Dose-response and time-course of effect of rocuronium bromide in paediatric patients.

We determined dose-response curves and spontaneous recovery of neuromuscular function following a single ED95 dose of rocuronium in 10 infants (1-11 months old), 20 children (2-12 years old) and 20 adults (20-40 years old) during nitrous oxide-oxygen-thiopentone-alfentanil anaesthesia. Neuromuscular block was recorded as adductor pollicis EMG following a supramaximal train-of-four ulnar nerve stimuli at 10 s intervals. ED95 values were significantly less for infants than for children or adults (255 +/- 62, 402 +/- 68 and 350 +/- 78 micrograms kg-1, respectively, P = 0.0001). Time-course of recovery from an average 94% neuromuscular block was similar in all age groups with a 25-75% recovery time of 6.5 +/- 1.8, 5.7 +/- 1.8 and 6.7 +/- 1.6 min in infants, children and adults, respectively. Thus, rocuronium is an intermediate-acting muscle relaxant in all age groups.