Plasma concentrations of fentanyl in infants, children and adults

Abstract

To evaluate whether there are age-related differences in the plasma concentration-vs-time course of fentanyl, the authors administered fentanyl to seven infants (3-10 months), seven children (1-9 years) and seven adults (18-41 years). Anaesthesia was induced with thiopentone, nitrous oxide, and pancuronium; following tracheal intubation, fentanyl (approximately 30 micrograms X kg-1 for infants and children, 20 micrograms X kg-1 for adults) was administered as a 2-min IV infusion. Anaesthesia was maintained with nitrous oxide, pancuronium, and morphine sulphate as clinically indicated. Plasma samples were obtained for 4 h and fentanyl concentrations determined by radioimmunoassay. Plasma concentrations per microgram X kg-1 fentanyl administered were lowest in infants 4-10 and 60-240 min after the start of the 2-min infusion; values for children were lower than those for adults 4, 180 and 210 min after the start of the 2-min infusion. These findings are consistent with the authors' clinical observation that infants tolerate larger doses of fentanyl than do adults.

Assessment of small‐dose fentanyl and sufentanil blunting the cardiovascular responses to laryngoscopy and intubation in children

“…The difference in ability of fentanyl to blunt the cardiovascular intubation response between children in our study and adults in a previous study is possibly related to pharmacokinetic differences. Singleton et al (21) found that after bolus administration of fentanyl, infants had significantly lower plasma fentanyl concentrations compared with adults, whereas children aged 1–9 years had intermediate plasma levels. This indicates that children may require a higher dose of fentanyl to achieve the same effect compared with adults.…”

Effect site concentrations of propofol producing hypnosis in children and adults: comparison using the bispectral index

“…Higher requirements of anaesthetic drugs in children than in adults (9, 10, 20–22) may be secondary to pharmacokinetic and/or pharmacodynamic factors. In the case of propofol, paediatric pharmacokinetic models do consider pharmacokinetic differences (13, 23), and ‘more’ propofol is administered in children than in adults to obtain a given concentration.…”

Pragmatic pharmacology: population pharmacokinetic analysis of fentanyl using remnant samples from children after cardiac surgery

“…Fentanyl pharmacokinetic (PK) data for paediatric patients are limited. Studies to date indicate that fentanyl clearance is age dependent , affected by cardiac surgery and highly variable . One barrier to further study of the factors influencing this variability is the need for serial invasive blood sampling for PK analysis.…”