methyldopa (Aldomet)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

What is methyldopa-oral, and how does it work (mechanism of action)?

Methyldopa is an oral medication used to lower blood pressure. Although the exact mechanism of action is not yet understood, methyldopa is thought to lower blood pressure by activating receptors (alpha-2 receptors) in the central nervous system and by reducing the concentration of epinephrine, norepinephrine, dopamine, and serotonin. Epinephrine, norepinephrine, dopamine, and serotonin are neurotransmitters (chemicals) that nerves use to communicate. Reducing the concentration of these neurotransmitters causes blood vessels to dilate (relax or widen), and, as a result, blood pressure is reduced.

After oral administration maximum reduction in blood pressure occurs in four to six hours. When patients reach an effective dosage, a smooth blood pressure response usually occurs in 12 to 24 hours. Blood pressure usually returns to pretreatment levels 24 to 48 hours after stopping treatment because methyldopa is eliminated from the body quickly. The FDA approved methyldopa on December 20, 1962.

What brand names are available for methyldopa-oral?


Is methyldopa-oral available as a generic drug?


Do I need a prescription for methyldopa-oral?


What are the side effects of methyldopa-oral?


  • Methyldopa may cause anemia (low number of red blood cells). Before starting treatment, doctors may order certain blood tests to check blood levels of red blood cells. Additionally, periodic blood tests should be done during treatment to detect hemolytic anemia (spontaneous break-down of red blood cells). Methyldopa should be discontinued if hemolytic anemia occurs during treatment.
  • Methyldopa should be used cautiously in patients who have a history of liver disease and should be avoided in patients with active liver disease including acute hepatitis and active cirrhosis.
  • Methyldopa may cause water retention (edema or swelling of the legs) or weight gain in some patients and, therefore, should be used cautiously in heart failure patients.
  • Methyldopa is removed by certain types of dialysis procedures. In certain dialysis patients, hypertension (high blood pressure) has occurred as a result of methyldopa being removed from the body during dialysis.
  • Methyldopa should be used cautiously in patients with cerebrovascular disease because involuntary movements have been observed during treatment.

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