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Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006-.

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Drugs and Lactation Database (LactMed®) [Internet].

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Last Revision: February 15, 2024.

Estimated reading time: 1 minute

CASRN: 465-65-6

image 134974167 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Naloxone is excreted into milk in very small amounts and is not detectable in the plasma of breastfed infants because of its very poor oral bioavailability. Routine use of naloxone in combination products is of no concern during breastfeeding. However, if naloxone is required by the mother for an opioid overdose, she should withhold nursing until the opioid is out of her system.

Drug Levels

Maternal Levels. Four women receiving buprenorphine and naloxone combination therapy as sublingual filmstrips for opioid use disorder provided milk samples at 2.5 hours after ingestion of the drug. Three participants provided samples on Days 2, 3, 4, 14, and 30; one participant provided samples only until Day 4. Maternal buprenorphine-naloxone doses ranged from 12 mg/3 mg to 20 mg/5 mg. Naloxone was detected only on day 14 in one participant at a concentration of 1.3 mcg/L. Naloxone glucuronide was detected in only some milk samples in average concentrations ranging from 3.15 to 5.7 mcg/L. [1]

Infant Levels. Women receiving buprenorphine and naloxone combination in doses ranging from 12 mg/3 mg to 20 mg/5 mg therapy as sublingual filmstrips for opioid use disorder breastfed their infants, one exclusively and three partially. Plasma was obtained from 3 infants via a heel stick on day 14. Naloxone and naloxone glucuronide were either not detected or detected at concentrations below the limit of quantification in all infant plasma samples at day 14.[1]

Effects in Breastfed Infants

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

Effects on Lactation and Breastmilk

In contrast to its effect in some animal species, naloxone does not affect suckling-induced secretion of oxytocin or prolactin in postpartum women.[2,3]

Alternate Drugs to Consider



Jansson LM, McConnell K, Velez M, et al. Buprenorphine-naloxone maintenance and lactation. J Hum Lact 2024;40:113-9. [PubMed: 38018534]
Cholst IN, Wardlaw SL, Newman CB, Frantz AG. Prolactin response to breast stimulation in lactating women is not mediated by endogenous opioids. Am J Obstet Gynecol 1984;150:558-61. [PubMed: 6496587]
Johnson MR, Andrews MA, Seckl JR, Lightman SL. Effect of naloxone on neurohypophyseal peptide responses to breast feeding and breast stimulation in man. Clin Endocrinol (Oxf) 1990;33:81-6. [PubMed: 2401100]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Milk, Human

Narcotic Antagonists

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.

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Attribution Statement: LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Bookshelf ID: NBK501681PMID: 30000741


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