Cardiac effects of atropine and gallamine in patients receiving suxamethonium.

Eighty healthy patients were randomly allocated to four groups. Atropine 0.01 mg kg-1 i.v. (group I), gallamine 0.3 mg kg-1 i.v. (group II), atropine 0.01 mg kg-1 i.m. and gallamine 0.3 mg kg-1 i.v. (group III), or atropine 0.01 mg kg-1 i.v. and gallamine 0.3 mg kg-1 i.v. (group IV) were given before operation. After induction of anesthesia with thiopentone, suxamethonium 1 mg kg-1 was given i.v. The lungs were ventilated with halothane in nitrous oxide in oxygen. Five minutes later the same dose of suxamethonium was repeated. E.c.g. was monitored continuously. No serious bradycardia was observed following a second injection of suxamethonium in any group. The results suggest that thiopentone protects against suxamethonium-induced bradycardia during halothane anaesthesia.