Second generation antidysrhythmic agents

Several new antidysrhythmic agents have been or are about to be approved for the prevention and/or treatment of life-threatening or symptomatic ventricular arrhythmias. Prior to use in clinical practice, however, their relative risk/benefit ratio must be assessed. Whereas relief of bothersome symptoms of ventricular dysrhythmias may improve the patient's return to a more active role in society, one must be aware, at the same time, that these antidysrhythmics have adverse effects of their own that may significantly limit their effectiveness. None of these new antidysrhythmic agents has been shown to prevent suddent cardiac death in controlled trials. At the present time, studies are being conducted to assess the efficacy of these agents in preventing sudden cardiac death. The new antidysrhythmic agents are highly effective in treating a wide variety of ventricular, and in some cases, supraventricular dysrhythmias. These agents are orally effective and, because of their unique pharmacokinetic profile, can often be prescribed less often per day than first generation antidysrhythmics. Side effects, for the most part, are predictable and involve the gastrointestinal and central nervous systems. In most cases, such side effects are reversible with dosage reduction. Upon treating a patient for a potentially lethal dysrhythmia, a Class IC agent such as encainide, flecainide, or propafenone, may be considered as the first-line therapy. Class IB agents, although less effective when used alone, show augmented antidysrhythmic efficacy with a reduction in side effects when administered concomitantly with a Class IA agent, such as quinidine or procainamide.(ABSTRACT TRUNCATED AT 250 WORDS)