A β2-AR agonist; selectively binds to β1- over β2-ARs (Kds = 2.9 and 113 nM, respectively) as well as β3-adrenergic, B2 bradykinin, NK1 and NK2 receptors up to 3 μM; induces cAMP accumulation in cultured human bronchial epithelial cells; relaxes guinea pig tracheal strips precontracted with carbamoylcholine, ovalbumin, or histamine (pD2s = 8.4, 9.5, and 9.5, respectively); reverses histamine- and ovalbumin-induced bronchoconstriction in guinea pigs (ED50s = 1 and 40 nmol/kg, respectively)