Comparison of Two Morphine Dosing Strategies in the Management of Neonatal Abstinence Syndrome

J Pediatr Pharmacol Ther. 2022;27(2):151-156. doi: 10.5863/1551-6776-27.2.151. Epub 2022 Feb 9.


Objective: The incidence of neonatal abstinence syndrome (NAS) has increased in recent years. Treatment approaches usually involve opioid replacement; however, the optimal treatment strategy is unknown. This study sought to determine the impact of weight- and symptom-based morphine dosing strategies on LOS and medication exposure in patients with NAS.

Methods: A retrospective review was conducted from May 2015 to June 2017 at 2 NICUs within a health-system using different dosing approaches for NAS. Data were compared using Fisher exact tests for categorical data and t tests and Wilcoxon ranked sums for continuous data.

Results: Baseline demographics were well-matched except for postmenstrual age at morphine initiation (p = 0.04). The weight-based group had a larger initial morphine dose (p < 0.001) and fewer number of steps to maximum morphine dose (p = 0.009). There were no differences between groups in LOS, number of dose adjustments, doses administered, weaning steps, maximum dose, or need to re-escalate dosing. There was also no difference between the first 3 modified Finnegan scores (MFS) after transferring patients to a neonatology service. Neonates with symptom-based dosing had a higher maximum MFS (p = 0.024). Neonates in the symptom-based group required adjunct therapy more often (p < 0.0001).

Conclusions: Data indicate the dosing strategy impacts number of steps to reach maximum dose and need for adjunctive therapy. Weight-based dosing may decrease the number of steps required to reach the morphine maximum dose and the need for adjunctive therapy by controlling NAS symptoms earlier.

Keywords: NAS; morphine; neonatal abstinence syndrome; withdrawal.