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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: February 15, 2021.

Estimated reading time: 1 minute

CASRN: 53230-10-7

image 135004437 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Very small amounts of mefloquine are excreted in breastmilk; the amount of drug is not sufficient to harm the infant nor is the quantity sufficient to protect the child from malaria. Breastfeeding infants should receive the recommended dosages of mefloquine.[1]

Drug Levels

Maternal Levels. Two women who were 2 to 3 days postpartum were given mefloquine 250 mg orally. In one woman who provided milk samples periodically for 56 days, the milk mefloquine level declined from 53 to 32 mcg/L over this period. The average half-life in breastmilk for the 2 women was 16.6 days. The authors estimated that an exclusively breastfed infant would receive an average of 3.8% of the maternal weight-adjusted dosage of mefloquine after a single dose. However, this value could be higher with weekly doses because of accumulation.[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.

Alternate Drugs to Consider

Atovaquone and Proguanil, Doxycycline, Chloroquine


Centers for Disease Control and Prevention. CDC Yellow Book 2020: Health Information for International Travel. New York: Oxford University Press 2019. https://wwwnc​.cdc.gov​/travel/yellowbook/2020​/travel-related-infectious-diseases​/malaria.
Edstein MD, Veenendaal JR, Hyslop R. Excretion of mefloquine in human breast milk. Chemotherapy. 1988;34:165–9. [PubMed: 3262044]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Anti-infective Agents


Antiparasitic Agents

Antiprotozoal Agents

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: NBK501154PMID: 30000213


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