Methyldopa lowers blood pressure by decreasing the levels of certain chemicals in your blood. This allows your blood vessels (veins and arteries) to relax (widen) and your heart to beat more slowly and easily.

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

The combination of hydrochlorothiazide and methyldopa is used to treat high blood pressure (hypertension).

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

You should not use this medication if you are allergic to methyldopa (Apresoline) or hydrochlorothiazide, if you are unable to urinate, or if you have liver disease (including cirrhosis or hepatitis), or a history of liver problems caused by taking methyldopa.

Do not use hydrochlorothiazide and methyldopa if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

Before using hydrochlorothiazide and methyldopa, tell your doctor if you have kidney disease (or are on dialysis), angina pectoris (chest pain), glaucoma, asthma, gout, lupus, diabetes, an allergy to sulfa drugs or penicillin, or if you have ever had a stroke.

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 and methyldopa. 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.

Keep using this medicine as directed, even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

Do not use hydrochlorothiazide and methyldopa if you have used an MAO inhibitor such as furazolidone (Furoxone), isocarboxazid (Marplan), phenelzine (Nardil), rasagiline (Azilect), selegiline (Eldepryl, Emsam, Zelapar), or tranylcypromine (Parnate) in the last 14 days. A dangerous drug interaction could occur, leading to serious side effects.

You should not use this medication if you are allergic to methyldopa (Apresoline) or hydrochlorothiazide, or if you have:

• liver disease (including cirrhosis or hepatitis);

• a history of liver problems caused by taking methyldopa; or

• if you are unable to urinate.

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

• kidney disease (or if you are on dialysis);

• angina pectoris (chest pain);

• glaucoma;

• asthma;

• gout;

• lupus;

• diabetes;

• an allergy to sulfa drugs or penicillin; or

• if you have ever had a stroke.

FDA pregnancy category C. It is not known whether hydrochlorothiazide and methyldopa will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.

Hydrochlorothiazide and methyldopa 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.