An antagonist that binds to M1, M2, and M3 muscarinic acetylcholine receptors (Kds = 0.43, 0.54, and 0.69 nM, respectively, for human receptors); decreases acetylcholine-induced contraction of isolated guinea pig trachea in a concentration-dependent manner; confers complete protection against acetylcholine-induced bronchospasms in anesthetized dogs at 1.0 g/L inhaled aerosol,