Class III antiarrhythmic agents like sotalol and amiodarone are effective for ventricular arrhythmias but have distinct, complex pharmacologic and side effect profiles that must be managed carefully.
Class III antiarrhythmic agents are characterized by their ability to prolong action potential and increase refractoriness. The use of these drugs namely, sotalol hydrochloride and amiodarone hydrochloride, is rising. Both agents are effective for treating a range of ventricular arrhythmias, and amiodarone in particular has been linked with improved mortality in certain patient populations compared with class I agents. Sotalol and amiodarone have individual, complex pharmacologic profiles. As a result, there are also differences in their side effects and proarrhythmic actions. Sotalol is associated with side effects related to beta-adrenergic blockade and an incidence of proarrhythmia similar to that of class Ia agents. Amiodarone is associated with pulmonary toxicity and other adverse events, but rarely induces torsades de pointes. These agents must be differentiated from pure class III potassium channel blockers, such as the dextro isomer form of sotalol, which is linked to increased mortality compared with placebo in post-myocardial infarction patients with reduced ventricular function or a history of heart failure.
Jerry L. Bauman (Tue,) studied this question.