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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: August 15, 2023.

Estimated reading time: 1 minute

CASRN: 58-94-6

image 134972119 in the ncbi pubchem database

Drug Levels and Effects

Summary of Use during Lactation

Low-dose chlorothiazide appears to be acceptable during lactation. Intense diuresis with large doses may decrease breastmilk production.

Drug Levels

Maternal Levels. After a single dose of 500 mg of chlorothiazide orally, there was no detectable drug (<1 mg/L) in the breastmilk from 11 nursing mothers at 1, 2 and 3 hours after the dose.[1]

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 on chlorothiazide was not found as of the revision date. Intense diuresis with thiazides and thiazide-like diuretics, fluid restriction and breast binding have been used to suppress postpartum lactation.[2-4] The added contribution of the diuretic to these measures, which are effective in suppressing lactation, has not been studied. There are no data on the effects of diuretics on established, ongoing lactation.

Alternate Drugs to Consider



Werthmann MW, Jr, Krees SV. Excretion of chlorothiazide in human breast milk. J Pediatr 1972;81:781-3. [PubMed: 5074355]
Healy M. Suppressing lactation with oral diuretics. Lancet 1961;1:1353-4. doi:10.1016/S0140-6736(61)90289-6 [CrossRef]
Stout G. Suppression of lactation. Br Med J 1962;1:1150.
Reiher KH. [Suppression of lactation by stimulation of diuresis]. Zentralbl Gynakol 1963;85:188-90. [PubMed: 13973786]

Substance Identification

Substance Name


CAS Registry Number


Drug Class

Breast Feeding


Milk, Human

Antihypertensive Agents

Thiazide Diuretics

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: NBK501520PMID: 30000580


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