Generic name: methyldopa [ meth-il-DOE-pa ]
Drug class: Antiadrenergic agents, centrally acting
Medically reviewed by Drugs.com. Last updated on Feb 6, 2023.
Uses for methyldopa
Methyldopa belongs to the general class of medicines called antihypertensives. It is used to treat high blood pressure (hypertension).
High blood pressure adds to the work load of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. High blood pressure may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.
Methyldopa works by controlling impulses along certain nerve pathways. As a result, it relaxes blood vessels so that blood passes through them more easily. This helps to lower blood pressure.
Methyldopa is available only with your doctor's prescription.
Before using methyldopa
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Although there is no specific information comparing use of methyldopa in children with use in other age groups, this medicine is not expected to cause different side effects or problems in children than it does in adults.
Dizziness or lightheadedness and drowsiness may be more likely to occur in the elderly, who are more sensitive to the effects of methyldopa.
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Iobenguane I 131
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Ferric Ammonium Citrate
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Angina (chest pain) or
- Parkinson's disease—Methyldopa may make these conditions worse
- Kidney disease or
- Liver disease—Effects of methyldopa may be increased because of slower removal from the body
- Mental depression (history of)—Methyldopa can cause mental depression
- Pheochromocytoma—Methyldopa may interfere with tests for the condition; in addition, there have been reports of increased blood pressure
- If you have taken methyldopa in the past and developed liver problems
Proper use of methyldopa
In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.
Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.
Remember that methyldopa will not cure your high blood pressure but it does help control it. Therefore, you must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life . If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.
To help you remember to take your medicine, try to get into the habit of taking it at the same time each day.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (suspension or tablets):
- For high blood pressure:
- Adults—250 milligrams (mg) to 2 grams a day. This is divided into two to four doses.
- Children—Dose is based on body weight or size and must be determined by your doctor. The usual dose is 10 mg per kilogram (kg) (4.5 mg per pound) of body weight a day. This is divided into two to four doses. Your doctor may increase the dose as needed.
- For high blood pressure:
- For injection dosage form:
- For high blood pressure:
- Adults—250 to 500 mg mixed in 100 milliliters (mL) of solution (5% dextrose) and slowly injected into a vein every six hours as needed.
- Children—Dose is based on body weight and must be determined by your doctor. The usual dose is 20 to 40 mg per kg (9.1 to 18.2 mg per pound) of body weight. This is mixed in a solution (5% dextrose) and slowly injected into a vein every six hours as needed.
- For high blood pressure:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Precautions while using methyldopa
It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.
Do not take other medicines unless they have been discussed with your doctor. This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.
If you have a fever and there seems to be no reason for it, check with your doctor. This is especially important during the first few weeks you take methyldopa, since fever may be a sign of a serious reaction to this medicine.
Before having any kind of surgery (including dental surgery) or emergency treatment, make sure the medical doctor or dentist in charge knows that you are taking this medicine.
Methyldopa may cause some people to become drowsy or less alert than they are normally. This is more likely to happen when you begin to take it or when you increase the amount of medicine you are taking. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.
Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. Getting up slowly may help, but if the problem continues or gets worse, check with your doctor.
Methyldopa may cause dryness of the mouth. For temporary relief, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.
Tell the doctor in charge that you are taking this medicine before you have any medical tests. The results of some tests may be affected by this medicine.
Side Effects of methyldopa
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Fever, shortly after starting to take this medicine
Check with your doctor as soon as possible if any of the following side effects occur:
- Swelling of feet or lower legs
- Mental depression or anxiety
- nightmares or unusually vivid dreams
- Dark or amber urine
- diarrhea or stomach cramps (severe or continuing)
- fever, chills, troubled breathing, and fast heartbeat
- general feeling of discomfort or illness or weakness
- joint pain
- pale stools
- skin rash or itching
- stomach pain (severe) with nausea and vomiting
- tiredness or weakness after having taken this medicine for several weeks (continuing)
- yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- dryness of mouth
- Decreased sexual ability or interest in sex
- dizziness or lightheadedness when getting up from a lying or sitting position
- nausea or vomiting
- numbness, tingling, pain, or weakness in hands or feet
- slow heartbeat
- stuffy nose
- swelling of breasts or unusual milk production
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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