Can you take chlorothiazide 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.
Amounts of chlorothiazide in milk are low, but high doses might suppress lactation. Low-dose chlorothiazide appears to be acceptable during lactation. Intense diuresis with large doses may decrease breastmilk production.
Quoted from Chlorothiazide — Drugs and Lactation Database (LactMed®), National Institute of Child Health and Human Development, revised May 15, 2025.
What LactMed would consider instead
LactMed ends this record by naming the drugs it would consider in place of chlorothiazide. Whether any of them fits depends on what you are treating — this is the database’s list, not a recommendation from us.
How much chlorothiazide gets into breastmilk
Maternal Levels. After a single dose of 500 mg of chlorothiazide orally, there was no detectable drug (<1 mg/L) in the breastmilk from 11 nursing mothers at 1, 2 and 3 hours after the dose.
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
Relevant published information on chlorothiazide was not found as of the revision date. Intense diuresis with thiazides and thiazide-like diuretics, fluid restriction and breast binding have been used to suppress postpartum lactation. 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.
Frequently asked questions
Can you take chlorothiazide while breastfeeding?
Amounts of chlorothiazide in milk are low, but high doses might suppress lactation. 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 chlorothiazide while breastfeeding?
LactMed lists 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 chlorothiazide pass into breastmilk?
LactMed's measured drug levels for chlorothiazide are quoted in full on this page, under "How much gets into breastmilk".
Do I need to pump and dump after taking chlorothiazide?
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 chlorothiazide
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.