Sotalol (STL)

Sotalol is a drug used in individuals with rhythm disturbances (cardiac arrhythmias) of the heart, and to treat hypertension in some individuals. It is a non-selective competitive β-adrenergic receptor blocker that also exhibits Class III antiarrhythmic properties by its inhibition of potassium channels. Sotalol non-selectively binds to both β1- and β2-adrenergic receptors preventing activation of the receptors by their stimulatory ligand1. Without the binding of this ligand to the receptor, the G-protein complex associated with the receptor cannot activate production of cyclic AMP, which is responsible for turning on calcium inflow channels. A decrease in activation of calcium channels will therefore result in a decrease in intracellular calcium. In cardiac cells, calcium is important in generating electrical signals for contraction, as well as generating force for contraction.