Sotalol: a new class III antiarrhythmic agent.

The chemistry, pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage of sotalol hydrochloride are reviewed. The chemical name of sotalol hydrochloride is 4'-[1-hydroxy-2-(isopropylamino)ethyl]methanesulfonanilide monohydrochloride. Sotalol is a class III antiarrhythmic that prolongs the action potential and refractoriness of cardiac tissue and has potent nonselective beta-blocking activity. Sotalol is well absorbed after oral administration. The pharmacokinetics of sotalol can be described by an open, linear, two-compartment model. The drug is eliminated primarily by the kidneys; mean elimination half-life is 12 hours. Sotalol has been found to be effective in controlling life-threatening ventricular arrhythmias, including sustained ventricular tachycardia, ventricular fibrillation, and premature ventricular complexes. Although sotalol has FDA-approved labeling for use in the treatment of ventricular arrhythmias only, it is also effective against a variety of supraventricular arrhythmias. Noncardiac adverse effects include fatigue, impotence, depression, headache, nausea, diarrhea, and increased triglyceride levels. Cardiovascular adverse effects include atrioventricular block, bradycardia, hypotension, exacerbation of heart failure, and polymorphic ventricular tachycardia. Overall, 11-21% of patients experience adverse effects; 6-18% of these patients have reactions serious enough to warrant the discontinuation of sotalol therapy. The initial dosage of oral sotalol hydrochloride in adults is 80 mg twice daily or 160 mg once daily; the dosage can be increased every three to four days in increments of 40-160 mg/day to a maximum of 480 mg/day. Sotalol is useful in the control of intractable, life-threatening ventricular arrhythmias, as well as a variety of supraventricular arrhythmias, in patients who do not respond to or are intolerant of more conventional antiarrhythmics.