Methyldopa and Hydrochlorothiazide : Uses, Side Effects, Interactions & More

Why is this medication prescribed?

The combination of methyldopa and hydrochlorothiazide is used to treat high blood pressure. Methyldopa works by relaxing the blood vessels so that blood can flow more easily through the body. Hydrochlorothiazide helps lower blood pressure by removing unnecessary water and salt from the body.

High blood pressure is a common condition and, when left untreated, it can cause damage to the brain, heart, blood vessels, kidneys, and other parts of the body. Damage to these organs can cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medications, making lifestyle changes will also help control your blood pressure. These changes include eating a diet low in fat and salt, maintaining a healthy weight, exercising for at least 30 minutes most days, not smoking, and consuming alcohol in moderation.

How should this medicine be used?

This medicine comes as a tablet to take by mouth. It is usually taken two or three times a day. To remind you to take methyldopa and hydrochlorothiazide, take them around the same time every day. Follow the directions on your prescription label carefully and ask your doctor or pharmacist to explain any parts you do not understand. Take methyldopa and hydrochlorothiazide exactly as directed. Do not take more or less, or take it more often than prescribed by your doctor.

This medicine controls high blood pressure but does not cure it. Keep taking methyldopa and hydrochlorothiazide even if you feel fine. Do not stop taking methyldopa and hydrochlorothiazide without talking to your doctor.

Other uses for this medicine

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

What special precautions should I follow?

Before taking methyldopa and hydrochlorothiazide,

  • Tell your doctor and pharmacist if you are allergic to methyldopa, hydrochlorothiazide, sulfonamides, any other medications, or any of the ingredients in methyldopa and hydrochlorothiazide tablets. Ask your doctor or pharmacist for a list of the ingredients.
  • Tell your doctor if you are taking a monoamine oxidase (MAO) inhibitor, such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate). Your doctor will probably tell you not to take methyldopa and hydrochlorothiazide.
  • Tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: cholestyramine (Prevalite), digoxin (Lanoxin), haloperidol (Haldol), levodopa (in Sinemet, in Stalevo), lithium (Lithobid), diabetes medications, prednisone (Rayos), probenecid (Probalan , in Col-Probenecid) and tolbutamide. Your doctor may need to change the doses of your medications or monitor you closely for side effects.
  • If you are taking iron supplements or vitamins that contain iron, do not take them at the same time as methyldopa and hydrochlorothiazide. Ask your doctor how long to wait after taking these supplements before taking methyldopa.
  • Tell your doctor if you have or have ever had kidney or liver disease, diabetes, gout, or high blood cholesterol.
  • Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking methyldopa and hydrochlorothiazide, call your doctor.
  • Talk to your doctor about the risks and benefits of taking methyldopa and hydrochlorothiazide if you are 65 years of age or older. Older adults generally should not take methyldopa and hydrochlorothiazide because it is not as safe as other medications that can be used to treat the same condition.
  • If you are having surgery, including dental surgery, tell your doctor or dentist that you are taking methyldopa and hydrochlorothiazide.
  • You should know that this medicine may make you drowsy. Do not drive a car or operate machinery for 48 to 72 hours after starting this drug or after increasing your dose.
  • Ask your doctor about the safe use of alcohol while taking methyldopa and hydrochlorothiazide. Alcohol can make the side effects of methyldopa and hydrochlorothiazide worse.

What special dietary instructions should I follow?

Your doctor may prescribe a low-salt or low-sodium diet. Follow these directions carefully.

What should I do if I forget a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for the one you forgot.

What side effects can this medication cause?

Methyldopa and hydrochlorothiazide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • dark urine
  • frequent urination
  • dry mouth
  • headache
  • upset stomach
  • vomiting
  • loss of appetite
  • diarrhea
  • gas
  • rash

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • extreme tiredness
  • muscle weakness or cramps
  • unexplained fever
  • yellowing of the skin or eyes
  • trouble breathing
  • swollen ankles or feet

This medicine can cause other side effects. Call your doctor if you have any unusual problems while taking this medicine.

If you experience a serious side effect, you or your doctor can submit a report online to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program ( or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

Keep this medicine in the container it came in, tightly closed, and out of the reach of children. Store at room temperature and away from excess heat and moisture (not in the bathroom).

Unnecessary medications must be disposed of in special ways to ensure that pets, children, and others cannot consume them. However, you should not flush this medicine down the toilet. Instead, the best way to dispose of your medications is through a drug take-back program. Talk to your pharmacist or contact your local garbage / recycling department to find out about take-back programs in your community. See the FDA Safe Drug Disposal website ( for more information if you do not have access to a take-back program.

It is important to keep all medicines out of the sight and reach of children, as many containers (such as those containing weekly pills and those for eye drops, creams, patches, and inhalers) are not child-resistant and small children can easily open them. To protect young children from poisoning, always close the safety caps and immediately place the medicine in a safe place, one that is upright and out of their sight and reach.

In case of emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim collapsed, had a seizure, is having trouble breathing, or is unable to wake up, immediately call 911 for emergency services.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly to determine your response to methyldopa and hydrochlorothiazide.

To relieve dry mouth caused by methyldopa and hydrochlorothiazide, chew gum or suck on sugar-free hard candy.

Do not let anyone else take your medicine. Ask your pharmacist any questions you have about refilling your prescription.

It is important that you keep a written list of all prescription and over-the-counter (over-the-counter) medications you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should take this list with you each time you visit a doctor or if you go into hospital. It is also important information to take with you in case of emergencies.

Brand Names

  • Aldoril®

Disclaimer: We have made every effort to ensure that all information is factually accurate, comprehensive and up-to-date. However, this article should not be used as a licensed health care professional’s choice of knowledge and expertise. You should always consult your doctor or other health care professional before taking any medication. The information given here is subject to change and it has not been used to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions or adverse effects. The lack of warning or other information for any drug does not indicate that the combination of medicine or medication is safe, effective or appropriate for all patients or all specific uses.

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