Chlorthalidone and Breastfeeding

Summary of use during lactation

Although amounts of chlorthalidone in milk are not great, its slow clearance may lead to accumulation in the infant, especially while nursing a newborn or preterm infant. It may also suppress lactation. An alternate drug may be preferred.

Drug levels in milk and infant serum

Maternal Levels. In 7 women taking 50 mg of oral chlorthalidone daily prior to and after delivery, milk levels 3 days after delivery (collection times unspecified) ranged from 90 to 860 mcg/L. The authors estimated that the infant would receive about 180 mcg daily of chlorthalidone from milk at this maternal dosage.[1] This would amount to about 6% of the maternal weight-adjusted dosage. 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

Chlorthalidone has been used successfully to suppress lactation by giving 200 mg orally right after delivery, followed by 100 mg daily for 3 days in conjunction with fluid restriction and breast binding.[2] However, a comparative study found no difference between chlorthalidone 200 mg daily for 7.6 days and placebo in milk leakage and breast engorgement and pain.[3] The added contribution of the diuretic to fluid restriction and breast binding, which are effective in suppressing lactation, has not been studied. There are no data on the effects of diuretics on established, ongoing lactation.

Alternative drugs to consider

Chlorothiazide, Hydrochlorothiazide

References

1. Mulley BA, Parr GD, Pau WK, et al. Placental transfer of chlorthalidone and its elimination in maternal milk. Eur J Clin Pharmacol 1978;13:129-31.658109
2. Reiher KH. Suppression of lactation by stimulation of diuresis. Zentralbl Gynakol 1963;85:188-90.13973786 PubMed
3. Vercruysse J. Inhibition of lactation. Comparative study of an estro-androgen and of a diuretic. Brux Med 1966;46:1258-66.6011090 PubMed