What is the rate of adverse events after oral N-acetylcysteine administered by the intravenous route to patients with suspected acetaminophen poisoning?

Ann Emerg Med. 2003 Dec;42(6):741-50. doi: 10.1016/s0196-0644(03)00508-0.


Study objective: We conduct a study to determine the rate of adverse events (anaphylactoid and cardiorespiratory) associated with the use of oral N-acetylcysteine by the intravenous route for the treatment of suspected acetaminophen poisoning and to examine specific variables that may be associated with adverse events.

Methods: We conducted a retrospective medical record review with explicit criteria. All patients who received oral N-acetylcysteine by the intravenous route from September 1995 to September 2001 were included. Patients were identified by cross-matching 3 databases. Adverse events were divided into categories of cutaneous, systemic, or life threatening. Five reviewers abstracted charts by using a standardized data collection form. Interrater reliability was calculated by using 24 medical records abstracted by all 5 reviewers.

Results: There were 7 adverse events identified in 187 patients (3.7%; 95% confidence interval 1.0% to 6.5%). Six adverse events were cutaneous and responded rapidly to antihistamines. One adverse event was life threatening but not clearly related to N-acetylcysteine. A high rate of antihistamine exposure (53%) was identified before the administration of N-acetylcysteine. Interrater agreement was higher than 95%.

Conclusion: Intravenous administration of an oral solution of N-acetylcysteine is associated with a low rate of adverse events and should be considered for selected patients with suspected acetaminophen poisoning.

MeSH terms

  • Acetaminophen / poisoning*
  • Acetylcysteine / administration & dosage*
  • Acetylcysteine / adverse effects*
  • Administration, Oral
  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anaphylaxis / epidemiology*
  • Cardiovascular Diseases / epidemiology
  • Cardiovascular Diseases / etiology
  • Child
  • Child, Preschool
  • Drug Eruptions / epidemiology
  • Drug Eruptions / etiology
  • Drug Hypersensitivity / epidemiology*
  • Drug Hypersensitivity / etiology
  • Drug Interactions
  • Drug Overdose
  • Female
  • Free Radical Scavengers / administration & dosage*
  • Free Radical Scavengers / adverse effects*
  • Histamine H1 Antagonists / therapeutic use
  • Humans
  • Indiana / epidemiology
  • Infant
  • Infusions, Intravenous
  • Male
  • Middle Aged
  • Respiratory Tract Diseases / epidemiology
  • Respiratory Tract Diseases / etiology
  • Retrospective Studies
  • Survival Analysis


  • Free Radical Scavengers
  • Histamine H1 Antagonists
  • Acetaminophen
  • Acetylcysteine