Methyldopa: Uses, Dosage and Side Effects

 Methyldopa: Uses, Dosage and Side Effects

What is methyldopa?

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

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

Methyldopa may also be used for purposes not listed in this medication guide.


You should not use methyldopa if you have liver disease (especially cirrhosis), or a history of liver problems caused by taking methyldopa.

Do not use 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

You should not use methyldopa if you are allergic to it, or if you have:

  • liver disease (especially cirrhosis); or

  • a history of liver problems caused by taking methyldopa.

Do not use methyldopa if you have used a 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.

Tell your doctor if you have ever had:

  • liver disease;

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

  • heart disease, angina (chest pain); or

  • a heart attack or stroke.

Tell your doctor if you are pregnant or plan to become pregnant. It is not known whether methyldopa will harm an unborn baby. However, having high blood pressure during pregnancy may cause complications such as diabetes or eclampsia (dangerously high blood pressure that can lead to medical problems in both mother and baby). The benefit of treating hypertension may outweigh any risks to the baby.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

How should I take methyldopa?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Your blood pressure will need to be checked often. Your liver function may also need to be checked.

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

Methyldopa can affect the results of certain medical tests. Tell any doctor who treats you that you are using methyldopa.

If you need surgery or a blood transfusion, tell your caregivers ahead of time that you are using methyldopa.

Methyldopa doses are based on weight in children. Your child's dose needs may change if the child gains or loses weight.

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

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

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

Overdose symptoms may include extreme drowsiness, vomiting, slow heartbeats, or fainting.

What should I avoid while taking methyldopa?

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Methyldopa side effects

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

Call your doctor at once if you have:

  • a light-headed feeling, like you might pass out;

  • pale or yellowed skin, dark colored urine, fever, confusion or weakness;

  • uncontrolled or involuntary muscle movements;

  • heart problems--swelling, rapid weight gain, feeling short of breath; or

  • signs of liver or pancreas problems--loss of appetite, upper stomach pain (that may spread to your back), nausea or vomiting, fast heart rate, dark urine, jaundice (yellowing of the skin or eyes).

Common side effects 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.

Methyldopa dosing information

Usual Adult Dose for Hypertension:

Initial dose: 250 mg orally 2-3 times a day or 250 to 500 mg IV over 30 to 60 minutes every 6 hours, up to a maximum of 3 g/day.

Maintenance dose: 500 mg to 2 g orally divided in 2 to 4 doses, up to a maximum of 3 g/day.

Usual Adult Dose for Hypertensive Emergency:

250 to 500 mg IV over 30 to 60 minutes every 6 hours up to a maximum of 1 g every 6 hours or 4 g/day. Switch to the oral route at the same dosage once blood pressure is under control.

What other drugs will affect methyldopa?

Tell your doctor about all other medicines you use, especially:

  • ferrous gluconate, ferrous sulfate, or other medicine that contains iron;

  • lithium; or

  • any other blood pressure medications.

This list is not complete. Other drugs may affect methyldopa, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Generic name: methyldopa (METH il DOE pa)
Brand name: Aldomet
Dosage form: oral tablet (250 mg; 500 mg)
Drug class: Antiadrenergic agents, centrally acting

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