A β-adrenergic receptor antagonist (Kds = 6.91, 0.832, and 117.49 nM for human β1-, β2-, and β3-ARs, respectively); reduces mean blood pressure, resting heart rate, and contractility and increases AV conduction time in dogs; restores normal sinus rhythm in dogs with ouabain-induced arrhythmias (ED50 = 3.8 mg/kg); acts as a non-specific serotonin receptor antagonist, reducing tranylcypromine/L-tryptophan-induced hyperactivity in rats,