USMLE

Norepinephrine

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Cardiovascular Drugs
  1. Beta Blockers
  2. ACE Inhibitors
  3. Angiotensin II Receptor Blockers (ARBs)
  4. Adenosine
  5. Atropine
  6. Amiodarone
  7. DHP Calcium Channel Blockers
  8. Non-DHP Calcium Channel Blockers
  9. Clonidine
  10. Clopidogrel
  11. Digoxin
  12. Dopamine
  13. Epinephrine
  14. Hydralazine
  15. Loop Diuretics
  16. Nitroglycerin
  17. Norepinephrine
  18. Spironolactone
  19. Statins
  20. Thiazide Diuretics

Summary

Norepinephrine, also known by its trade name Levophed, is a vasoconstricting drug that raises blood pressure to treat severe hypotension, especially cases of shock. The IV site must be monitored closely, as a major side effect is tissue necrosis if the IV leaks into surrounding tissue. If leakage or extravasation does occur, this tissue damage can be reversed by the drug phentolamine.

Key Points

  • Mechanism
    • Catecholamine
    • Vasoconstrictor
      • Acts on alpha-adrenergic receptors to cause peripheral vasoconstriction
      • Vasoconstriction increases vascular resistance and increases blood pressure (mean arterial pressure)
    • Mild increase in cardiac output
      • Acts on beta-adrenergic receptors to increase heart rate and contractility
    • Clinical Use
      • Hypotension (severe)
        • Shock
          • If patient is hypovolemic, fluids and/or blood must be administered prior to norepinephrine
      • Heart failure
    • Side Effects and Adverse Reactions
      • Tissue necrosis at IV site
        • Extravasation of drug around injection site causes vasoconstriction, leading to decreased perfusion
        • Can lead to local skin death around IV site
          • Monitor IV site closely
          • Infuse through a central line when possible.
          • Phentolamine can be used to reduce tissue damage if extravasation occurs
      • Myocardial ischemia
        • May result from vasoconstriction at coronary arteries
      • May cause reflex bradycardia
        • Sudden increases in blood pressure by way of vasoconstriction can lead to baroreceptor-mediated slowing of the heart
      • Dysrhythmias