[Can nicardipine potentiate vecuronium induced neuromuscular blockade?]

The effects of intravenous nicardipine on the neuromuscular blockade produced by single bolus injection of vecuronium were studied in surgical patients undergoing tracheal intubation. We measured the mechanical response of the abductor pollicis muscle to stimulation of the ulnar nerve in a train-of-four sequence at 2 Hz and recorded the amplitudes of the first response (T1). Anesthesia was induced with thiopental 5 mg.kg-1 with or without nicardipine 10 micrograms.kg-1 followed by injection of vecuronium in a dose of either 0.1 or 0.15 mg.kg-1. Onset and duration of neuromuscular blockade were judged by percent depression of T1. The time intervals for 90% and 100% depression in T1 seen in patients who had received vecuronium 0.1 mg.kg-1 with nicardipine (n = 10) were 157.0 +/- 30.8 sec and 192.3 +/- 31.2 sec (mean +/- SD), respectively. These values were significantly shorter than those observed in patients without nicardipine administration (n = 10, P less than 0.05), and were not significantly different from the values in patients who had received vecuronium 0.15 mg.kg-1 (n = 10). On the other hand, the time for 25% recovery in T1 was uninfluenced by nicardipine. Present study indicates that nicardipine pretreatment possibly shortens the onset time after minor or moderate dose of vecuronium.