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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: October 31, 2018.

Estimated reading time: 1 minute

CASRN: 58-93-5

Chemical structure

Drug Levels and Effects

Summary of Use during Lactation

Hydrochlorothiazide doses of 50 mg daily or less are acceptable during lactation. Intense diuresis with large doses may decrease breastmilk production.

Drug Levels

Maternal Levels. In a mother who was 28 days postpartum, hydrochlorothiazide reached a peak milk level of about 275 mcg/L at about 3 hours after a 50 mg oral dose. The infant received a daily dosage of about 2% of the mother's weight-adjusted dose.[1]

Infant Levels. Hydrochlorothiazide was not detectable (<20 mcg/L) in the serum of a 28-day-old breastfed infant at about 2 and 11 hours after the mother's dose.[1]

Effects in Breastfed Infants

No electrolyte abnormalities were noted in one 28-day-old infant who was breastfed since birth while his mother was taking oral hydrochlorothiazide 50 mg daily.[1]

Effects on Lactation and Breastmilk

Hydrochlorothiazide in dosages of 100 mg daily in the morning and 50 mg in the afternoon or 50 mg twice daily have been used to successfully to suppress lactation at various times postpartum.[2][3] Intense diuresis with thiazides and thiazide-like diuretics, fluid restriction and breast binding have been used to suppress postpartum lactation.[2][4][5] 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



Miller ME, Cohn RD, Burghart PH. Hydrochlorothiazide disposition in a mother and her breast-fed infant. J Pediatr. 1982;101:789-91. [PubMed: 7131161]
Stout G. Suppression of lactation. Br Med J. 1962;1:1150. Letter. PMC: PMC1958377.
Reisfield DR, Paret FL. Value of a diuretic in suppressing breast engorgement. J Med Soc N J. 1966;63:458-61. [PubMed: 5341754]
Healy M. Suppressing lactation with oral diuretics. Lancet. 1961;277:1353-4.
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
  • 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: NBK500965PMID: 30000024


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