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Hydrochlorothiazide and methyldopa

Generic name: hydrochlorothiazide and methyldopa [ HYE-droe-KLOR-oh-THYE-a-zide-and-METH-il-DOE-pa ]
Brand names: Aldoril 15, Aldoril 25, Aldoril D30, Aldoril D50
Dosage form: oral tablet (25 mg-250 mg)
Drug class: Antiadrenergic agents (central) with thiazides

Medically reviewed by on Aug 4, 2023. Written by Cerner Multum.

What is hydrochlorothiazide and methyldopa?

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.

Hydrochlorothiazide and methyldopa side effects

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

Hydrochlorothiazide and methyldopa may cause serious side effects. Call your doctor at once if you have:

Common side effects of hydrochlorothiazide and methyldopa may include:

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.


You should not use this medication if you have an allergy to methyldopa (Apresoline), hydrochlorothiazide, or to other sulfa drugs; if you are unable to urinate; if you have ever had a liver disease; if have had a liver disorder caused by taking methyldopa.

Do not use hydrochlorothiazide and methyldopa if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Before taking this medicine

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:

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

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.

How should I take hydrochlorothiazide and methyldopa?

Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not use hydrochlorothiazide and methyldopa in larger or smaller amounts or for longer than recommended.

Hydrochlorothiazide and methyldopa may be only part of a complete program of treatment that also includes a special diet. Follow the diet plan created for you by your doctor or nutrition counselor. Get familiar with the list of foods you should eat or avoid to help control your condition.

Your blood pressure will need to be checked often. You may also need frequent blood tests.

This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using hydrochlorothiazide and methyldopa.

You may have very low blood pressure while taking this medicine. Call your doctor if you are sick with vomiting or diarrhea, or if you are sweating more than usual. Prolonged illness can lead to a serious electrolyte imbalance, making it dangerous for you to use hydrochlorothiazide and methyldopa.

If you need surgery, tell the surgeon ahead of time that you are using hydrochlorothiazide and methyldopa. You may need to stop using the medicine for a short time.

If you are being treated for high blood pressure, keep using this medication 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.

Store at room temperature away from moisture, heat, and light.

Hydrochlorothiazide and methyldopa dosing information

Usual Adult Dose for Hypertension:

Initial doses (as determined by titration of the individual components):
-Hydrochlorothiazide 15 mg-Methyldopa 250 mg orally 2 or 3 times a day, OR
-Hydrochlorothiazide 25 mg-Methyldopa 250 mg orally twice a day, OR
-Hydrochlorothiazide 30 to 50 mg-Methyldopa 500 mg orally once a day

Maximum dose: Hydrochlorothiazide 50 mg/day

-This drug is not indicated for initial therapy. Dosage must be individualized, as determined by titration of the individual components.
-Initiate dose increases in the evening to minimize sedation.
-Tolerance to methyldopa may occur, usually between the second and third month of therapy. Additional separate doses of methyldopa or replacement of this drug with the individual components may be required.
-If this drug is given with antihypertensives other than thiazides, the initial dose of methyldopa should be limited to 500 mg a day in divided doses.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include severe weakness or drowsiness, slow heartbeats, feeling light-headed, diarrhea, or vomiting.

What should I avoid while taking hydrochlorothiazide and methyldopa?

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.

What other drugs will affect hydrochlorothiazide and methyldopa?

Taking hydrochlorothiazide and methyldopa with other drugs that make you dizzy or lower your blood pressure can worsen these effects. Ask your doctor before taking a sleeping pill, opioid pain medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.

Tell your doctor about all your current medicines and any you start or stop using, especially:

This list is not complete. Other drugs may interact with hydrochlorothiazide and methyldopa, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.