Hydrochlorothiazide is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.

Hydrochlorothiazide treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or kidney disorders, or edema caused by taking steroids or estrogen. This medication is also used to treat high blood pressure (hypertension).

Hydrochlorothiazide may also be used for purposes not listed in this medication guide.

You should not use this medication if you are allergic to hydrochlorothiazide or if you are unable to urinate.

Before using this medication, tell your doctor if you have liver disease, kidney disease, glaucoma, asthma or allergies, gout, diabetes, or if you are allergic to sulfa drugs or penicillin.

Avoid drinking alcohol, which can increase some of the side effects of hydrochlorothiazide.

Avoid becoming overheated or dehydrated during exercise and in hot weather. Follow your doctor's instructions about the type and amount of liquids you should drink. In some cases, drinking too much liquid can be as unsafe as not drinking enough.

There are many other drugs that can interact with hydrochlorothiazide. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor. Keep a list of all your medicines and show it to any healthcare provider who treats you.

If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.

You should not use this medication if you are allergic to hydrochlorothiazide, or if you are unable to urinate.

To make sure you can safely take hydrochlorothiazide, tell your doctor if you have any of these other conditions:

• kidney disease;

• liver disease;

• glaucoma;

• asthma or allergies;

• gout;

• diabetes; or

• an allergy to sulfa drugs or penicillin.

FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Hydrochlorothiazide can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.