Pharmacokinetics of intrarectal nalbuphine in children undergoing general anaesthesia.
The pharmacokinetics of nalbuphine (0.3 mg/kg) administered by the rectal route were studied in ten children undergoing general anaesthesia for minor surgery. Blood sampling was carried out for 8 h after rectal administration and plasma drug concentrations were measured by high performance liquid chromatography using electrochemical detection after an optimized solid-phase extraction procedure. The mean time to achieve the maximum plasma concentration (Cmax = 24 +/- 15 ng/mL) was 25 +/- 11 min and the elimination half-life was 2.7 +/- 0.7 h. The coefficients of variation for Cmax and the concentration-time curve (AUC) were 62 and 68%, respectively. Although rectal absorption is considered irregular, the large intersubject variability is also explainable by a variable hepatic bypass for a drug, like nalbuphine, that undergoes extensive first-pass metabolism. No problem of analgesic efficacy or of local tolerance was reported. In conclusion, the rectal route of administration provides a rapid and reliable absorption of nalbuphine.
Bessard
G
G
Laboratoire de Pharmacologie, Hôpital Michallon, CHU de Grenoble, France.
Alibeu
J P
JP
Cartal
M
M
Nicolle
E
E
Serre Debeauvais
F
F
Devillier
P
P
D000285:Administration, Rectal; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000768:Anesthesia, General; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009266:Nalbuphine / Q000008:administration & dosage / Q000493:pharmacokinetics*
D000701:Analgesics, Opioid; D009266:Nalbuphine