Optimal time interval between pretreatment with alcuronium and suxamethonium during anaesthetic induction.

Alcuronium 0.03 mg/kg was studied in a double-blind randomized fashion as a pretreatment before suxamethonium using different time intervals between the administration of the drugs in 78 patients (ASA I-II) undergoing otolaryngological surgery. Alcuronium was given 1, 2 or 3 min before suxamethonium 1.5 mg/kg. The control group received saline as a pretreatment and suxamethonium 1 mg/kg. Anaesthesia was induced with thiopental 5.5 mg/kg over 60 s. Muscle fasciculations, intubating conditions, cardiovascular responses to endotracheal intubation and duration of neuromuscular block were assessed. Muscle fasciculations were statistically and similarly inhibited (P less than 0.01) at all time intervals between alcuronium and suxamethonium. Intubating conditions were worse (P less than 0.05) in the 3-min group than in the other groups. Cardiovascular responses to endotracheal intubation were similar in all groups. The neuromuscular block after suxamethonium was significantly shorter (P less than 0.05) in the 2- and 3-min groups than in the other groups. In conclusion, from the clinical point of view the 1-min time interval between alcuronium and suxamethonium is optimal since muscle fasciculations are inhibited and intubating conditions are satisfactory.