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

Cover of Drugs and Lactation Database (LactMed®)

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

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Last Revision: April 20, 2020.

Estimated reading time: 1 minute

CASRN: 158966-92-8

image 135039402 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Very low levels of montelukast appear in breastmilk. Montelukast is approved for use in children as young as 6 months of age and has been used in neonates in dosages far greater than the amounts in breastmilk. Amounts ingested by the infant would not be expected to cause any adverse effects in breastfed infants. A task force respiratory experts from Europe, Australia and New Zealand found that these drugs are probably safe during breastfeeding.[1] No special precautions are required.

Drug Levels

Maternal Levels. Seven women were given a 10 mg dose of montelukast and provide milk samples before the dose and at 6 times over the next 12 hours. Average peak milk concentration of the drug were 9.74 mcg/L at an average of 4 hours after the dose. The average milk concentration was 5.3 mcg/L which resulted in an average daily infant dosage of 0.79 mcg/kg (range 0.4 to 1.4 mcg/kg daily) or 0.68% of the weight-adjusted maternal dosage.[2]

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

Effects in Breastfed Infants

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

Effects on Lactation and Breastmilk

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


Middleton PG, Gade EJ, Aguilera C, et al. ERS/TSANZ Task Force Statement on the management of reproduction and pregnancy in women with airways diseases. Eur Respir J. 2020;55:1901208. [PubMed: 31699837]
Datta P, Rewers-Felkins K, Baker T, et al. Transfer of montelukast into human milk during lactation. Breastfeed Med. 2017;12:54–7. [PubMed: 28002678]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Anti-Asthmatic Agents

Leukotriene 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.

Copyright Notice

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

Bookshelf ID: NBK501488PMID: 30000548


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