Also known as Depade, N-Cyclopropylmethylnoroxymorphone, Naltrexon, Naltrexona, Naltrexone Hydrochloride, Naltrexone.HCl, Naltrexonum, ReVia

The hydrochloride salt of naltrexone, a noroxymorphone derivative with competitive opioid antagonistic activity. Naltrexone and its metabolite 6-beta-naltrexol reverse the effects of opioids by binding to various opioid receptors in the central nervous system CNS), including the mu-, kappa- and gamma-opioid receptors; opioid effects of analgesia, euphoria, sedation, respiratory depression, miosis, bradycardia, and physical dependence are inhibited. Naltrexone is longer-acting and more potent compared to naloxone.

Originator: NCI Thesaurus | Source: The website of the National Cancer Institute (http://www.cancer.gov)

Can I take Naltrexone while breastfeeding?

Limited data indicate that naltrexone is minimally excreted into breastmilk. If naltrexone is required by the mother, it is not a reason to discontinue breastfeeding.

Drug levels

Naltrexone is used as maintenance treatment of opiate dependence in opiate-detoxified patients. Peak plasma levels of 40 to 50 mcg/L at 1 hour after the dose and average plasma levels of 3 to 5 mcg/L have been reported in adults taking daily maintenance doses. Oral bioavailability is 5 to 40% in adults. Naltrexone is metabolized to active beta-naltrexol and to other inactive metabolites.

Maternal Levels. One lactating woman who was 1.5 months postpartum and taking 50 mg of oral naltrexone daily during pregnancy and lactation had her milk sampled several times between 3.7 and 23 hours after her dose. Naltrexone milk levels were undetectable (<2 mcg/L) by 8 hours after the dose while beta-naltrexol milk levels remained detectable throughout the study period and averaged 46 mcg/L. The half-life of elimination from milk was 2.5 and 7.7 hours for naltrexone and beta-naltrexol, respectively. The authors reported that an exclusively breastfed infant would receive about 7 mcg/kg daily of naltrexone including the active metabolite, equivalent to 0.86% of the maternal weight-adjusted dosage.[1] Infant Levels. A 1.5 month-old breastfed male infant of a mother who was taking 50 mg of oral naltrexone daily during pregnancy and lactation had undetectable (<2 mcg/L) plasma levels of both naltrexone and beta-naltrexol 9.5 hours after the maternal dose, 30 minutes after starting a feeding.[1]

Effects in breastfed infants

Naltrexone is used as maintenance treatment of opiate dependence in opiate-detoxified patients. Peak plasma levels of 40 to 50 mcg/L at 1 hour after the dose and average plasma levels of 3 to 5 mcg/L have been reported in adults taking daily maintenance doses. Oral bioavailability is 5 to 40% in adults. Naltrexone is metabolized to active beta-naltrexol and to other inactive metabolites.

Maternal Levels. One lactating woman who was 1.5 months postpartum and taking 50 mg of oral naltrexone daily during pregnancy and lactation had her milk sampled several times between 3.7 and 23 hours after her dose. Naltrexone milk levels were undetectable (<2 mcg/L) by 8 hours after the dose while beta-naltrexol milk levels remained detectable throughout the study period and averaged 46 mcg/L. The half-life of elimination from milk was 2.5 and 7.7 hours for naltrexone and beta-naltrexol, respectively. The authors reported that an exclusively breastfed infant would receive about 7 mcg/kg daily of naltrexone including the active metabolite, equivalent to 0.86% of the maternal weight-adjusted dosage.[1] Infant Levels. A 1.5 month-old breastfed male infant of a mother who was taking 50 mg of oral naltrexone daily during pregnancy and lactation had undetectable (<2 mcg/L) plasma levels of both naltrexone and beta-naltrexol 9.5 hours after the maternal dose, 30 minutes after starting a feeding.[1]

Possible effects on lactation

Relevant published information was not found as of the revision date.

Alternate drugs to consider

Buprenorphine, Methadone

References

1. Chan CF, Page-Sharp M, Kristensen JH et al. Transfer of naltrexone and its metabolite 6,beta-naltrexol into human milk. J Hum Lact . 2004;20:322-6. PMID: 15296587

Last Revision Date

20130907

Disclaimer:Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

Source: LactMed – National Library of Medicine (NLM)

3D Model of the Naltrexone molecule

MolView – data visualization platform