Labetalol

Labetalol (HCl) is oral and parenteral competitive cocdirselective ß -adrenergic and selective postsynaptic a-1 adrenergic receptor blocker. Due to the presence of two optical centers, there are four diastereoisomers of labetolol, each of which displays different relative activities. The drug mixture possesses three to seven times greater ß -blocking activity than a-1 -blocking activity. Labetalol is clinically used in the treatment of hypertension associated with a variety of conditions. Labetalol was approved by the FDA for use in August 1984. Labetalol (HCl) is a reversible ß blocker with concurrent a1 blocking actions that produces peripheral vasodialation.lt blocks ß1-receptors in the heart, ß 2-receptors in bronchial and vascular smooth muscle, and a 1receptors in vascular smooth muscle. The ß-blocking activity is three to seven times as potent as the a-blocking ability.The result of labetalol's actions at a- and ß-receptors leads to vasodilation and decreased total peripheral resistance, which results in decreased blood pressure without a substantial decrease in resting heart rate, cardiac output, or stroke volume