ENKAID was included in the National Heart Lung and Blood Institute’s Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multi-center, 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 nonfatal cardiac arrest rate was seen in patients treated with ENKAID compared with that seen in patients assigned to a carefully matched placebo-treated group. This rate was 40/415 (9.6%) for ENKAID and 15/416 (3.6%) for the matched placebo. The average duration of treatment with ENKAID 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 1c agents (including ENKAID), 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.
ENKAID® (encainide hydrochloride) is an antiarrhythmic drug supplied as 25 and 35 mg capsules for oral administration.
ENKAID is indicated for the treatment of documented ventricular arrhythmias such as sustained ventricular tachycardia that, in the judgement of the physician, are life-threatening. Because of the proarrhythmic effects of ENKAID, its use should be reserved for patients in whom, in the opinion of the physician, the benefits of treatment outweigh the risks. ENKAID should not be used in patients with less severe ventricular arrhythmias, even if the patients are symptomatic.
Treatment with ENKAID should be initiated in a hospital. Patients should also be hospitalized at the time of a dose increase to 200 mg per day or above (see DOSAGE AND ADMINISTRATION).
The effects of ENKAID in patients with supraventricular arrhythmias and patients with recent myocardial infarction (except as described in the WARNINGS section) have not been adequately studied.
As is the case for other antiarrhythmic agents, there is no evidence from controlled trials that the use of ENKAID favorably affects survival or the incidence of sudden death.
Published Studies Related to Enkaid (Encainide)
Interaction of ischaemia and encainide/flecainide treatment: a proposed mechanism for the increased mortality in CAST I. [1995.12]
OBJECTIVE--To determine whether an interaction between encainide or flecainide and intercurrent ischaemia could account for the observed increase in cardiac and sudden deaths in the study group in the Cardiac Arrhythmia Suppression Trial (CAST) I. DESIGN--CAST I was a randomised, double blind, placebo controlled study in which patients received the drug which suppressed at least 6 premature ventricular contractions per minute by 80% or episodes of non-sustained ventricular tachycardia by 90%...
Interaction of baseline characteristics with the hazard of encainide, flecainide, and moricizine therapy in patients with myocardial infarction. A possible explanation for increased mortality in the Cardiac Arrhythmia Suppression Trial (CAST). [1994.12]
CONCLUSIONS: Although active treatment in CAST-I was associated with greater mortality than placebo with respect to almost all baseline variables, the therapeutic hazard was more than expected in patients with non-Q-wave myocardial infarction and (for total mortality) frequent premature VPDs and higher heart rates, suggesting that the adverse effect of encainide or flecainide therapy is greater when ischemic and electrical instability are present. The relative hazard of therapy with moricizine in the sicker CAST-II population was greater in those using diuretics. Thus, although these drugs have the common ability to suppress ventricular ectopy after myocardial infarction, their detrimental effects on survival may be mediated by different mechanisms in different populations, emphasizing the complex, poorly understood hazards associated with antiarrhythmic drug treatment.
Circadian pattern of arrhythmic death in patients receiving encainide, flecainide or moricizine in the Cardiac Arrhythmia Suppression Trial (CAST). [1994.02]
OBJECTIVES. The purpose of this study was to assess the effect of antiarrhythmic drugs on the timing of arrhythmic death.Planning of future antiarrhythmic drug trials will need to take this information into account.
Mortality following ventricular arrhythmia suppression by encainide, flecainide, and moricizine after myocardial infarction. The original design concept of the Cardiac Arrhythmia Suppression Trial (CAST). [1993.11.24]
OBJECTIVE--To test the hypothesis that in survivors of myocardial infarction, the suppression of ventricular premature depolarizations improves survival free of cardiac arrest and arrhythmic death... Treatment strategies designed solely to suppress these arrhythmias should no longer be followed.
Impact of food on the bioavailability of encainide. [1992.09]
The bioavailability of drugs that undergo extensive presystemic hepatic metabolism may be increased by concomitant ingestion with food. The effect of food on the bioavailability of encainide, a class IC antiarrhythmic agent, was evaluated in 14 healthy subjects in this randomized crossover study...
Clinical Trials Related to Enkaid (Encainide)
Cardiac Arrhythmia Suppression Trial (CAST) [Completed]
To determine whether drug treatment of asymptomatic ventricular arrhythmias in
post-myocardial infarction patients reduced the incidence of sudden cardiac death and total
Cardiac Arrhythmia Pilot Study (CAPS) [Completed]
Page last updated: 2007-06-01