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Prescription medication · Central Alpha-2 Agonist

methyldopa

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

Data updated 2026-05-15

4,692
FDA reportsLightly reported
7
InteractionsFew interactions
Rx
Availability

What the data shows

methyldopa (Aldomet) is a prescription Central Alpha-2 Agonist, among the least-reported drugs the FDA tracks (4,692 FDA reports), with 7 documented drug interactions.

Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.

methyldopa (Aldomet) is a prescription Central Alpha-2 Agonist. Methyldopa is used to treat hypertension, which is also known as high blood pressure.

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

View Alternatives → Compare with Another Drug → Full Side Effects Report →

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.

The sections below are summarized in plain English from methyldopa's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.

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.

This is a plain-language summary of methyldopa's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.

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.

This is a plain-language summary of methyldopa's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.

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.

This is a plain-language summary of methyldopa's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.

Storage

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

Side Effects (from patient reports)

Based on 4,692 FDA adverse event reports.

Most-reported reactions

Adverse reactions in FAERS for methyldopa, by number of reports

reports

What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.

Source FDA Adverse Event Reporting System (FAERS) As of 2025

Reports over time

Adverse-event reports filed for methyldopa each year to the FDA Adverse Event Reporting System (FAERS).

0100200300400500 20042007201020132016201920222025 190

Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.

Where methyldopa sits

methyldopa has more FDA adverse-event reports than 24% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.

fewest reports most reports

Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is methyldopa; the line is the median (50th percentile).

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

Reports Mentioning Death

217

4.6% of reports — not proof of cause

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
8 HYPERTENSION 255
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
16 DRUG EXPOSURE DURING PREGNANCY 148
17 PATENT DUCTUS ARTERIOSUS 145

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
LIVE BIRTH 104
PRE-ECLAMPSIA 92
BLOOD PRESSURE INCREASED 86

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...

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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This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.

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 4,692 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 4,692 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

Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.

All federal data sources used on this page