Highlights for methyldopa
- Methyldopa oral tablet is available as a generic drug. It’s not available as a brand-name drug.
- Methyldopa comes only as a tablet you take by mouth.
- Methyldopa is used to treat hypertension (high blood pressure).
- Liver disease warning: Liver problems that can lead to death are possible when taking this drug. Never use methyldopa if you have liver disease, including acute hepatitis or active cirrhosis.
- Monoamine oxidase inhibitors warning: Don’t take methyldopa if you’re taking drugs called monoamine oxidase inhibitors (MAOIs). Examples include isocarboxazid, phenelzine, linezolid, and tranylcypromine.
- Blood disorder warning: Methyldopa may be associated with a deadly type of blood disorder called hemolytic anemia. With this condition, your red blood cells are destroyed. If it isn’t caught in time, this disorder can lead to death.
What is methyldopa?
Methyldopa is a prescription drug. It comes as an oral tablet.
Methyldopa is available in generic form only. Generic drugs usually cost less than brand-name versions.
You may take methyldopa by itself or in combination with other drugs.
Why it's used
Methyldopa is used to treat high blood pressure. Lowering your blood pressure will help reduce your risk of having a stroke or heart attack.
How it works
Methyldopa belongs to a class of drugs called centrally acting antiadrenergics. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
Your brain normally sends signals to your blood vessels that cause the vessels to narrow. This increases your blood pressure. Methyldopa prevents your brain from sending these signals. This helps to prevent your blood pressure from rising.
Methyldopa side effects
Methyldopa oral tablet may cause temporary drowsiness. This usually occurs when you first start taking the drug. It may also happen if your doctor increases your dosage.
Methyldopa can also cause other side effects.
More common side effects
The more common side effects that can occur with methyldopa include:
- lack of energy
- nausea or vomiting
- swelling of your hands or feet
- weight gain
If these effects are mild, they may disappear within a few days or a couple of weeks. If they’re more severe or don’t disappear, talk to your doctor or pharmacist.
Serious side effects
Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Heart problems. Symptoms can include:
- worsening angina (chest pain)
- swelling of your hands, feet, legs, or ankles
- weight gain
- shortness of breath
- irregular or pounding heartbeat
- Low red blood cells. Symptoms can include:
- extreme tiredness
- shortness of breath
- pale skin
- Low white blood cell levels. Symptoms can include:
- cold symptoms such as a runny nose or sore throat that don’t go away
- flu symptoms such as body aches and tiredness
- Low platelet levels. Symptoms can include:
- cuts or wounds that don’t stop bleeding
- Liver problems. Symptoms can include:
- yellowing of your skin or the whites of your eyes
- not wanting to eat
- dark-colored urine
- Allergic reactions. Symptoms can include:
- sharp chest pain
- joint pains
- trouble breathing or swallowing
- Skin problems. Symptoms can include:
- red skin
- peeling skin
- blistering skin
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
Methyldopa may interact with other medications
Methyldopa oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.
To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.
Examples of drugs that can cause interactions with methyldopa are listed below.
If you have surgery, your doctor may need to use anesthetics so you don’t feel pain. If you take methyldopa, your doctor may need to use lower doses of anesthetics. Anesthetics also lower your blood pressure. If you take methyldopa and receive regular doses of anesthetics, your blood pressure may drop too low.
Bipolar disorder drug
Using lithium with methyldopa can cause the lithium in your body to rise to dangerous levels.
Other blood pressure drugs
Taking methyldopa with any other drugs that also lower your blood pressure can increase your risk of dangerously low blood pressure. Examples of these drugs include:
- angiotensin-converting enzyme (ACE) inhibitors, such as:
- angiotensin receptor blockers (ARBs), such as:
- beta-blockers, such as:
- calcium channel blockers, such as:
- direct renin inhibitors, such as:
- loop diuretics, such as:
- potassium-sparing diuretics, such as:
- thiazide diuretics, such as:
Certain depression drugs called monoamine oxidase inhibitors (MAOIs) shouldn’t be used with methyldopa. Taking these drugs with methyldopa can cause your blood pressure to rise to dangerous levels. This is known as hypertensive crisis. It’s a medical emergency. Examples of MAOIs include:
Don’t use iron supplements if you take methyldopa. Taking iron supplements may decrease the amount of methyldopa in your body. This may make methyldopa less effective at lowering your high blood pressure.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
This drug comes with several warnings.
Methyldopa can cause a severe allergic reaction, with the following symptoms:
- trouble breathing or swallowing
- swelling of your throat or tongue
If you develop these symptoms, call 911 or go to the nearest emergency room.
Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).
Edema (swelling) warning
While you take this drug, you may have swelling in your hands and feet, or you may gain weight. You may need to take a diuretic (water pill) to help control the swelling and weight gain. If the edema gets worse or you develop heart failure, you may need to stop taking this drug.
Alcohol interaction warning
Drinking alcohol while taking methyldopa may increase the effect of this drug. It may slow your reflexes, make you sleepy, or reduce your ability to make good decisions.
Warnings for people with certain health conditions
For people with liver disease: You shouldn’t take this drug if you have or have had liver disease. Methyldopa can cause severe liver damage. Your doctor will do some tests to check how well your liver is working during the first 6 to 12 weeks after you start taking this medication.
For people with kidney disease: Methyldopa is removed from your body by your kidneys. If your kidneys aren’t working well, more of the drug may stay in your body longer and put you at risk of side effects. Talk to your doctor about any kidney problems you have or have had.
Warnings for other groups
For pregnant women: Methyldopa is a category B pregnancy drug. That means two things:
- Research in animals hasn’t shown a risk to the fetus when the mother takes the drug.
- There aren’t enough studies done in humans to show if the drug poses a risk to the fetus.
Talk to your doctor if you’re pregnant or planning to become pregnant. Animal studies don’t always predict the way humans would respond. Therefore, this drug should only be used in pregnancy if clearly needed.
For women who are breastfeeding: Methyldopa passes into breast milk. You and your doctor should talk about whether you should take methyldopa if you wish to breastfeed.
How to take methyldopa
All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:
- your age
- the condition being treated
- how severe your condition is
- other medical conditions you have
- how you react to the first dose
Dosage for hypertension (high blood pressure)
- Form: oral tablet
- Strengths: 250 mg, 500 mg
Adult dosage (ages 18–64 years)
- Typical starting dosage: 250 mg, 2–3 times per day in evenly divided doses, during the first 48 hours.
- Dosage increases: If your blood pressure is still high after 2–3 days, your doctor may increase your dosage.
- Maximum dosage: 3,000 mg per day.
Child dosage (ages 0–17 years)
- Typical starting dosage: 10 mg per kilogram of body weight per day, given in 2–4 evenly divided doses.
- Maximum dosage: 65 mg per kilogram, or 3 grams daily, whichever is less.
Senior dosage (ages 65 years and older)
Older adults may process drugs more slowly. A typical adult dosage may cause levels of the drug to be higher than normal in older people. Older adults may be more likely to faint or lose consciousness while taking this drug. You may need a lower dosage or you may need a different treatment schedule.
You may become tolerant to methyldopa between the second and third month of treatment. This means you may need more of the drug to get the same results. Your doctor may choose to either increase your dosage or add a diuretic (water pill) to help get your blood pressure back under control.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always speak with your doctor or pharmacist about dosages that are right for you.
Take as directed
Methyldopa oral tablet is used for long-term treatment. It comes with risks if you don’t take it as prescribed.
If you stop taking the drug suddenly or don’t take it at all: Your blood pressure won’t be controlled. You’ll be at higher risk of a stroke or heart attack.
If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.
If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:
- severe drop in blood pressure
- lower heart rate
- diarrhea or constipation
If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.
What to do if you miss a dose: If you forget to take your dose, take it as soon as you remember. If you remember just a few hours before the time for your next dose, only take one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.
How to tell if the drug is working: You may not feel a change, but your blood pressure should decrease. This can be seen when you measure your blood pressure with a blood pressure monitor. Your doctor will also monitor your blood pressure to make sure methyldopa is working for you.
Are there any alternatives?
There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.
Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.