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.

Hydrochlorothiazide and methyldopa is a combination medicine used to treat high blood pressure (hypertension).

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

Do not use hydrochlorothiazide and methyldopa if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

You should not use this medicine if you are allergic to methyldopa or hydrochlorothiazide, or if you have:

• an allergy to sulfa drugs;
• active liver disease (including cirrhosis or hepatitis);
• a history of a liver disorder caused by taking methyldopa; or
• if you are unable to urinate.

To make sure hydrochlorothiazide and methyldopa is safe for you, tell your doctor if you have ever had:

• kidney disease (or if you are on dialysis);
• liver disease;
• pheochromocytoma (tumor of the adrenal gland);
• asthma;
• lupus;
• gout; or
• diabetes.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Hydrochlorothiazide and methyldopa can pass into breast milk and may cause side effects in the nursing baby. You should not breast-feed while using this medicine.

Hydrochlorothiazide and methyldopa is not approved for use by anyone younger than 18 years old.

Use Aldoril 25 (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• pale or yellowed skin, dark colored urine, fever, confusion or weakness;
• a light-headed feeling, like you might pass out;
• severe pain in your upper stomach spreading to your back, nausea and vomiting, fast heart rate;
• shortness of breath (even with mild exertion), swelling, rapid weight gain;
• uncontrolled muscle movements;
• unusual thoughts or behavior;
• numbness, tingling, weakness;
• chest pain;
• easy bruising, unusual bleeding;
• signs of an electrolyte imbalance--dry mouth, leg cramps, increased thirst or urination, mood changes, confusion, numbness or tingling, constipation, vomiting, bone pain, muscle pain or weakness, lack of energy, irregular heartbeats, fluttering in your chest, little or no urine; or
• severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects may include:

• abnormal liver function tests;
• headache, drowsiness, weakness;
• dizziness;
• swelling, weight gain;
• muscle or joint pain, muscle spasms; or
• stuffy nose.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Avoid becoming overheated or dehydrated during exercise, in hot weather, or by not drinking enough fluids. 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.