An antagonist of nAChRs and muscarinic M2 and M3 receptors (ED50s = 0.08, 0.3, and 0.1 mg/kg for ex vivo human skeletal muscle nAChRs, guinea pig cardiac M2 receptors, and guinea pig bronchial M3 receptors, respectively); inhibits acetylcholine-induced activation of neuronal nAChRs (IC50s = 69.04, 3.71, 1.52, and 2.90 for human α3β2-, α3β4-, α4β2-, and α7-containing nAChRs expressed in Xenopus oocytes); inhibits adult human muscular α1β1εδ-containing nAChRs (IC50 = 3.69 nM in Xenopus oocytes expressing the human recombinant receptor); inhibits bradycardia and bronchoconstriction induced by vagal stimulation or acetylcholine in guinea pigs; induces neuromuscular blockade in sheep (ED95 = 80 μg/kg)