Acetaminophen

Mechanism of Action 1

  • Central analgesic effect descending serotonergic pathways.
  • Likely component of COX inhibition (similar to NSAIDs)

Indications

  • Analgesia (see Pain ManagementPain Management
    Introduction
    Pain management can be a complex topic in anesthesia. Patient factors, like age, comorbidities, and pre-existing chronic pain can help guide analgesia during the operative period. Surg...    )

Dosage 2

  • Oral: 650 - 1000 mg PO every 4 to 6 hours. maximum daily dose should not exceed 4,000 mg (2,000-3000 mg/day for chronic alcoholics). Pediatric dosing 10-15 mg/kg PO every 4 to 6 hours. 3
  • IV: Available in some provinces in Canada. Provides 4 hours of analgesia

Complications

  • Acute overdose can cause severe hepatic damage due to accumulation of N-acetyl-p-benzoquinoneimine (NAPQI), leading to liver failure.
  • Overdose management includes activated charcoal and administration of N-acetylcysteine as an antidote.

References

  1. Shafer SL, Rathmell JP, Flood P. Stoelting’s pharmacology and physiology in anesthetic practice. Fifth edition. Philadelphia: Wolters Kluwer Health; 2015. 900 p. ↩

  2. Birdi T, Sullivan P. Ottawa anesthesia primer. Toronto, Ontario: Echo Book Publishing; 2012. ↩

  3. Coté CJ, Lerman J, Anderson BJ. A practice of anesthesia for infants and children. Seventh edition. Philadelphia, PA: Elsevier; 2024. (Coté, Lerman and Anderson’s a practice of anesthesia in infants and children). ↩