USMLE

Acetaminophen

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Musculoskeletal Drugs
  1. Azathioprine
  2. Corticosteroids
  3. Sulfasalazine
  4. TNF Inhibitors
  5. Immunosuppressants (Cyclosporine, Mycophenolate, Tacrolimus)
  6. Acetaminophen
  7. NSAIDs
  8. Colchicine
  9. Allopurinol
  10. Rasburicase
  11. Dantrolene
  12. Muscle Relaxants
  13. Bisphosphonates: Alendronate, Risedronate

Summary

Acetaminophen, commonly known by its trade name Tylenol, is a medication used to treat pain and reduce fever. Its most important side effect is hepatotoxicity, which can be prevented by limiting the dose of acetaminophen given to under 4 grams per day. In the case of an overdose, acetylcysteine can be given as an antidote to minimize liver damage.

Key Points

  • Mechanism
    • Analgesic
      • Weak inhibition of prostaglandin synthesis in the central nervous system
    • Antipyretic
      • Inhibition of hypothalamic heat-regulator center
    • Note that acetaminophen is not an NSAID and does not have anti-inflammatory properties
    • Clinical Use
      • Pain reliever (analgesic)
      • Treats fever
    • Side Effects and Adverse Reactions
      • Hepatotoxicity
        • Black box warning
        • Big concern if acetaminophen is ingested in large doses / overdose over a short period of time
        • Do not exceed 4 grams per day
          • When calculating total, be sure to include all medications that contain acetaminophen, including cold medications (e.g. Dayquil), and narcotic combinations (e.g. Percocet)
        • Early symptoms include nausea, vomiting, diarrhea, and abdominal pain
      • Nephrotoxicity
        • Concern if acetaminophen is ingested in large doses over a long period of time
    • Antidote
      • Acetylcysteine