Onset/offset characteristics and intubating conditions of rapacuronium: a comparison with rocuronium

We compared onset and offset of action and tracheal intubating conditions after rapacuronium and rocuronium in 60 patients in a randomized, assessor-blinded study. Following induction of anaesthesia with propofol 2.5 mg kg −1 , either rapacuronium 1.5 mg kg −1 ( n =30) or rocuronium 0.6 mg kg −1 ( n =30) was administered to facilitate tracheal intubation. Anaesthesia was maintained with either a propofol infusion (100 μg kg −1  min −1 ) or sevoflurane (1% end-tidal) with 66% nitrous oxide (N 2 O), n =15 in each subgroup. Neuromuscular monitoring was performed using an electromyographic (EMG) device (Datex Relaxograph). The lag times (mean 42 (sd 11) s and 44 (16) s), maximum block (99 (2)% and 98 (3)%) and intubating conditions at 60 s (good-to-excellent in 86% and 84% of patients) were similar for rapacuronium and rocuronium, respectively. The onset time of rapacuronium was shorter than rocuronium (87 (20) vs 141 (65) s, P vs 50 (27)%, P vs 39.1 (14.2) min, P vs 47.8 (19.0) min, P −1 had a more rapid onset, similar intubating conditions, and shorter recovery times than rocuronium 0.6 mg kg −1 .