Spontaneous or neostigmine-induced recovery after maintenance of neuromuscular block with Org 9487 (rapacuronium) or rocuronium following an initial dose of Org 9487

We have examined spontaneous and neostigmine-induced recovery after an init ial dose of Org 9487 1.5 mg kg(-1) followed by three repeat doses of Org 94 87, a 30-min infusion of Org 9487 or two incremental doses of rocuronium. M ean clinical duration after incremental doses of Org 9487 0.5 mg kg(-1) inc reased from 12.3 (SD 3.4) min to 14.0 (4.0) and 15.9 (5.9) min (P<0.01), an d after rocuronium from 14.4 (5.2) min to 19.2 (5.9) min (P<0.01). Times fo r spontaneous recovery from a TI of 25% to a TOF ratio of 0.8 after the las t bolus dose of Org 9487 and after a 30-min infusion were 72.4 (16.5) and 6 6.1 (26.9) min compared with 36.7 (15.8) min in the group receiving rocuron ium. These times were significantly reduced to 9.9 (4.5), 8.6 (6.1) and 5.7 (2.5) min, respectively, after neostigmine administration at a TI of 25% ( P<0.05). We conclude that administration of Org 9487 by repeat bolus doses or infusion was associated with slow spontaneous recovery but neostigmine a dministration resulted in adequate recovery in less than 10 min.