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Overview: Methyldopa is used to treat high blood pressure. It is thought to lower blood pressure by causing your blood vessels to relax and your heart rate to slow down. Common side effects include drowsiness, headache, weakness, and fluid retention. Serious side effects include liver damage and blood disorders.

Uses

What is methyldopa used for?

Methyldopa is commonly used to treat high blood pressure (hypertension).

Methyldopa may also be used for other conditions as determined by your healthcare provider.

How does methyldopa work (mechanism of action)?

Methyldopa is thought to lower blood pressure by causing your blood vessels to relax and your heart rate to slow down. Lowering blood pressure is important to prevent problems with your heart or kidneys and to decrease the risk of stroke or heart attack. 

How is methyldopa supplied (dosage forms)?

Brands and other names

  • Aldomet

Dosage forms and strengths

  • 250 mg oral tablets
  • 500 mg oral tablets

How should I store methyldopa?

Methyldopa should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of methyldopa?

The most common side effects of methyldopa are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

There may be other side effects of methyldopa that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of methyldopa?

While less common, the most serious side effects of methyldopa are described below, along with what to do if they happen.

Blood Disorders. Methyldopa can cause blood disorders, such as agranulocytosis, aplastic anemia, hemolytic anemia, low platelet levels (thrombocytopenia), and low white blood cell levels (leukopenia). Stop taking methyldopa and get help right away if you have any of the following symptoms of blood disorders.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Easy bruising or bleeding
  • Frequent infection
  • Unusual weakness or tiredness
  • Dizziness, lightheadedness, or feeling like you are about to pass out
  • Headache
  • Fast or abnormal heartbeat

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking methyldopa. Call your healthcare provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Severe Allergic Reactions. Methyldopa may cause allergic reactions, which can be serious. Stop taking methyldopa and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use methyldopa?

Allergies to Ingredients. People who are allergic to any of the following should not take methyldopa.

  • Aldomet
  • Methyldopa
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific methyldopa products they stock.

Liver Problems. Methyldopa should not be used if your liver is not working as well as it should be, or if you have had a liver problem caused by methyldopa. If there is a concern about the health of your liver, your healthcare provider may do tests to determine if it is working well enough to take this medicine.

Drug Interactions. Methyldopa should not be taken while you are using certain other medicines. Before taking methyldopa, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about methyldopa before using it?

Do not take methyldopa unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share methyldopa with other people, even if they have the same condition as you. It may harm them.

Keep methyldopa out of the reach of children.

Methyldopa can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how methyldopa affects you.

Keep all appointments with your healthcare provider for bloodwork before starting this medicine and periodically while you are taking it. This is to monitor for any blood disorders or liver damage.

What should I tell my healthcare provider before using methyldopa?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if methyldopa is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Heart disease or a history of stroke
  • Liver problems
  • Kidney problems
  • Blood disorders

Pregnancy. It is not known if or how methyldopa could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take methyldopa while you are pregnant or trying to get pregnant.

Breastfeeding. Methyldopa passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should take methyldopa while breastfeeding.

Interactions

Does methyldopa interact with foods or drinks?

There are no known interactions between methyldopa and foods or drinks.

It is unknown if drinking alcohol will affect methyldopa. The risk of dizziness may be increased if you drink alcohol while taking methyldopa. 

Does methyldopa interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking methyldopa.

  • A monoamine oxidase inhibitor (MAOI), which is a medicine usually used for depression or Parkinson’s disease
  • Any other medicine for high blood pressure
  • Lithium, which is a medicine for certain mental health conditions
  • An iron supplement

This may not be a complete list of medicines that can interact with methyldopa. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much methyldopa?

If you or someone else has used too much methyldopa, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of methyldopa?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.