Medicine & USMLE


Sympathomimetics and Sympatholytics (New)
  1. Isoproterenol
  2. Dobutamine
  3. Norepinephrine
  4. Alpha-Methyldopa
  5. Midodrine
  6. Clonidine & Guanfacine
  7. Phenylephrine


Alpha-methyldopa is a sympatholytic drug that suppresses the activity of the sympathetic nervous system.
It does this by acting as an alpha-2 agonist. Clinically, alpha-methyldopa is most commonly used to treat hypertension during pregnancy. Side effects include drug-induced lupus, hyperprolactinemia, and direct Coombs-positive hemolysis.

Key Points

  • Alpha-Methyldopa
    • Mechanism
      • Sympatholytic
        • Suppresses fight or flight response
      • Alpha-2 Agonist
        • In brainstem: leads to reduced sympathetic outflow from spinal cord
        • On presynaptic neurons: leads to negative feedback and decreased release of catecholamines on target sites (heart, smooth muscle)
    • Clinical Use
      • Treats Hypertension in Pregnancy
        • Decreased sympathetic outflow from spinal cord, in addition to decreased effect of catecholamines on target sites
    • Side Effects
      • Direct Coombs-positive Hemolysis
        • Also known as Warm Autoimmune Hemolytic Anemia
      • Drug-Induced Lupus
      • Hyperprolactinemia