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

Losartan is an angiotensin II receptor antagonists. Losartan keeps blood vessels from narrowing, which lowers blood pressure and improves blood flow.

The combination of hydrochlorothiazide and losartan is used to treat high blood pressure (hypertension). It is also used to lower the risk of stroke in certain people with heart disease.

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

Do not use hydrochlorothiazide and losartan if you are pregnant. Stop using this medication and tell your doctor right away if you become pregnant.

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

Before using hydrochlorothiazide and losartan, tell your doctor if you have congestive heart failure, kidney or liver disease, glaucoma, asthma, low or high blood levels of potassium, gout, lupus, diabetes, or an allergy to sulfa drugs or penicillin.

This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol can further lower your blood pressure and may increase certain side effects of hydrochlorothiazide and losartan.

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.

Do not use potassium supplements or salt substitutes while you are taking hydrochlorothiazide and losartan, unless your doctor has told you to.

In rare cases, hydrochlorothiazide and losartan can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.

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

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

• kidney disease;

• liver disease;

• congestive heart failure;

• glaucoma;

• asthma;

• low or high levels of potassium in your blood;

• gout;

• lupus;

• diabetes; or

• an allergy to sulfa drugs or penicillin.

FDA pregnancy category D. Do not use hydrochlorothiazide and losartan if you are pregnant. Stop using this medication and tell your doctor right away if you become pregnant. Losartan can cause injury or death to the unborn baby if you take the medicine during your second or third trimester. Use effective birth control while taking hydrochlorothiazide and losartan.

It is not known whether hydrochlorothiazide and losartan passes into breast milk. Do not take this medication without first talking to your doctor if you are breast-feeding a baby.