Drug Levels and Effects:

Summary of Use during Lactation:

Spironolactone appears acceptable to use during breastfeeding.

Drug Levels:

Maternal Levels.

The major metabolite of spironolactone, canrenone, was measured in the serum and milk of a 17-day postpartum woman who was taking 25 mg of spironolactone four times daily. Milk canrenone levels 2 hours after the dose were 104 mcg/L, and 47 mcg/L at 14.5 hours after the dose. The authors estimated that the nursing infant would receive about 0.2% of the mother's total daily dosage in the form of canrenone.[1] Active sulfur-containing metabolites were not measured.

Infant Levels.

Relevant published information was not found as of the revision date.

Effects in Breastfed Infants:

In 17-day-old breastfed (extent not stated) infant whose mother was taking 25 mg of spironolactone 4 times daily since pregnancy, serumsodiumandpotassiumremained normal.[1]

Spironolactone 75 mg every other day was taken orally by a mother while nursing a newborn. She was also taking 400 mg of bretylium tosylate every 8 hours, atenolol 25 mg daily, propranolol 20 mg 3 times a day, and multivitamin,potassiumand magnesium supplements. Jaundice, thought to be unrelated to the drug, occurred at 60 hours of age, but resolved. The infant had appropriate weight gain and development during the first 4 months of life.[2]

Possible Effects on Lactation:

Intense diuresis can suppress lactation;[3][4] however, it is unlikely that spironolactone alone is sufficiently potent to cause this effect.


1. Phelps DL, Karim A. Spironolactone: relationship between concentrations of dethioacetylated metabolite in human serum and milk. J Pharm Sci. 1977;66:1203. PMID:894512
2. Gutgesell M, Overholt E, Boyle R. Oral bretylium tosylate use during pregnancy and subsequent breastfeeding: a case report. Am J Perinatol. 1990;7:144-5. PMID:2331276
3. Healy M. Suppressing lactation with oral diuretics. Lancet. 1961;1:1353-4.
4. Cominos DC, Van Der Walt A, Van Rooyen AJ. Suppression of postpartum lactation with furosemide. S Afr Med J. 1976;50:251-2. PMID:3858

Substance Identification:

Substance Name:


CAS Registry Number:


Drug Class:

  • Antihypertensive Agents

  • Diuretics

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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