Interactions Between Mivacurium, Rocuronium, and Vecuronium During General Anesthesia

This study was designed to examine the interactions between mivacurium and rocuronium or vecuronium when administered during a standardized anesthetic technique.Seventy healthy women undergoing abdominal hysterectomy procedures with a standardized thiopental-sufentanil-desflurane-nitrous oxide anesthetic technique were randomly assigned to one of seven treatment groups (10 patients each). After a tracheal intubating dose of vecuronium 100 micro gram/kg (Groups 1 and 2), rocuronium 600 micro gram/kg (Groups 3 and 4), or mivacurium 250 micro gram/kg (Groups 5, 6, and 7), patients received vecuronium, 25 micro gram/kg (Groups 1 and 6), rocuronium 150 micro gram/kg (Groups 3 and 7), or mivacurium 50 micro gram/kg (Groups 2, 4, and 5) for maintenance of neuromuscular blockade. Neuromuscular function was assessed using electromyography, with a train-of-four mode of stimulation at the wrist every 10 s. The clinical duration (time for T1 to return to 25% of baseline) of the maintenance dose of mivacurium was significantly longer after an intubating dose of rocuronium (40 +/- 8 min) and vecuronium (28 +/- 6 min) than after mivacurium (12 +/- 3 min). The clinical duration of maintenance doses of vecuronium (18 +/- 6 min) and rocuronium (13 +/- 2 min) were significantly shorter after an intubating dose of mivacurium than that after an intubating dose of vecuronium (30 +/- 5 min) or rocuronium (42 +/- 12 min), respectively. These data suggest that with consecutive administration of neuromuscular blocking drugs, the initial duration of action depends more on the kinetics of the first neuromuscular blocking drug than the subsequent drug. Thus, there appears to be no clinical advantage in using mivacurium for maintenance of neuromuscular blockade after initial administration of rocuronium or vecuronium. (Anesth Analg 1996;83:818-22)