Pharmacokinetics after a single intravenous dose of the opioid ketobemidone in neonates
Acta Anaesthesiologica Scandinavica, 07/27/2012  Clinical Article

Lundeberg S et al. – Compared with the previous study in children older than 1year of age, the elimination of ketobemidone appeared to be slower in full–term neonates. Despite a low pharmacokinetic variability of ketobemidone as observed in the present neonatal patient population, the authors recommend individualizing the dose of ketobemidone based on observations of analgesic efficacy.

• Fifteen full–term neonates (eight females) from 37 gestational weeks at birth and scheduled for elective surgery were included in the trial.
• Their median age was 3days (range 1–18days).
• Ketobemidone hydrochloride was administered as a single intravenous bolus dose, and ketobemidone concentrations were measured by liquid chromatography–mass spectrometry over 10h.
• Pharmacokinetic parameters were calculated with standard compartmental methods.

• The median (range) values for ketobemidone clearance, apparent volume of distribution, volume of central compartment, distribution half–life and elimination half–life were 0.46 (0.23–0.84)l/h/kg, 4.64 (3.50–7.31)l/kg, 1.71 (0.16–3.47)l/kg, 2.85 (1.04–10.78)min and 7.26 (3.5–11.3)h.