USMLE

Nitroglycerin

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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

Nitroglycerin is a vasodilating drug that is used to treat chest pain, also called angina. Potential side effects include hypotension, which can be potentially life-threatening if nitroglycerin is taken along with PDE inhibitors like sildenafil. Other side effects of nitroglycerin include headache. And lastly, nitroglycerin tablets are sensitive to heat and light and should be stored in a cool, dark place.

Key Points

  • Mechanism
    • Vasodilator
      • Nitrate drug that dilates coronary arteries to increase myocardial perfusion
      • Decreases cardiac preload, afterload, and myocardial oxygen demand
        • In other words, less blood returns to the heart (preload) and less resistance for the blood leaving the heart (afterload)
      • Contraindicated in patient with increased intracranial pressure
        • The vasodilatory effects on meningeal blood vessels have the potential to increase CSF pressure
    • Clinical Use
      • Angina
        • Acute anginal attack
          • Most commonly given sublingually, either as a tablet or spray
          • Can be repeated at 5 minute intervals for a total of 3 doses in 15 minutes
            • Call 911 if angina does not resolve after first dose
        • Chronic stable angina
          • Can be administered orally or transdermally
          • Transdermal patch should be rotated sites, taken off every 12 hours, applied to arms/upper body
    • Side Effects and Adverse Reactions
      • Hypotension
        • Dizziness, faintness, syncope, weakness, flushing
          • Patient should be lying down or sitting when medication is administered
        • Contraindicated if patient is taking a phosphodiesterase inhibitors (e.g. for erectile dysfunction)
          • Have similar mechanisms and can cause severe hypotension
          • These types of medications include sildenafil (Viagra) and tadalafil (Cialis)
        • Reflex tachycardia
          • Increased heart rate in response to decreased blood pressure
        • Contraindicated in patient with hypotension
          • Check blood pressure before each dose. Do not give if systolic BP is <90
      • Headache
        • Most common side effect, expected
        • Can be treated with acetaminophen or aspirin
      • Tablets are heat and light sensitive
        • Medication should be stored in a dark, tightly closed bottle
        • Replace every 3-6 months once opened
      • Increases intraocular pressure
        • Contraindicated in closed angle glaucoma