Hydrochlorothiazide and Breastfeeding

Breastfeeding is a natural and nutritionally beneficial way of feeding a baby. However, caution must be used when taking medications while breastfeeding, whether they be prescription, over-the-counter or homeopathic medications. Certain amounts of the medication you take can be passed to your baby through breast milk, which may not be safe for the baby. Hydrochlorothiazide is a medication used as a diuretic or anti-hypertensive that is only available by prescription.


The National Institutes of Health (NIH) identifies hydrochlorothiazide is a prescription medication that falls into the category of diuretics, meaning it is used to treat fluid retention or high blood pressure. Such diuretics may be referred to as water pills. The medication removes excess fluid from the body, which then is excreted through urine. Hydrochlorothiazide use requires close monitoring, and the NIH recommends keeping all appointments with your doctor for checkups and laboratory work.

Side Effects

Frequent urination is the most common side effect of taking hydrochlorothiazide, although this should decrease or go away after taking the medication regularly for a few weeks, the NIH explains. Other side effects include muscle weakness, dizziness, cramps, thirst, stomach pain, nausea, vomiting, diarrhea, loss of appetite, headache and hair loss. If these symptoms remain after a few weeks, or are severe at any time, contact your doctor. The following side effects require contacting your physician immediately: sore throat with fever, unusual bleeding or bruising, severe skin rash with peeling skin and difficulty breathing or swallowing.

Medications and Breastfeeding

Drugs that are safe during pregnancy may not be safe during breastfeeding, and vice versa. The American Academy of Family Physicians (AAFP) explains that the benefits of the medication for the mother must be weighed against the potential risk of exposing the infant to that medication. The safety of medications while breastfeeding is dependent upon the concentration of the medication that is transferred to the infant through breast milk and the amount of breast milk the infant drinks. There are few high-quality research studies about specific medications and lactation.

Hydrochlorothiazide in Breast Milk

The AAFP identifies diuretics, specifically hydrochlorothiazide, as being safe for breastfeeding women, with precaution. Hydrochlorothiazide when taken in low doses, 25 milligrams or less per day, are passed in very low concentrations into breast milk and do not inhibit lactation, making the drug compatible with nursing.


The AAFP recommends nursing the infant just before the medication dose is due to decrease the concentration of medication that is transferred to the infant. Taking the medication right before the infant's longest interval of sleep will further decrease the amount of drug transferred to the infant. Always consult your physician and pediatrician before taking any medication to verify its safety during breastfeeding and dose in breast milk.