Rocuronium prevents succinylcholine-induced fasciculations

Purpose: The aim of this study was to assess the effect of rocuronium pretreatment at 3 and 1.5 min before succinylcholine administration on fasciculations, neuromuscular blockade and intubating conditions. Methods: Sixty ASA I or II adults scheduled for elective surgery were anaesthetised with midazolam, fentanyl, propofol, N₂O and isoflurane. They were randomised in a double blind manner into three groups: group ROC-3 min (n = 22) received 0.05 mg·kg^-1 rocuronium, 3 min before 2 mg·kg^-1 succinylcholine; group ROC-1.5 min (n = 20) received 0.05 mg·kg^-1 rocuronium 1.5 min before 2 mg·kg^-1 succinylcholine; and group NO ROC (n = 18) had no rocuronium before injection of 2 mg·kg^-1 succinylcholine. Fasciculations and intubating conditions were evaluated by the same physician who was unaware of the randomisation. Neuromuscular block was measured at the adductor pollicis with an accelerometer. Results: The incidence of fasciculations was lower in the ROC-3 min (9%) and ROC-1.5 min (30%) groups than in the NO ROC group (83%; P < 0.001). The intensity of fasciculations was also less in both pretreatment groups. No statistical difference was noted between pretreatment at 3 and 1.5 min. Intubating conditions, onset time and duration of succinylcholine blockade were comparable in all three groups. Conclusion: The incidence and severity of succinylcholine fasciculations can be reduced by giving 0.05 mg·kg^-1 rocuronium either 1.5 min or 3 min before succinylcholine. The effects of 2 mg·kg^-1 succinylcholine with rocuronium pretreatment, and 1 mg·kg^-1 succinylcholine, without pretreatment, are similar with respect to intubating conditions, onset of paralysis and duration of blockade.