Sotalol antiarrhythmic activity

Sotalol, as the racemate (a 1 1 mixture of the d- and 1-enantiomers), has a well-documented class Ill-antiarrhythmic activity, without showing the various side-effects of amiodarone. The -adrenoceptor blockade by this agent, however, limits its use in patients with heart failure. Dofetilide is an example of a newer, rather pure class in-antiarrhythmic, virtually devoid of other pharmacological properties. 

The history of dmg discovery aptly illustrates the important role played in this process by serendipity. Clinical investigations on sotalol revealed that the agent had pronounced activity as an antiarrhythmic agent, an action that could be, and was, logically attributed to the compound s (3-blocking action. The observation that both enantiomers seemed to have equal potency, however, cast some doubt on this explanation for the antiarrhythmic activity. Subsequent work, perhaps spurred by this discrepancy, had in fact shown that sulfonanilides, which lack the... 

SOtalOl [ban, INN] (sotalol hydrochloride [usan] Sotacor ) is a (both class II and III) antiarrhythmic and (subtype-non-selective) -adrenoceptor antagonist, which is relatively water-soluble. Chemically, it is a racemate with the receptor-biocking activity residing in the (-)-isomer, and antiarrhythmic activity shown by both (the (-1-) -S-form is dexsotalol). Therapeutically, it is normally used as an antiarrhythmic rather than as an antihypertensive. sotalol hydrochloride sotalol. soterenol [inn] (soterenol hydrochloride [usan]) is a P-ADRENOCEPTOR AGONIST. Therapeutically, it can be used as a BRONCHODILATOR in ANTIASTHMATIC treatment. 

C. Sotalol, which also has type III antiarrhythmic activity, prolongs the QT interval in a dose-dependent manner and may cause torsade de pointes (see p 14) and ventricular fibrillation. 

The Vaughan-Williams classification of antiarrhythmic drugs has been criticized for a number of reasons. The classification is based on the effects of drugs on normal, rather than diseased, myocardium. In addition, many of the drugs may be placed into more than one class. For example, the class IA drugs prolong repolarization/refractoriness, either via the parent drug8,9 or an active metabolite,10 and therefore also maybe placed in class III. Sotalol is also a 3-blocker, and therefore fits into class II. Amiodarone inhibits sodium and potassium channels, is a non-competitive inhibitor of 3-receptors, and inhibits calcium... 

Singh, B.N. (1990) in A Symposium ControlUng Cardiac Arrhythmias with Sotalol, a Broad-Spectrum Antiarrhythmic with Beta-Blocking Effects and Class III Activity (Singh, B.N., ed.). Am. J. Cardiol. 65 No. 2 pp. 3A-11 A. 

Blockers are antiarrhythmics of class II according to the Vaughan-Williams classification, effective in the treatment of both supraventricular and ventricular tachyarrhythmias. These drugs can also reduce ectopic beats, especially if they are a result of sympathetic activity. Sotalol is a racemic mixture of the -blocking L-isomer and the class III antiarrhythmic D-isomer. This racemic mixture as well as D-sotalol are used as class Ill-antiarrhythmic. 

Sotalol [SOE ta lol], although a class III antiarrhythmic agent, also has potent p-blocker activity. It is well established that p-blockers reduce mortality associated with acute myocardial infarction. 

In contrast, amiodarone and sotalol are effective in most supraventricular and ventricular tachycardias. Amiodarone displays electrophysiologic characteristics consistent with each type of antiarrhythmic drug, ft is a sodium channel blocker with relatively fast on-off kinetics, has nonselec-tive j8-blocking actions, blocks potassium channels, and has slight calcium antagonist activity. The impressive effectiveness and low proarrhythmic potential of amiodarone have challenged the notion that selective ion channel blockade is preferable. Sotalol is a potent inhibitor of outward... 

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