A β-adrenergic receptor antagonist (Kd = 13 nM); blocks isoproterenol-induced increases in heart rate, contractile force, and blood pressure in vagotomized dogs (ED50s = 2.3, 3.1, and 1.8 UG/kg, respectively); the (R) and (S)-enantiomers EAch reduce intraocular pressure in rabbits (1% solution)