Hydrochlorothiazide and Breastfeeding

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 in milk and infant serum

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. In a pilot study of the treatment of patients with postpartum hypertension, patients were randomized to either 12.5 mg hydrochlorothiazide plus 10 mg of lisinopril (n = 31) or 30 mg of nifedipine (n = 36) daily. The dosages could be increased to 12.5 mg hydrochlorothiazide plus 20 mg of lisinopril and then to 25 mg hydrochlorothiazide with 20 mg lisinopril. Nifedipine dosage was increased in 30 mg increments to a maximum daily dose of 120 mg daily. At discharge, 21 hydrochlorothiazide-lisinopril mothers (70%) were breastfeeding while19 nifedipine mothers (53%) were breastfeeding.[6]

Alternative drugs to consider

Chlorothiazide

References

1. Miller ME, Cohn RD, Burghart PH. Hydrochlorothiazide disposition in a mother and her breast-fed infant. J Pediatr 1982;101:789–91.7131161 PubMed
2. Stout G. Suppression of lactation. Br Med J 1962;1:1150.18117911 PubMed
3. Reisfield DR, Paret FL. Value of a diuretic in suppressing breast engorgement. J Med Soc N J 1966;63:458–61.5341754 PubMed
4. Healy M. Suppressing lactation with oral diuretics. Lancet 1961;277:1353–4. doi:10.1016/S0140-6736(61)90289-6
5. Reiher KH. Suppression of lactation by stimulation of diuresis. Zentralbl Gynakol 1963;85:188–90.13973786 PubMed
6. Fishel Bartal M, Blackwell SC, Pedroza C, et al. Oral combined hydrochlorothiazide and lisinopril vs nifedipine for postpartum hypertension: a comparative-effectiveness pilot randomized controlled trial. Am J Obstet Gynecol 2023;228:571.e1–.e10.