Acetaminophen

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