Neonatal Abstinence Syndrome Management: Comparison of Morphine Versus Methadone Weaning Protocols

Abstract

Introduction: Neonatal abstinence syndrome (NAS) from in-utero opioid exposure affects thousands annually. Morphine is first-line in many centers, but methadone is used due to longer half-life possibly enabling shorter weaning. No consensus exists on optimal agent.

Methods: Systematic review of RCTs and quasi-experimental studies comparing morphine to methadone for NAS treatment (Finnegan score-directed). Databases: CENTRAL, Embase, PsycINFO. Primary outcomes: length of hospital stay (LOS), duration of pharmacological treatment. Secondary: need for adjunctive phenobarbital, peak Finnegan score. Random-effects meta-analysis.

Results: Seven studies (n=972 neonates) were included: 4 RCTs, 3 retrospective cohort. Methadone significantly reduced LOS (mean difference –6.8 days, 95% CI –10.2 to –3.4, p<0.001) and treatment duration (–7.1 days, 95% CI –11.3 to –2.9). Need for adjunctive phenobarbital was similar (RR 0.86, 95% CI 0.65–1.14). Peak Finnegan scores were lower with methadone (–2.4 points, p=0.02). No differences in adverse events (seizures, respiratory depression).

Discussion: Methadone appears superior to morphine for NAS, shortening hospitalization by nearly one week. The longer half-life provides smoother drug levels, reducing peak withdrawal severity. Limitations: marked heterogeneity in weaning protocols and inclusion of polysubstance exposures. Most studies excluded NAS from buprenorphine.

Conclusions: Methadone should be considered first-line pharmacotherapy for neonatal abstinence syndrome, particularly in centers with high NAS volume and ability to monitor prolonged half-life. Individualized weaning still required.