmias. Therapeutic serum levels fall between 0.2 and 1 pg/mL. Life support equipment, including pacemaker, should be kept on stand-by during administration. 

Oral administration of bicarbonate may decrease the absorption of ketoconazole. Increased blood levels of quinidine, flecainide, or sympatiiomimetics may occur when these agents are administered with bicarbonate There is an increased risk of crystalluria when bicarbonate is administered with the fluoroquinolones. Fbssible decreased effects of lithium, methotrexate, chlorpropamide, salicylates, and tetracyclines may occur when these drag s are administered with sodium bicarbonate. Sodium bicarbonate is not administered within 2 hours of enteric-coated drugs the protective enteric coating may disintegrate before the drug reaches the intestine. 

Antiarrhythmics (e.g., disopyramide, flecainide, and others) P-Blockers (e.g., propranolol, metoprolol, atenolol, and others) Calcium channel blockers (e.g., verapamil and others)... 

Flecainide Dizziness, blurred vision, heart failure exacerbation... 

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