Rocuronium- and mivacurium-induced neuromuscular block and intubating conditions: a comparison with vecuronium.

The time-course of action after an initial 2 x ED90 dose and after maintenance doses of 0.5 x ED90, and intubating conditions at 90 s after a 2 x ED90 dose following rocuronium, vecuronium and mivacurium were evaluated in anaesthetized adult patients. Neuromuscular measurements were performed with mechanomyography. Rocuronium produced a significantly deeper neuromuscular block at 90 s (mean and (standard deviation)) (91 (11%), compared to vecuronium (61 (22%)%) and mivacurium (58 (23)%). The onset time following rocuronium (172 (71)s) was significantly shorter than that following mivacurium (229 (60)s). At 90 s, intubating conditions were significantly better in the rocuronium group than in the vecuronium or mivacurium group. Mivacurium offered a significantly faster recovery of neuromuscular block following the 2 x ED90 dose and following an average of 45 min of clinical muscle relaxation (single twitch response < or = 25%) compared to rocuronium and vecuronium: clinical duration 13 (4), 28 (9) and 33 (9) min, respectively, and recovery time from 25 to 75% recovery of the single twitch response: 6 (2), 11 (4) and 14 (7) min, respectively.