(Alpha) Methyldopa

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Summary

Alpha-methyldopa is an anti-hypertensive drug that works by activating the alpha-2 receptors of the central nervous system. This leads to a decrease in sympathetic output that helps to lower blood pressure. Clinically, alpha-methyldopa is used to treat hypertension in pregnant patients. However, use of alpha-methyldopa can lead to the creation of auto-antibodies that cause autoimmune hemolysis and drug-induced lupus as side effects.

Key Points

  • Alpha-Methyldopa
    • Mechanism
      • 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
      • Hypertension in Pregnancy
        • Decreased sympathetic outflow from spinal cord, in addition to decreased effect of catecholamines on target sites
    • Adverse Effects
      • Direct Coombs-positive Hemolysis (Warm Autoimmune Hemolytic Anemia)
      • Drug-Induced Lupus
      • Sexual Impotence