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Methyl-Dopa

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Methyl-Dopa, Methyldopa, Alpha Methyldopa, Aldomet

  • Safety
  1. Long safety record in pregnancy
  • Disadvantages
  1. Weak antihypertensive
  2. Less tolerated (Fatigue, Dizziness) than other agents
  • Contraindications
  1. Significant Liver Disease
  • Pharmacokinetics
  1. Renal excretion (metabolized or 63% as unchanged in urine)
  1. Start: 250 mg orally twice to three times daily
  2. Maintenance: 500 mg orally twice daily
  3. Maximum: Up to 3000 mg daily in divided doses
  1. Start: 250-500 mg IV every 6 hours (up to 1000 mg every 6 hours)
  1. Dose: 10 mg/kg/day divided bid to qid
  2. Maximum: 65 mg/kg/day up to 3000 mg/day in divided doses
  • Mechanism
  1. See Alpha Adrenergic Central Agonist
  2. See Alpha Adrenergic Receptor
  3. Central Acting Adrenergic Agonist
    1. Activates alpha-2 receptors that inhibit CNS sympathetic signals (similar to Clonidine)
    2. Results in increased parasympathetic effects and side effects
  4. Methylnorepinephrine (Methyldopa) metabolite
    1. Weak Sympathomimetic that also decreases CNS sympathetic outflow
  • Adverse Effects
  1. Somnolence
  2. Dry Mouth
  3. Orthostatic Hypotension or Dizziness
  4. Erectile Dysfunction
  5. Nightmares
  6. Involuntary movements
  7. Hepatotoxicity
  8. Sodium and water retention
    1. Reflex renin release in response to excessive Clonidine and renal hypoperfusion
    2. Discontinue for Congestive Heart Failure signs
  9. Hemolytic Anemia (rare, serious)
    1. Monitor Complete Blood Count
  • Drug Interactions
  1. Tricyclic Antidepressants
    1. Decreased Clonidine antihypertensive effect
  2. CNS Depressants (e.g. Alcohol, Benzodiazepines, Barbiturates)
    1. Increase Clonidine related CNS effects (e.g. Somnolence)
  • References
  1. Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 64-5
  2. Hamilton (2010) Tarascon Pocket Pharmacopeia, Jones and Bartlett, p. 76