Labetalol

Labetalol is a diastereoisomeric mixture containing approximately equal amounts of all four possible stereoisomers: (R,S)-labetolol, (S,R)-labetolol, (S,S)-labetalol, and (R,R)-labetalol. It is an adrenergic antagonist used to treat high blood pressure, acting as an antihypertensive, sympatholytic, alpha-adrenergic, and beta-adrenergic antagonist.