ORN Fall 2026 - Pharmacokinetics and breast milk transfer of naltrexone and extended-release buprenorphine in pregnant and lactating individuals with substance use disorders.-Handout - ORN Fall 2026

Handout - ORN Fall 2026 - Wachman

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This presentation reviewed emerging evidence on naltrexone and extended-release buprenorphine (XR buprenorphine) for pregnant and lactating individuals with substance use disorders. It emphasized that medication treatment for opioid use disorder (MOUD) in pregnancy remains standard of care, with methadone and sublingual buprenorphine traditionally used, but new data are expanding options.<br /><br />For naltrexone, the talk explained its role as an opioid receptor antagonist used for opioid and alcohol use disorders. Although pregnancy data were previously limited, newer case series, cohort studies, and a systematic review suggest reassuring outcomes: no clear increase in congenital anomalies, preterm birth, stillbirth, or neonatal mortality, and consistently lower rates of neonatal opioid withdrawal syndrome (NOWS) compared with methadone or buprenorphine. The MOM NEST study and related reports found good maternal retention, no opioid return in some participants, and no reported infant NOWS. Breast milk transfer appears low, with relative infant doses reported under 1%, suggesting compatibility with breastfeeding.<br /><br />For XR buprenorphine, the presentation described both Sublocade and CAM2038/Brixadi. Preliminary observational data and the MOMS randomized clinical trial suggest XR buprenorphine can improve maternal adherence and opioid abstinence during pregnancy without worsening infant NOWS or neurodevelopmental outcomes at 12 and 24 months. Breastfeeding studies showed low infant exposure to buprenorphine and undetectable infant plasma levels; naloxone and NMP exposures were also minimal or absent in infants.<br /><br />The speaker highlighted that lactation data for medications treating substance use disorders are still limited overall, but available evidence is reassuring. The main conclusion was that naltrexone is becoming a reasonable option for selected pregnant/postpartum patients with opioid and/or alcohol use disorder, and XR buprenorphine is an emerging option for perinatal OUD treatment, though more research is still needed.

Keywords

naltrexone

extended-release buprenorphine

pregnancy

lactation

opioid use disorder

medication treatment

neonatal opioid withdrawal syndrome

breastfeeding safety

maternal retention

perinatal substance use disorders