Drug Levels and Effects:

Summary of Use during Lactation:

Hydrochlorothiazidedoses 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.

Hydrochlorothiazidewas 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]

Possible Effects on Lactation:

Hydrochlorothiazide100 mg daily in the morning and 50 mg in the afternoon (duration unspecified) has been used to successfully to suppress lactation at various times postpartum.[2] Intense diuresis with thiazides and thiazide-like diuretics, fluid restriction and breast binding have been used to suppress postpartum lactation.[2][3][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:



1. Miller ME, Cohn RD, Burghart PH.Hydrochlorothiazidedisposition in a mother and her breast-fed infant. J Pediatr. 1982;101:789-91. PMID:7131161
2. Stout G. Suppression of lactation. Br Med J. 1962;1:1150. Letter.
3. Healy M. Suppressing lactation with oral diuretics. Lancet. 1961;277:1353-4.
4. Reiher KH. [Suppression of lactation by stimulation of diuresis] . Zentralbl Gynakol. 1963;85:188-90. PMID:13973786

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antihypertensive Agents

  • Thiazide Diuretics

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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