A β2-AR agonist (Kd = 759 nM in a radioligand binding assay using CHO cells expressing the human receptor); selective for β2-ARs over β1- and β3-ARs (Kds = 46.8 and 21.9 μM, respectively); reduces acetylcholine-induced bronchospasm in anesthetized guinea pigs (25-50 μg/kg, i.v.); reduces response of bronchial muscle to efferent vagal stimulation in anesthetized cats and dogs (1-2.5 and 10-20 μg/kg, i.v., respectively); reduces transpulmonary pressure in recurrent airway obstruction-affected horses (EC50 = 39.7 μg)