Effects of olprinone on neuromuscular blockade caused by vecuronium

We studied the effect of olprinone on neuromuscular blockade caused by vecuronium. Thirty women undergoing nitrous oxide-oxygen-isofiurane anesthesia were randomly divided into olprinone (n=15) or control group (n=15). In the olprinone group, the patients received an intravenous initial loading dose of 01- prinone at a rate of 2 ,ug/kg/minute for 5 minutes, followed by a continuous infusion of olprinone at 0.3,ug/kg/minute. In the control group, the patients received normal saline. Thirty minutes after the beginning of the infusion of olprinone or normal saline, vecuronium (0.1 mg/kg) was administered. The degree of neuromus­ cular blockade was monitored electromyographically at the adductor pollicis muscle. The time to the onset of neuromuscular blockade, and to the return of the first, second, third, or fourth response in train-of-four (TOF; TI, T2, T3, or T4, respectively), and the time course of recovery of TI/control did not differ significantly between the groups. After 50-70 minutes of vecuronium, the TOF ratio (T4/T1) in the olprinone group was significantly higher than in the control group. During this period, the mean TOF ratios in the control and olprinone groups were 0.15-0.39 and 0.40-0.57, respectively. In conclusion, olprinone accelerates the recov­ ery of the TOF ratio, and the quickening effect of olprinone on the recovery of the TOF ratio may be apparent 50-70 minutes after vecuronium in anesthetized patients receiving vecuronium.