Atropine-edrophonium mixture: a dose-response study.

The dose-response and the doses required to prevent bradycardia in 50% (ED50) and 95% (ED95) of patients were determined for atropine after antagonism of pancuronium-induced neuromuscular blockade in 72 patients with edrophonium-atropine mixtures. Edrophonium 0.67 mg/kg (group A, n = 37) or 1.0 mg/kg (group B, n = 35) was randomly mixed with one of seven doses of atropine (ranging from 0.0125 to 0.0215 mg/kg in group A and from 0.02 to 0.04 mg/kg in group B); with dose-response curves for atropine being constructed for both groups 5 and 10 minutes after the injection of the mixture. These dose-response curves were found to be parallel in both groups. The calculated ED50 values of atropine were 1.6-2 times greater in group B, compared with those in group A. The estimated ED50 doses of atropine in groups A and B at 5 minutes were 0.018 and 0.029 mg/kg, respectively, and at 10 minutes, the ED50 doses were similar, being 0.016 and 0.032 mg/kg, respectively. The calculated ED95 doses of atropine in groups A and B at 5 minutes were 0.024 and 0.055 mg/kg, and at 10 minutes, the ED95 doses were also similar, being 0.027 and 0.05 mg/kg, respectively.