Encainide

Enca.inide, Encainide hydrochloride, a ben2amide derivative, is effective in the treatment of ventricular arrhythmias and refractory ventricular tachycardia (1,2). 

Encainide is almost completely absorbed from the GI tract. Eood may delay absorption without altering its bioavailabiUty. The dmg is rapidly metabolized in 90% of the patients to two principal metaboUtes, 0-demethylencainide (ODE) and 3-methoxy-O-demethylencainide (MODE), while the other 10% metabolize encainide slowly with Htde or no ODE or MODE formed. Encainide, ODE, and MODE are extensively protein bound 75—80% for encainide and ODE and 92% for MODE. Peak plasma concentrations are achieved in 30—90 min. Therapeutic plasma concentrations are very low the concentrations of ODE and MODE are approximately five times those of encainide. The findings with the metaboUtes are significant because ODE is 2—10 times and MODE, 1—4 times more effective than encainide as antiarrhythmics. The half-Hves for encainide in fast and slow metabolizers is 1—2 h and 6—12 h, respectively. The elimination half-life for ODE is 3—4 h and for MODE 6—12 h in fast metabolizers. Excretion occurs through the Hver and kidneys (1,2). 

Adverse effects of encainide therapy are dose-related. Diplopia and a bad taste in the mouth have been reported (1,2,25). 

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

Decreased cigarette consumption in smokers, easier to stop smoking Exaggerated response to warfarin and phenytoin Increased efficacy of omeprazole, increased toxicity of mephenytoin Absence of codeine efficacy, no effect of encainide, increased levels of tricyclic antidepressants, fluoxetine, phenothiazines Sustained paralysis to succinylcholine, possible increased toxicity of cocaine Unknown... 

Codeine, dextromethorphan, haloperidol, thioridazine, perphenazine, nortriptyline, desipramine, fluoxetine, norfluoxetine, TCAs (hydroxylation), beta-blockers such as timolol and metoprolol, type 1C antiarrhythmics encainide, flecainide TCAs (desmethylation), triazolam, alprazolam, midazolam, carbamazepine, terfenadine, quinidine, lidocaine, erythromycin, cyclosporin... 

Antiarrhythmics encainide, flecainide, mexiletine Beta-blockers alprenolol, metoprolol, propranolol, timolol Opiates codeine, dextromethorphan, ethylmorphine... 

Butoprozine Clofilium Phosphate Disobutamine Drobuli ne Encainide Emilium Tosylate Flecainide... 

Encainide Encainide, 4-methoxy-N-[2-[2-(l-methyl-2-piperidinyl)ethyl]phenyl]-benza-mide (18.1.15), is synthesized by acylating 2-(l-methyl-2-piperidylethyl)aniline with 4-methoxybenzoic acid chloride. The chemical structure of encainide is substantially different than other local anesthetics and antiarrhythmics [25-27]. 

Clinical use of encainide is primarily associated with the presence of serious ventricular tachycardia however, like flecainide, it is also sufficiently effective for atrial arrhythmia and is used for natural occurrences. A synonym of this drug is enkaid. 

C (flecainide, encainide, propafenone) - Marked depression of phase 0. Slight effect on repolarization. Profound slowing of conduction. Encainide was voluntarily withdrawn from the market, but is still available on a limited basis. 

MODE (3-methoxy-O-demethyl encainide) and ODE (0-demethyl encainide), metabolites more active than encainide on a per mg basis. 

Mortality In the National Heart, Lung, and Blood Institute s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic nonlife-threatening ventricular arrhythmias who had an Ml more than 6 days but less than 2 years previously, an excessive mortality or nonfatal cardiac arrest rate was seen in patients treated with encainide or flecainide (7.7%) compared with that seen in patients assigned to matched placebo-treated groups (3%). The averaged duration of treatment with encainide or flecainide in this study was 10 months. 

The average duration of treatment with encainide or flecainide in this study was 10 months. 

Mortality An excessive mortality or nonfatal cardiac arrest rate was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups. 

Inhibitors codeine, encainide, flecainide, fluoxetine, haloperidol, hydrocodone, 4-methoxy-amphetamine, metoprolol, mexiletine, oxycodone, paroxetine, propafenone, propoxyphene, risperidone, selegiline (deprenyl), thioridazine, most tricyclic antidepressants, timolol Fluoxetine, haloperidol, paroxetine, quinidine... 

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