A non-selective β-adrenergic receptor antagonist (Kds = 1.78, 0.4, and 5.01 nM for β1-, β2-, and β3-ARs, respectively); also binds to α1-, but not α2-, adrenergic receptors (Kis = 0.81 and 3,400 nM, respectively); reverses increases in heart rate induced by isoproterenol in isolated guinea pig atria (Kb = 0.8 nM); induces relaxation of isolated precontracted guinea pig trachea (Kb = 1.3 nM); prevents epinephrine-induced premature ventricular beats in a rat model of arrhythmia (IC50 = 0.25 mg/kg); inhibits the contractile response to norepinephrine in isolated rabbit aorta (Kb = 11 nM); decreases systolic blood pressure and heart rate in rat models of hypertension at 3-30 mg/kg