Objective Adequate data on fentanyl pharmacokinetics in neonates are lacking. The study was performed to compare serum concentrations and clinical outcome between continuous infusion (CI) and intermittent bolus (IB) doses of fentanyl for analgesia and sedation in neonates.
Methods In this open-label randomised controlled trial, neonates requiring 24–48 hours of mechanical ventilation and fentanyl administration were recruited. In CI regimen, 1 mcg/kg loading dose was followed by 1 mcg/kg/hour infusion. In IB regimen, 1mcg/kg/dose was administered every 4 hours.
Maximum six blood samples were collected in 48 hours from each baby at prespecified time points for estimating serum fentanyl concentration. Secondary outcomes were pain scores (Neonatal Infant Pain Scale and Neonatal Pain, Agitation and Sedation Scale for acute and ongoing pain, respectively) and incidence of adverse effects of fentanyl.
Results 100 neonates were recruited, 53 in CI and 47 in IB group. In CI regimen, median (IQR) serum fentanyl concentration was 0.42 (0.35, 0.46) to 0.61 (0.47, 0.89) ng/mL throughout the infusion period. In IB regimen, median (IQR) peak concentration ranged from 2.21 (1.82, 3.55) to 3.61 (2.91, 4.51) ng/mL and trough concentration 0.41 (0.33, 0.48) to 0.97 (0.56, 1.25) ng/mL for various doses.
Median (IQR) peak concentration (Cmax, 3.06 (1.09, 4.50) vs 0.78 (0.49, 1.73) ng/mL; p<0.001) was significantly higher and area under concentration-time curve (AUC0–24, 19.6 (10.4, 33.5) vs 13.2 (10.8, 22.6) µg·hour/L; p=0.12) was higher (though not statistically significant) in IB than CI regimen. Pain scores and adverse effects were comparable between the two regimens.
Conclusion CI regimen of fentanyl produces steady serum concentrations, whereas IB regimen produces wide fluctuations in serum concentration with high-peak concentrations. A serum fentanyl concentration of 0.4–0.6 ng/mL produces adequate analgesia and sedation in neonates.
Trial registration number CTRI/2014/11/005190.
- pain score
- continuous infusion
- intermittent bolus doses
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Contributors TA conceptualised and designed the study, collected and analysed data, and drafted, reviewed and revised the manuscript. SKM and BSM designed the study, analysed data, and reviewed and revised the manuscript. MPS and MK contributed to study design, collected and analysed data, and reviewed and revised the manuscript. GA contributed to study design, estimated serum fentanyl concentrations, and reviewed and revised the manuscript. VJ contributed to study design, analysed data, and reviewed and revised the manuscript. KAK conceptualised and designed the study, coordinated and supervised the conduct of the study, analysed data, and critically reviewed and revised the manuscript.
Funding The study was supported by the research funds of Christian Medical College Vellore and the Department of Neonatology.
Competing interests None declared.
Patient consent Not required.
Ethics approval Christian Medical College Vellore Institutional Review Board
Provenance and peer review Not commissioned; externally peer reviewed.