Can you take chlorthalidone while breastfeeding?
What LactMed says
The National Library of Medicine’s own summary, quoted in full. We do not write a verdict of our own on this question, and we do not compress theirs into a label.
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.
Quoted from Chlorthalidone — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised July 15, 2026.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of chlorthalidone. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much chlorthalidone gets into breastmilk
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. 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.
What has been seen in breastfed infants
Relevant published information was not found as of the revision date.
Effects on milk supply
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. 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. 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.
Frequently asked questions
Can you take chlorthalidone while breastfeeding?
What the NIH's Drugs and Lactation Database says about Chlorthalidone while breastfeeding — quoted in full. The full record is quoted on this page, and the decision is one to make with the person who prescribed it — LactMed itself states it is not a substitute for professional judgement.
What can I take instead of chlorthalidone while breastfeeding?
LactMed lists Chlorothiazide, Hydrochlorothiazide as alternate drugs to consider. That is the database's own list for this drug — whether any of them suits you depends on what you are treating.
Does chlorthalidone pass into breastmilk?
LactMed's measured drug levels for chlorthalidone are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking chlorthalidone?
LactMed does not frame its records that way — it reports measured drug levels in milk and what has been observed in breastfed infants, which is what this page quotes. "Pump and dump" advice for a specific drug and dose should come from your clinician or a pharmacist, not from a general rule.
More on chlorthalidone
LactMed states that the information it presents is not a substitute for professional judgement, and that you should consult your healthcare provider for breastfeeding advice related to your particular situation. Nothing on this page is medical advice.