Alpha- and beta-blocking agents: pharmacology and properties

Adrenergic receptors have been separated into alpha and beta groups, which have then been further subdivided. Agents have been developed that block each type of receptor with varying degrees of specificity between the sub-types, leading to differences in pharmacodynamic profile. A more recent innovation has been the development of multiple action beta-blocking drugs, ie, those not only blocking the beta receptors but also possessing a peripheral vasodilator effect that may be due to alpha blockade, beta-2 stimulation, or a vasodilator action independent of either alpha or beta receptors.