Methadone maintenance and breastfeeding in the neonatal period.
OBJECTIVE
In a sample of methadone-maintained breastfeeding women and a matched group of formula-feeding women, this study evaluated concentrations of methadone in breast milk among breastfeeding women and concentrations of methadone in maternal and infant plasma in both groups.


METHODS
Eight methadone-maintained (dose: 50-105 mg/day), lactating women provided blood and breast milk specimens on days 1, 2, 3, 4, 14, and 30 after delivery, at the times of trough and peak maternal methadone levels. Paired specimens of foremilk and hindmilk were obtained at each sampling time. Eight matched formula-feeding subjects provided blood samples on the same days. Infant blood samples for both groups were obtained on day 14. Urine toxicological screening between 36 weeks of gestation and 30 days after the birth confirmed that subjects were not using illicit substances in the perinatal period.


RESULTS
Concentrations of methadone in breast milk were low (range: 21.0-462.0 ng/mL) and not related to maternal dose. There was a significant increase in methadone concentrations in breast milk over time for all 4 sampling times. Concentrations of methadone in maternal plasma were not different between groups and were unrelated to maternal dose. Concentrations of methadone in infant plasma were low (range: 2.2-8.1 ng/mL) in all samples. Infants in both groups underwent neurobehavioral assessments on days 3, 14, and 30; there were no significant effects of breastfeeding on neurobehavioral outcomes. Fewer infants in the breastfed group required pharmacotherapy for neonatal abstinence syndrome, but this was not a statistically significant finding.


CONCLUSIONS
Results contribute to the recommendation of breastfeeding for methadone-maintained women.
Jansson
Lauren M
LM
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. ljansson@jhmi.edu
Choo
Robin
R
Velez
Martha L
ML
Harrow
Cheryl
C
Schroeder
Jennifer R
JR
Shakleya
Diaa M
DM
Huestis
Marilyn A
MA
D000328:Adult; D001903:Bottle Feeding; D001942:Breast Feeding; D016022:Case-Control Studies; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008691:Methadone / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008895:Milk, Human / Q000737:chemistry*; D009357:Neonatal Abstinence Syndrome / Q000517:prevention & control*; D049590:Postpartum Period; D011247:Pregnancy; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D008691:Methadone