Pipecuronium bromide (Arduan) is a bisquaternary, steroid-type neuromuscular blocking agent in clinical use in Eastern Europe. Before its introduction into clinical practice in the USA, in the first phase of this study the neuromuscular potency of pipecuronium was determined under "balanced" and enflurane anaesthesia by the cumulative log dose-response method in 30 patients each. In the second phase the intubation and onset times, clinical duration of the first and repeated doses, spontaneous recovery index, reversibility of its residual neuromuscular effect by an anticholinesterase and its effect on heart rate and blood pressure was compared with the same variables observed in patients, anaesthetized with identical techniques but who had received vecuronium or pancuronium. The neuromuscular potency of pipécuronium was greater under enflurane [ED95 = 23.6 ± 1.1 μg · kg-1 (mean ± SEM)] than under balanced (ED95 = 35.1 ± 17 μg · kg-1) anaesthesia. Pipecuronium was more potent than vecuronium under both balanced (ED95 = 45.8 μg · kg-1) and enflurane anaesthesia (ED95 = 27 A μg · kg-1). Following the administration of 2 × ED95 doses there were no clinically significant differences in the intubation or onset times of pipecuronium, vecuronium and pancuronium. Under balanced anaesthesia the clinical duration of 2 × ED95 dose of pipécuronium (110.5 ± 0.3 min) or pancuronium (115.8 ± 8.1 min) were similar and about three times longer than that of vecuronium (36.3 ± 2.1 min). The recovery indices of pipécuronium (44.5 ± 8.2 min) and pancuronium (41.3 ± 4.2 min) were also similar and about three times longer than that of vecuronium (14.3 ± 1.4 min). Residual neuromuscular block of the three muscle relaxants could be equally well reversed by anticholinesterases at the end of anaesthesia. The 2 × ED95 doses of pipécuronium or vecuronium had no significant effect on heart rate or blood pressure. Pancuronium increased heart rate by about 20 per cent. Pipecuronium is preferable to pancuronium for the production of muscular relaxation for relatively long operations, when it is desirable to avoid acceleration of heart rate. © 1990 Canadian Anesthesiologists.
