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methyldopa

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Brand names: Aldomet

Central Alpha-2 Agonist Rx

Methyldopa is a medicine used to treat high blood pressure. It helps to lower your blood pressure.

What it does

Methyldopa is used to treat hypertension, which is also known as high blood pressure.

Common side effects

Sedation, Headache, Weakness

Key warnings

You should not take methyldopa if you have active liver disease like hepatitis or cirrhosis.

How It Works

Methyldopa lowers blood pressure by affecting certain chemicals in your brain. These chemicals help to relax blood vessels, which allows blood to flow more easily. This results in lower blood pressure.

How to Take It

The usual starting dose for adults is 250 mg two or three times a day for the first 2 days. Your doctor may then increase or decrease the dose every 2 days to get the best result. You can take methyldopa with or without food. Try to take it at the same times each day.

Pregnancy & Breastfeeding

Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Methyldopa can pass into breast milk. Talk to your doctor about the risks and benefits.

Missed Dose

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 continue with your regular schedule.

Storage

Store methyldopa tablets at room temperature (68° to 77°F) and protect them from light.

Side Effects (from patient reports)

Based on 5,462 FDA adverse event reports.

Baby exposed to drug during pregnancy
1,261
Baby born too early
888
Mother exposed to drug during pregnancy
794
Exposure to drug during pregnancy
654
Delivery before term
561
Baby born underweight
378
Drug not working
255
High blood pressure
255
Using drug for unapproved purpose
216
Baby not growing as expected
200

FDA Adverse Event Report Analysis

Detailed analysis of 4,692 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.

Total Reports

4,692

Death-Related Reports

217

Hospitalization Reports

1,553

Top Indication

Hypertension

Gender Distribution

Female 2,870 (74%)
Male 1,010 (26%)

Age Distribution

0–17 361
18–44 1,514
45–64 352
65–74 209
75+ 236

Most Reported Adverse Reactions (FAERS)

# Reaction Reports
1 FOETAL EXPOSURE DURING PREGNANCY 1,261
2 PREMATURE BABY 888
3 MATERNAL EXPOSURE DURING PREGNANCY 794
4 EXPOSURE DURING PREGNANCY 654
5 PREMATURE DELIVERY 561
6 LOW BIRTH WEIGHT BABY 378
7 DRUG INEFFECTIVE 255
8 HYPERTENSION 255
9 OFF LABEL USE 216
10 FOETAL GROWTH RESTRICTION 200
11 DYSPNOEA 194
12 ATRIAL SEPTAL DEFECT 189
13 PRE-ECLAMPSIA 182
14 CAESAREAN SECTION 166
15 LIVE BIRTH 165

Reactions in Death Reports

FOETAL EXPOSURE DURING PREGNANCY 61
PREMATURE BABY 34
DEATH 30
LOW BIRTH WEIGHT BABY 19
RESPIRATORY FAILURE 19
HYDROPS FOETALIS 15
CARDIAC ARREST 14
HYPERTENSION 13
PNEUMONIA 13
CARDIAC FAILURE 12

Reactions in Hospitalization Reports

MATERNAL EXPOSURE DURING PREGNANCY 316
FOETAL EXPOSURE DURING PREGNANCY 218
PREMATURE BABY 197
EXPOSURE DURING PREGNANCY 196
PREMATURE DELIVERY 183
HYPERTENSION 152
DYSPNOEA 122
DRUG INEFFECTIVE 121
LIVE BIRTH 104
PRE-ECLAMPSIA 92

Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation

Serious Warnings

You should not take methyldopa if you have active liver disease like hepatitis or cirrhosis. Also, do not take it if you have had liver problems caused by methyldopa in the past. Do not take it if you are allergic to any of the ingredients in methyldopa. You should not take this medicine if you are taking a monoamine oxidase (MAO) inhibitor.

Known Drug Interactions

Several studies demonstrate a decrease in the bioavailability of methyldopa when it is ingested with ferrous sulfate or ferrous gluconate. Coadministration of methyldopa with ferrous sulfate or ferrous gluconate is not recommended.

Mechanism: Iron supplements can prevent the body from absorbing the blood pressure medicine correctly. This means the medicine may not work well enough to control your blood pressure.

What to do: It is recommended that you do not take these two medications at the same time. Talk to your doctor about the best way to schedule your doses.

7.2 Drugs Metabolized by Catechol-O-Methyltransferase (COMT) Drugs known to be metabolized by COMT, such as isoproterenol, epinephrine, norepinephrine, dopamine, dobutamine, alpha-methyldopa, apomorphine, isoetherine, and bitolterol should be administered with caution in patients receiving entacapone regardless of the route of administration (including inhalation), as their interaction may result in increased heart rates, possibly arrhythmias, and excessive changes in blood pressure [ see Warnings and Precautions (5.10) ].

Mechanism: Both of these drugs are processed by the same enzyme in the body. Taking them together can cause the drugs to build up, which may lead to a fast heart rate or changes in blood pressure.

What to do: Use these medicines together with caution. Your doctor should monitor your heart rate and blood pressure closely during treatment.

Product Clinical Comment on Concomitant Use [See Contraindications (4.1)] ; Predominant Effect/Risk [Hypertensive Reaction (HR) [See Warnings and Precautions (5.3)] ; or Serotonin Syndrome (SS) [See Warnings and Precautions (5.7)] ] Altretamine Use with caution If not otherwise specified in this table, consider avoiding concomitant use (see also information on medication-free intervals , use agent at the lowest appropriate dose, monitor for effects of the interaction, advise the patient to report potential effects, and be prepared to discontinue the agent and treat effects of the interactio...

Mechanism: These drugs interact by changing how your body regulates chemicals that control your heart and blood vessels. This can lead to a dangerous hypertensive reaction or serotonin syndrome.

What to do: Your doctor may need to choose a different blood pressure medicine or adjust your dosages. You should report any sudden, severe headaches or vision changes to your healthcare provider immediately.

minor lithium

When methyldopa and lithium are given concomitantly, the patient should be carefully monitored for symptoms of lithium toxicity. Read the circular for lithium preparations.

Mechanism: Methyldopa can cause lithium to build up in the body to levels that are not safe.

What to do: Your doctor should monitor you closely for any signs of lithium toxicity.

No depressant effect on blood levels in humans was noted when colestipol hydrochloride was administered with any of the following drugs: aspirin, clindamycin, clofibrate, methyldopa, nicotinic acid (niacin), tolbutamide, phenytoin or warfarin.

Mechanism: This drug does not seem to change how much methyldopa gets into your blood when they are taken together.

What to do: No special changes are usually needed, but you should still monitor your health as directed by your doctor.

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Common Questions

Can I take methyldopa with other blood pressure medicines?
Yes, but your doctor may need to adjust the dose of your other medicines.
How long does it take for methyldopa to work?
It usually takes 12 to 24 hours to see a smooth blood pressure response.
What should I do if I feel lightheaded?
Lowering the dose may help. Talk to your doctor if lightheadedness continues.
Can I stop taking methyldopa suddenly?
No, stopping suddenly can cause your blood pressure to go up. Talk to your doctor before stopping.
Does methyldopa cause drowsiness?
Yes, sedation is a common side effect, especially when you first start taking it.
Can older people take methyldopa?
Yes, but they may need a lower dose due to increased sensitivity.
What is the maximum dose of methyldopa?
The maximum recommended daily dose is 3 grams.
Can methyldopa cause a dry mouth?
Yes, dry mouth is a possible side effect.
Can I take methyldopa if I have kidney problems?
Yes, but you may need a lower dose.
What do the tablets look like?
The 250 mg tablets are beige, round, and have "RA04" printed on them. The 500 mg tablets are beige, capsule-shaped, and have "RA05" printed on them.
What are the common side effects of methyldopa?
The most commonly reported side effects of methyldopa include Sedation, Headache, Weakness. Based on 5,462 FDA adverse event reports. Always consult your healthcare provider about potential side effects.
Does methyldopa interact with other medications?
Yes, methyldopa has 7 known drug interactions. Notable interactions include ferrous sulfate, carbidopa/levodopa, tranylcypromine. Always inform your doctor about all medications you are taking.
What drug class is methyldopa?
methyldopa belongs to the Central Alpha-2 Agonist drug class. It requires a prescription (Rx). Methyldopa is used to treat hypertension, which is also known as high blood pressure.
Is methyldopa safe during pregnancy?
Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. Methyldopa can pass into breast milk. Always consult your healthcare provider before using any medication during pregnancy or breastfeeding.

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What the FDA Data Shows for methyldopa

The FDA label for methyldopa (sold under brand names such as Aldomet) classifies it as a prescription-only medication in the Central Alpha-2 Agonist class. Methyldopa is used to treat hypertension, which is also known as high blood pressure. Official labeling lists 3 commonly reported side effects, including Sedation, Headache, Weakness.

Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 5,462 voluntary reports. The database also lists 7 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. Acquisition-cost data is surveyed weekly by CMS and updated as manufacturers report changes.

Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.

Data Sources

Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS).

FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.

Last updated: March 28, 2025

All federal data sources used on this page