Drug Groups

approved

Description

An adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias. [PubChem]

Indication

For the maintenance of normal sinus rhythm [delay in time to recurrence of atrial fibrillation/atrial flutter (AFIB/AFL)] in patients with symptomatic AFIB/AFL who are currently in sinus rhythm. Also for the treatment of documented life-threatening ventricular arrhythmias.

Pharmacology

Sotalol is an antiarrhythmic drug. It falls into the class of beta blockers (and class II antiarrhythmic agents) because of its primary action on the β-adrenergic receptors in the heart. In addition to its actions on the beta receptors in the heart, sotalol inhibits the inward potassium ion channels of the heart. In so doing, sotalol prolongs repolarization, therefore lengthening the QT interval and decreasing automaticity. It also slows atrioventricular (AV) nodal conduction. Because of these actions on the cardiac action potential, it is also considered a class III antiarrhythmic agent. The beta-blocking effect of sotalol is non-cardioselective, half maximal at about 80mg/day and maximal at doses between 320 and 640 mg/day. Sotalol does not have partial agonist or membrane stabilizing activity. Although significant beta-blockade occurs at oral doses as low as 25 mg, significant Class Ieffects are seen only at daily doses of 160 mg and above.

Toxicity

The most common signs to be expected are bradycardia, congestive heart failure, hypotension, bronchospasm and hypoglycemia. In cases of massive intentional overdosage (2-16 grams) of sotalol the following clinical findings were seen: hypotension, bradycardia, cardiac asystole, prolongation of QT interval, Torsade de Pointes, ventricular tachy-cardia, and premature ventricular complexes.

Affected Organisms

Biotransformation

Sotalol is not metabolized.

Absorption

In healthy subjects, the oral bioavailability of sotalol is 90-100%. Absorption is reduced by approximately 20% compared to fasting when administered with a standard meal.

Half Life

Mean elimination half-life is 12 hours. Impaired renal function in geriatric patients can increase the terminal elimination half-life.

Protein Binding

Sotalol does not bind to plasma proteins.

Elimination

Excretion is predominantly via the kidney in the unchanged form. Sotalol is excreted in the milk of laboratory animals and has been reported to be present in human milk.

References

External Links