RELATIONSHIPS BETWEEN MATERNAL METHADONE DOSAGE, MATERNAL-NEONATAL METHADONE LEVELS, AND NEONATAL WITHDRAWAL

Objective: To define the relationships between neonatal opiate withdra wal and drug-related factors such as maternal methadone dosage, matern al and neonatal plasma levels, and rate of decline of methadone in neo natal plasma. Methods: Twenty-one methadone-dependent women and their newborn infants were studied. Fourteen of the women used other illicit drugs. The severity of neonatal withdrawal was assessed with a standa rdized scoring system. Venous blood samples for methadone levels were collected from the mothers within 24 hours of delivery and from their newborns within 24 hours of birth and on day 3-4 of life. Results: The maternal methadone dosage at delivery correlated significantly with t he maternal plasma level drawn at 16 hours postpartum (r = 0.512, P < .05), and the maternal methadone level in turn correlated significantl y with the neonatal plasma methadone level on day 1 of life (r = 0.545 , P < .05). A positive correlation was found between the severity of c entral nervous system signs of withdrawal and the rate of decline of t he neonatal plasma methadone level from day 1 to day 4 of life (r = 0. 550, P < .05). Conclusion: This spectrum of relationships supports the concept that careful reduction of the maternal methadone dosage durin g pregnancy under intensive medical and psychosocial surveillance may benefit the drug-exposed newborn infant clinically.