Evaluation of Fentanyl-Emerged Adverse Events and Pharmacokinetics in Neonates: A Physiologically Based Pharmacokinetic Modeling Approach.

Background: Despite its common use for analgesia in neonatal intensive care units, the optimal dosing and safety profile of fentanyl, particularly regarding suspected fentanyl-emerged adverse events (FEAEs), such as hypotension, desaturation, and oliguria, are not well-defined.

Objective: This study aimed to develop an optimal therapeutic monitoring and dosing strategy for fentanyl for neonates. A physiologically based pharmacokinetic (PBPK) model for predicting fentanyl pharmacokinetics across various populations, including preterm and term neonates, was developed, and the relationship between predicted fentanyl exposure and FEAE incidence in neonates was assessed.

Methods: A PBPK model was developed and validated against the observed values in the literature. The model's predictive accuracy for fentanyl pharmacokinetics and association with FEAE incidence in an external retrospective cohort of Japanese neonates was evaluated using the predicted concentrations and pharmacokinetic parameters estimated by PBPK simulation.

Results: The PBPK model exhibited reasonable predictive performance for serum fentanyl concentrations in actual neonatal patients (mean error: 9.27% [standard error: 5.06%], root mean squared error: 54.7%). The incidence of any FEAE, particularly oxygen desaturation, was associated with the fentanyl concentration-to-dose ratio, but not with some exposure parameters, such as the area under the curve and maximum concentration. The recommended reduced infusion rate allowed serum fentanyl concentrations to fall within the ranges established by the reported values and our data.

Conclusions: Our PBPK model and proposed dosing strategy may contribute to safer and more effective fentanyl use in neonates.