N-Acetylcysteine

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General

  • Type:
  • Dosage Forms:
  • Common Trade Names:

Adult Dosing

Pediatric Dosing

Special Populations

  • Pregnancy Rating:
  • Lactation:
  • Renal Dosing
    • Adult
    • Pediatric
  • Hepatic Dosing
    • Adult
    • Pediatric

Contraindications

  • Allergy to class/drug

Adverse Reactions

Serious

Common

Pharmacology

  • Half-life:
  • Metabolism:
  • Excretion:
  • Mechanism of Action:

See Also

Sources


  • Also known as NAC
  • Intravenous acetylcysteine is indicated for the treatment of acetaminophen overdose by preventing depletion of glutathione reserves.
  • Both IV or oral NAC may be used in pregnant patients with Acetaminophen toxicity. [1]
    • IV formulation may be preferred to increase fetal NAC concentrations

N-acetylcysteine (NAC)

Background

  1. Almost 100% effective if given <8 hr post-ingestion; less effective if 16-24 hr post-ingestion
  2. May still be useful >24 hr post-ingestion, even with fulminant hepatic failure. Give NAC until LFTs improve (not until APAP level is 0) [2] [3]
  3. Be aware NAC treatment may affect PT. May see a dose-dependent increase in PT following NAC in patients without hepatotoxicity. [4]

Dosing:

PO

  1. 140mg/kg PO load
  2. 70mg/kg PO q4hr x17 doses additional; dilute to 5% soln
Side Effects
sulfur-smell causes nausea and vomiting. Consider mixing with juice or soda, in a cup with a lid and straw

IV

  1. Loading dose: 150mg/kg in 100 mL D5W over 60min
  2. Second (maintenance) dose: 50mg/kg in 250 mL D5W over 4hr
  3. Third dose: 100mg/kg in 500 mL D5W over 16hr
Side Effects
  1. Anaphylactoid reaction but also associated with seizures, cerebral edema, & herniation. [5]
  2. Anaphylaxis responds to standard therapies and can usually restart NAC without safely without complications. [6]

See Also

  1. Heard KJ. Acetylcysteine for acetaminophen poisoning. N Eng J Med. 2008;359(3):285-292. (Review)
  2. Keays R, Harrison PM, Wendon JA, et al. Intravenous acetylcysteine in paracetamol-induced fulminant hepatic failure: a prospective controlled trial. BMJ. 1991;303(6809):1026-1029. (Prospective randomized controlled trial; 50 patients)
  3. Harrison PM, Keays R, Bray GP, et al. Improved outcome of paracetamol-induced fulminant hepatic failure by late administration of N-acetylcysteine. Lancet. 1990;335(8705):1572- 1573. (Retrospective analysis; 100 patients)
  4. Wasserman GS, Garg U. Intravenous administration of Nacetylcysteine: interference with coagulopathy testing. Ann Emerg Med. 2004;44(5):546-547. (Letter)
  5. http://journals.lww.com/em-news/Fulltext/2012/02000/Toxicology_Rounds__Lessons_from_the_Courtroom_.9.aspx
  6. Sandilands EA, Bateman DN. Adverse reactions associated with acetylcysteine. Clin Toxicol (Phila). 2009;47(2):81-88. (Systematic literature review)