Pharmacokinetics of sufentanil in general surgical patients under different conditions of anaesthesia

The pharmacokinetics of sufentanil were studied in 56 surgical patients after an intravenous bolus of 2 μg kg^-1, in association with neurolept analgesia or volatile anaesthetics (halothane, enflurane and isoflurane). Plasma concentrations of sufentanil were measured by radioimmunoassay. The kinetics of sufentanil were comparable under neurolept analgesia and under anaesthesia with halothane, enflurane or isoflurane. The overall mean elimination half-life was 182 min, Vd⁸⁵ 169 1 and the plasma clearance 910 ml min^-1. Except for the isoflurane subgroup, there was no significant correlation between half-life, the volume of distribution or clearance with age (24–77 years) or body weight (45–95 kg).