[Cumulative pharmacokinetics and clinical effects of nalbuphine in patients in the postoperative phase. An open multicenter study].

Pharmacokinetic data and analgetic potency of nalbuphine hydrochloride (Nubain) under conditions of postoperative respiratory treatment and repeated dosage was investigated in a multicenter study. Patients received 20 mg nalbuphine intravenously at intervals of 3 h. Blood samples for analysis of nalbuphine plasma concentration were taken after the first injection, immediately before further medication and after the last one. Data were fitted to 2-compartment model using non-linear fit procedures. The half-life time in plasma was slightly shorter than in other studies, while the peak plasma concentrations were comparable with other results in the literature. There was no cumulation of the substance found in this study. Clinically the antagonistic effect of nalbuphine was mainly observed after neuroleptic anaesthesia. In these cases additional injections of further analgetic and sedative drugs were necessary. The clinical effect was mostly considered to be good or satisfactory. Less satisfactory effects were due to the 3 h time distance between repeated dosage. Shorter intervals could be discussed and used because of the absence of cumulation of nalbuphine in this study.