Clinical study of interaction between rocuronium and some commonly used antimicrobial agents

The onset and duration of clinical relaxation and reversibility of rocuronium bromide (ORG 9426) 0.6 mg kg-1 were studied following administration of netilmicin 2 mg kg-1 (n = 10) or cefuroxime 20 mg kg-1 (n = 10) in patients undergoing urological surgery; and cefuroxime 20 mg kg-1 (n = 10) metronidazole 7.5 mg kg-1 (n = 10), metronidazole 7.5 mg kg-1 and cefuroxime 20 mg kg-1 (n = 10), or placebo (n = 10) in patients undergoing abdominal surgery under anaesthesia with thiopentone, nitrous oxide in oxygen, fentanyl and halothane. The antimicrobial agents were administered intravenously 5 min before rocuronium. Neuromuscular function was monitored using mechanomyography and train-of-four (TOF) mode of stimulation. Onset of neuromuscular block occurred in approximately 60 s with all patients achieving complete block. The mean clinical duration (+/- SD) was 50 +/- 10.7 and 44 +/- 6.7 min following netilmicin and cefuroxime respectively in patients undergoing urological surgery; and 49 +/- 13.7, 44 +/- 11.1, 48 +/- 11.1 and 38 +/- 7.3 min in the groups undergoing abdominal surgery receiving cefuroxime, metronidazole, cefuroxime and metronidazole combination and placebo respectively. There were no statistically significant differences between the groups in either the onset or the duration of clinical relaxation. Reversal of neuromuscular block with neostigmine carried out at spontaneous recovery of T1 (first response in the TOF) of 25% or more was easily achieved in all groups in 2-4 min. It is concluded that there is no significant interaction between rocuronium and single doses of the antimicrobial agents used in the present study.