Is Methadone safe while breastfeeding?

Effects on the breastfed infant

One center reported 10 women who breastfed during methadone maintenance with no observed adverse effects in their infants.[ 24 ] The death of a 5-week-old infant who was born 1 week prematurely to a former heroin-abusing mother was possibly related to methadone in breastmilk. The infant had been breastfeeding since birth, and the mother was taking an unreported daily dose of oral methadone maintenance. The medical examiner's diagnosis was methadone intoxication. A high level of methadone was found in the infant's serum at autopsy; however, the high level might have been caused by postpartum redistribution (which can be 2- to 10-fold [ 38 ]). The infant was also noted to be "obviously malnourished." Abnormal brain, liver and other organs on autopsy were also found and it appeared that the infant had been neglected.[ 39 , 40 ] Three breastfed term infants of mothers taking oral methadone maintenance 45 to 70 mg daily during pregnancy and lactation had no reported adverse effects. They were cared for in a well-baby nursery after birth and discharged in good health home with their mothers at 2 to 3 days of age. At follow up over 3 weeks to 6 months of age, the infants had no symptoms of sedation or methadone withdrawal while breastfeeding. One infant who had breastfeeding discontinued at 3 weeks of age developed withdrawal symptoms of hyperirritability and sleeplessness. The other 2 infants were slowly weaned over 4 to 6 months and did not experience withdrawal upon breastfeeding discontinuation. The authors cautioned against abrupt breastfeeding discontinuation during methadone maintenance.[ 27 ] A partially breastfed 3.5-month-old infant of a mother taking oral methadone maintenance 73 mg once daily died of sudden infant death syndrome. The mother was mostly bottle feeding the infant due to diminished milk supply. There was no methadone detected in the infant's blood at autopsy (lower limit of the assay not reported).[ 26 ] Twelve full-term breastfed (extent not state

Effects on milk supply

Methadone can increase serum prolactin.[ 60 ] However, the prolactin level in a mother with established lactation may not affect her ability to breastfeed. In a French multicenter prospective study of 246 pregnant women in receiving either methadone or buprenorphine for opiate dependency, 93 women were receiving methadone. Twenty-four percent of women receiving methadone breastfed their infants, which was not different from those receiving buprenorphine.[ 61 ] Successful breastfeeding was reported in New Zealand in 15 infants whose mothers were taking methadone for pain and 18 infants whose mothers were taking methadone for maintenance of narcotic abstinence. Both groups of mothers were taking a wide range of doses with median daily dosages of 40 and 60 mg, respectively. An additional 8 infants were bottle-fed and the feeding method was unknown in 2.[ 62 ] A woman who was not breastfeeding, but who had 2 children (breastfeeding history not stated), was prescribed methadone 30 mg daily for heroin dependency. When the dose was increased to 40 mg daily, she developed galactorrhea. Her serum prolactin levels were elevated on 3 occasions over the next year, but all other examinations were normal. Galactorrhea and amenorrhea persisted for at least 2 years with continuous methadone use. The authors of the article stated that 3 cases of hyperprolactinemia had been reported to the United Kingdom's drug regulatory agency. Causality was not proven in any of these cases.[ 63 ] A retrospective chart review of 276 opiate-dependent mothers who delivered in a Baby Friendly Hospital found that mothers taking methadone or buprenorphine for opiate dependency were unlikely to breastfeed their infants. Only 27% of the 132 mothers on methadone maintenance initiated breastfeeding. Of all women in the study, 60% discontinued breastfeeding before discharge from the hospital.[ 64 ] A retrospective cohort study of 150 women enrolled in a substance abuse treatment program found that women taki

Levels in milk

Methadone is metabolized to inactive pyrrolidine and pyrroline metabolites. In adults, methadone oral bioavailability is 80 to 95%. Maternal Levels. One mother taking 50 mg daily of oral methadone maintenance had milk sampled several times on postpartum days 4 through 8. The highest methadone breastmilk levels (100 and 120 mcg/L) were measured 4 hours after a dose. At 6 and 15 hours after a dose, the level was 40 mcg/L. Lower milk levels (20 and 30 mcg/L) were measured 0 to 3 hours after a dose.[ 23 ] Using the peak milk level from this study, an exclusively breastfed infant would receive 18 mcg/kg daily, equal to about 2% of the maternal weight-adjusted dosage. Ten mothers who were 3 to 10 days postpartum and taking oral methadone maintenance 10 to 80 mg once daily had single milk samples that contained methadone levels ranging from 50 to 570 mcg/L.[ 24 ] Using the peak level from this study, an exclusively breastfed infant would receive a maximum of 86 mcg/kg daily of methadone, equal to about 6% of the maternal weight-adjusted dosage. One mother taking 25 mg daily of oral methadone maintenance had breastmilk sampled twice on postpartum days 5 and 6. The peak methadone milk level was 700 mcg/L on day 5 and 600 mcg/L on day 6, both occurring 3 hours after the dose. Trough levels were about 15 mcg/L on both days.[ 25 ] Two postpartum mothers taking oral methadone maintenance, one 73 mg once daily and the other 30 mg twice daily, had serial milk levels sampled on day 11 and 14 postpartum, respectively. Milk levels ranged from 110 to 180 mcg/L in the first mother and 110 to 250 mcg/L in the second.[ 26 ] One lactating mother taking oral methadone maintenance 45 mg daily had milk sampled several times over the first 4 weeks postpartum and again several times over 24 hours at 6 weeks postpartum. Her colostrum methadone level was 77 mcg/L on the day of delivery and milk levels remained fairly constant (range 77 to 123 mcg/L) throughout the study period. There was little

Alternatives LactMed lists

• Butorphanol
• Fentanyl
• Hydromorphone
• Ibuprofen
• Naltrexone