Methyldopa


Description

An alpha-2 adrenergic agonist that has both central and peripheral nervous system effects. Its primary clinical use is as an antihypertensive agent. [PubChem]

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Pharmacology

Indication

For use in the treatment of hypertension.

Pharmacodynamic

Methyldopa is an aromatic-amino-acid decarboxylase inhibitor in animals and in man. Only methyldopa,... Read more

Mechanism of action

Although the mechanism of action has yet to be conclusively demonstrated, the resultant hypotensive... Read more

Absorption

Absorption from the gastrointestinal tract is variable but averages approximately 50%.

Protein binding

Low (less than 20%).

Volume of distribution

Information currently not available.

Clearance

Renal cl=130 mL/min [healthy]

Half life

The plasma half-life of methyldopa is 105 minutes.

Route of elimination

Methyldopa is extensively metabolized. The known urinary metabolites are: α-methyldopa mono-O-sulfat... Read more

Toxicity

The oral LD50 of methyldopa is greater than 1.5 g/kg in both the mouse and the rat. Sympt... Read more


Adverse Effects

Effect Regions Age Groups Incidences Evidence Type
Weakness US
Varying Reports
Asthenia US
Varying Reports
Headache US
Varying Reports
Sedation US
Varying Reports
Colitis US
Varying Reports
Pancreatitis US
Varying Reports
Bradycardia US
Varying Reports
Edema and weight gain US
Varying Reports
Orthostatic Hypotension US
Varying Reports
Prolonged carotid sinus hypersensitivity US
Varying Reports
Congestive Heart Failure US
Varying Reports
Aggravation of angina pectoris US
Varying Reports
Vasculitis US
Varying Reports
Pericarditis US
Varying Reports
Drug-related fever US
Varying Reports
Lupus-like syndrome US
Varying Reports
Positive tests for rheumatoid factor US
Varying Reports
Positive tests for LE cells US
Varying Reports
Myocarditis US
Varying Reports
Positive Coombs tests US
Varying Reports
Symptoms of cerebrovascular insufficiency US
Varying Reports
Choreoathetotic movements US
Varying Reports
Headache US
Varying Reports
Psychic disturbances US
Varying Reports
Parkinsonism US
Varying Reports
Eosinophilia US
Varying Reports
Decreased mental acuity US
Varying Reports
Bell's Palsy US
Varying Reports
Nausea US
Varying Reports
Constipation US
Varying Reports
Distension US
Varying Reports
Flatus US
Varying Reports
Vomiting US
Varying Reports
Diarrhea US
Varying Reports
Sialadenitis US
Varying Reports
Sore or ``black′′ tongue US
Varying Reports
Granulocytopenia US
Varying Reports
Thrombocytopenia US
Varying Reports
Hemolytic Anemia US
Varying Reports
Positive tests for antinuclear antibody US
Varying Reports
Dryness of mouth US
Varying Reports
Hyperprolactinemia US
Varying Reports
Bone marrow depression US
Varying Reports
Leukopenia US
Varying Reports
Rash US
Varying Reports
Toxic Epidermal Necrolysis US
Varying Reports
Breast enlargement US
Varying Reports
Amenorrhea US
Varying Reports
Lactation US
Varying Reports
Gynecomastia US
Varying Reports

Contraindications

  • Route:
    • Oral
    • Intravenous
  • Regions: US
  • With Categories Coadmin:
      • Name: Monoamine Oxidase Inhibitors
      • Drugbank Id: DBCAT001004
      • Mesh Id: D008996
  • Route:
    • Oral
    • Intravenous
  • Regions: US
  • Patient Conditions:
      • Name: Active hepatic disease
      • Drugbank Id: DBCOND0108088
      • Modification Of:
        • Condition Status: active
        • Base:
          • Name: Hepatic Disease
          • Drugbank Id: DBCOND0069929
  • Route:
    • Oral
    • Intravenous
  • Regions: US
  • Patient Conditions:
      • Name: History of liver disorders caused by methyldopa
      • Drugbank Id: DBCOND0108091
      • Combination Of:
        • Caused By:
            • Name: Methyldopa
            • Drugbank Id: DBCOND0108090
        • Included Conditions:
            • Name: History of liver disorders
            • Drugbank Id: DBCOND0108089

Food Interactions

  • Avoid alcohol.
  • Avoid natural licorice.
  • Increase dietary intake of magnesium, folate, vitamin B6, B12, and/or consider taking a multivitamin.
  • May take Vitamin D.
  • No iron, zinc or fluoride within 2 hours of taking this medication.
  • Take without regard to meals.

Interactions

Type in a drug name to check for interaction with Methyldopa

1-(3-Mercapto-2-Methyl-Propionyl)-Pyrrolidine-2-Carboxylic Acid may decrease the antihypertensive activities of Methyldopa.
1-benzylimidazole may decrease the antihypertensive activities of Methyldopa.
2,5-Dimethoxy-4-ethylamphetamine may decrease the antihypertensive activities of Methyldopa.
2,5-Dimethoxy-4-ethylthioamphetamine may decrease the antihypertensive activities of Methyldopa.
The metabolism of Methyldopa can be decreased when combined with 3,5-Dinitrocatechol.
4-Bromo-2,5-dimethoxyamphetamine may decrease the antihypertensive activities of Methyldopa.
4-Methoxyamphetamine may decrease the antihypertensive activities of Methyldopa.
5-methoxy-N,N-dimethyltryptamine may decrease the antihypertensive activities of Methyldopa.
7,8-Dichloro-1,2,3,4-tetrahydroisoquinoline may decrease the hypotensive activities of Methyldopa.
Methyldopa may decrease the excretion rate of Abacavir which could result in a higher serum level.
Abediterol may decrease the antihypertensive activities of Methyldopa.
Acarbose may decrease the excretion rate of Methyldopa which could result in a higher serum level.
The therapeutic efficacy of Methyldopa can be decreased when used in combination with Acebutolol.
The therapeutic efficacy of Methyldopa can be decreased when used in combination with Aceclofenac.
The therapeutic efficacy of Methyldopa can be decreased when used in combination with Acemetacin.
The therapeutic efficacy of Methyldopa can be decreased when used in combination with Acepromazine.
Acetaminophen may decrease the excretion rate of Methyldopa which could result in a higher serum level.
Acetazolamide may increase the excretion rate of Methyldopa which could result in a lower serum level and potentially a reduction in efficacy.
The therapeutic efficacy of Methyldopa can be decreased when used in combination with Acetylsalicylic acid.
The risk or severity of myopathy, rhabdomyolysis, and myoglobinuria can be increased when Methyldopa is combined with Acipimox.

References

  • 1 . Mah GT, Tejani AM, Musini VM: Methyldopa for primary hypertension. Cochrane Database Syst Rev. 2009 Oct 7;(4):CD003893. doi: 10.1002/14651858.CD003893.pub3. [PubMed: 19821316]
  • 2 . McCoy S, Baldwin K: Pharmacotherapeutic options for the treatment of preeclampsia. Am J Health Syst Pharm. 2009 Feb 15;66(4):337-44. doi: 10.2146/ajhp080104. [PubMed: 19202042]
  • 3 . Sica DA: Centrally acting antihypertensive agents: an update. J Clin Hypertens (Greenwich). 2007 May;9(5):399-405. [PubMed: 17485976]
  • 4 . van Zwieten PA: Development and trends in the drug treatment of essential hypertension. J Hypertens Suppl. 1992 Dec;10(7):S1-12. [PubMed: 1363322]
  • 5 . Rosenthal T, Oparil S: The effect of antihypertensive drugs on the fetus. J Hum Hypertens. 2002 May;16(5):293-8. [PubMed: 12082488]
  • 6 . van Zwieten PA, Timmermans PB: Pharmacology and characterization of central alpha-adrenoceptors involved in the effect of centrally acting antihypertensive drugs. Chest. 1983 Feb;83(2 Suppl):340-3. [PubMed: 6295709]
  • 7 . van Zwieten PA: Pharmacology of centrally acting hypotensive drugs. Br J Clin Pharmacol. 1980;10 Suppl 1:13S-20S. [PubMed: 6104975]

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