pharmacopeia
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/api/v1/drug/methyldopa

Mechanism of action

Sourced from openFDA

Mechanism-of-action classes: Adrenergic alpha-Agonists; Monoamine Oxidase Inhibitors.

Monoamine Oxidase

Indications

Sourced from openFDA
  • & USAGE Hypertension.ICD-10: I10

Contraindications

Sourced from openFDA
  • Methyldopa is contraindicated in patients: – with active hepatic disease, such as acute hepatitis and active cirrhosis. – with liver disorders previously associated with methyldopa therapy (see WARNINGS ).contraindicated

Dosage & administration

Sourced from openFDA

DOSAGE & ADMINISTRATION Adults : Initiation of Therapy : The usual starting dosage of methyldopa tablets is 250 mg two to three times a day in the first 48 hours. The daily dosage then may be increased or decreased, preferably at intervals of not less than 2 days, until an adequate response is achieved. To minimize the sedation, start dosage increases in the evening. By adjustment of dosage, morning hypotension may be prevented without sacrificing control of afternoon blood pressure. When methyldopa tablets are given to patients on other antihypertensives, the dose of these agents may need to be adjusted to effect a smooth transition. When methyldopa tablets are given with anti-hypertensives other than thiazides, the initial dosage of methyldopa tablets should be limited to 500 mg daily in divided doses; when methyldopa tablets are added to a thiazide, the dosage of thiazide need not be changed. Maintenance of Therapy : The usual daily dosage of methyldopa tablets is 500 mg to 2 g in two to four doses. Although occasional patients have responded to higher doses, the maximum recommended daily dosage is 3 g. Once an effective dosage range is attained, a smooth blood pressure response occurs in most patients in 12 to 24 hours. Since methyldopa has a relatively short duration of action, withdrawal is followed by return of hypertension usually within 48 hours. This is not complicated by an overshoot of blood pressure. Occasionally tolerance may occur, usually between the second and third month of therapy.

Warnings & precautions

Sourced from openFDA

It is important to recognize that a positive Coombs test, hemolytic anemia, and liver disorders may occur with methyldopa therapy. The rare occurrences of hemolytic anemia or liver disorders could lead to potentially fatal complications unless properly recognized and managed. Read this section carefully to understand these reactions. With prolonged methyldopa therapy, 10% to 20% of patients develop a positive direct Coombs test which usually occurs between 6 and 12 months of methyldopa therapy. Lowest incidence is at daily dosage of 1 g or less. This on rare occasions may be associated with hemolytic anemia, which could lead to potentially fatal complications. One cannot predict which patients with a positive direct Coombs test may develop hemolytic anemia. Prior existence or development of a positive direct Coombs test is not in itself a contraindication to use of methyldopa. If a positive Coombs test develops during methyldopa therapy, the physician should determine whether hemolytic anemia exists and whether the positive Coombs test may be a problem. For example, in addition to a positive direct Coombs test there is less often a positive indirect Coombs test which may interfere with cross matching of blood. Before treatment is started, it is desirable to do a blood count (hematocrit, hemoglobin, or red cell count) for a baseline or to establish whether there is anemia. Periodic blood counts should be done during therapy to detect hemolytic anemia. It may be useful to do a direct Coombs test before therapy and at 6 and 12 months after the start of therapy.

Adverse reactions

Sourced from openFDA

Sedation, usually transient, may occur during the initial period of therapy or whenever the dose is increased. Headache, asthenia, or weakness may be noted as early and transient symptoms. However, significant adverse effects due to methyldopa have been infrequent and this agent usually is well tolerated. The following adverse reactions have been reported and, within each category, are listed in order of decreasing severity. Cardiovascular : Aggravation of angina pectoris, congestive heart failure, prolonged carotid sinus hypersensitivity, orthostatic hypotension (decrease daily dosage), edema or weight gain, bradycardia. Digestive : Pancreatitis, colitis, vomiting, diarrhea, sialadenitis, sore or “black” tongue, nausea, constipation, distension, flatus, dryness of mouth. Endocrine : Hyperprolactinemia. Hematologic : Bone marrow depression, leukopenia, granulocytopenia, thrombocytopenia, hemolytic anemia; positive tests for antinuclear antibody, LE cells, and rheumatoid factor, positive Coombs test. Hepatic : Liver disorders including hepatitis, jaundice, abnormal liver function tests (see WARNINGS ). Hypersensitivity : Myocarditis, pericarditis, vasculitis, lupus-like syndrome, drug-related fever, eosinophilia. Nervous System/Psychiatric : Parkinsonism, Bell’s palsy, decreased mental acuity, involuntary choreoathetotic movements, symptoms of cerebrovascular insufficiency, psychic disturbances including nightmares and reversible mild psychoses or depression, headache, sedation, asthenia or weakness, dizziness, light-headedness, paresthesias. Metabolic : Rise in BUN.

Use in specific populations

Sourced from openFDA

Pregnancy Teratogenic Effects . Reproduction studies performed with methyldopa at oral doses up to 1000 mg/kg in mice, 200 mg/kg in rabbits and 100 mg/kg in rats revealed no evidence of harm to the fetus. These doses are 16.6 times, 3.3 times and 1.7 times, respectively, the maximum daily human dose when compared on the basis of body weight; 1.4 times, 1.1 times and 0.2 times, respectively, when compared on the basis of body surface area; calculations assume a patient weight of 50 kg. There are, however, no adequate and well-controlled studies in pregnant women in the first trimester of pregnancy. Because animal reproduction studies are not always predictive of human response, methyldopa should be used during pregnancy only if clearly needed. Published reports of the use of methyldopa during all trimesters indicate that if this drug is used during pregnancy the possibility of fetal harm appears remote. In five studies, three of which were controlled, involving 332 pregnant hypertensive women, treatment with methyldopa was associated with an improved fetal outcome. The majority of these women were in the third trimester when methyldopa therapy was begun. In one study, women who had begun methyldopa treatment between weeks 16 and 20 of pregnancy gave birth to infants whose average head circumference was reduced by a small amount (34.2 ± 1.7 cm vs. 34.6 ± 1.3 cm [mean ± 1 S.D.]).

Overdosage

Sourced from openFDA

Acute overdosage may produce acute hypotension with other responses attributable to brain and gastrointestinal malfunction (excessive sedation, weakness, bradycardia, dizziness, light-headedness, constipation, distention, flatus, diarrhea, nausea, vomiting). In the event of overdosage, symptomatic and supportive measures should be employed. When ingestion is recent, gastric lavage or emesis may reduce absorption. When ingestion has been earlier, infusions may be helpful to promote urinary excretion. Otherwise, management includes special attention to cardiac rate and output, blood volume, electrolyte balance, paralytic ileus, urinary function and cerebral activity. Sympathomimetic drugs [e.g., levarterenol, epinephrine, ARAMINE ®† (Metaraminol Bitartrate)] may be indicated. Methyldopa is dialyzable. The oral LD 50 of methyldopa is greater than 1.5 g/kg in both the mouse and the rat.

Approval history

Sourced from openFDA
  • Jun 29, 1984NDANDA018934Chartwell Rx
  • Apr 18, 1985ANDAANDA070076Rising

FAERS reports

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Reference statistics only. FAERS reports are voluntarily submitted and are not incidence rates, safety signals, or causal evidence. Counts reflect reporting volume — how often a reaction was reported, not how often it occurs. For decision-grade use, consult openFDA and the FAERS Public Dashboard directly.
4,754 total reports matchedLatest report Share = reports listing the reaction ÷ total matched reports. Rows can sum to >100% because a single report often lists multiple reactions.
  1. 1Foetal Exposure During Pregnancy1,29427%
  2. 2Premature Baby90319%
  3. 3Maternal Exposure During Pregnancy80017%
  4. 4Exposure During Pregnancy66314%
  5. 5Premature Delivery56312%
  6. 6Low Birth Weight Baby3798.0%
  7. 7Drug Ineffective2575.4%
  8. 8Hypertension2555.4%
  9. 9Off Label Use2204.6%
  10. 10Foetal Growth Restriction2034.3%
  11. 11Dyspnoea1944.1%
  12. 12Atrial Septal Defect1894.0%
  13. 13Pre-eclampsia1873.9%
  14. 14Caesarean Section1663.5%
  15. 15Live Birth1643.4%

Literature

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Recent PubMed references pinned to Methyldopa as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

Clinical trials

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The 10 most recently updated of 92 ClinicalTrials.gov registrations naming Methyldopa as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

Frequently asked questions

How does Methyldopa work?
Mechanism-of-action classes: Adrenergic alpha-Agonists; Monoamine Oxidase Inhibitors.
What is Methyldopa used for?
According to FDA labeling, Methyldopa carries indications including: & USAGE Hypertension.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.
What class of drug is Methyldopa?
Methyldopa is classified as Methyldopa, Adrenergic alpha-Agonists, Monoamine Oxidase Inhibitors, Decreased Blood Pressure, Decreased Central Nervous System Norepinephrine Activity.
What are the contraindications for Methyldopa?
Methyldopa labeling lists contraindications including: Methyldopa is contraindicated in patients: – with active hepatic disease, such as acute hepatitis and active cirrhosis. – with liver disorders previously associated with methyldopa therapy (see WARNINGS ).. Always consult the full prescribing information and a clinician.
Note. Data for methyldopa is illustrative MVP content compiled from public sources. pharmacopeia is for educational and informational use only and is not a substitute for professional medical advice.

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