Clinical Progress Note: Goal‐Directed N‐acetylcysteine Treatment of Acetaminophen Toxicity

Abstract

A ccording to the most recent Annual Report of the American Association of Poison Control Centers' National Poison Data System, there were 51,081 patient exposures to acetaminophen or acetaminophen-containing products treated in a healthcare facility in 2018. 1 The toxicity of acetaminophen is mediated by its metabolism into the electrophile N-acetyl-p-benzoquinone imine (NAPQI). 2 If the amount of acetaminophen ingested is higher than recommended dosages, glutathione stores may become depleted as the liver tries to detoxify NAPQI and may no longer able to keep up with the demand. As the patient progresses 24 to 36 hours after ingestion, the onset of hepatic injury becomes apparent with elevations in aspartate aminotransferase (AST). AST elevations, should they occur, are almost always present by 36 hours. 2 Maximum hepatic dysfunction, as well as elevations in prothrombin time, bilirubin, and serum creatinine, occurs 72 to 96 hours after a toxic ingestion. As a result of marked age-associated differences in the process of conjugating acetaminophen metabolites, infants and young children may be less susceptible to acetaminophen-associated hepatotoxicity, compared with their adult counterparts. 3,4 This clinical progress note addresses acetaminophen toxicity treatment, focusing on N-acetylcysteine (NAC) dosing protocols and the 2017 American College of Medical Toxicology (ACMT) position statement, Duration of Intravenous Acetylcysteine Therapy Following Acetaminophen Overdose. 5 We conducted a literature search via the PubMed database. The authors began by using the following Medical Subject Headings terms "acetaminophen overdose [title]," which yielded 299 articles, "acetaminophen hepatotoxicity [title]," which yielded 283 articles, and "acetaminophen N-acetylcysteine [title]," which yielded 335 titles. Variations of these terms were used to ensure exhaustive search results. The search results were reviewed for applicability to acetaminophen poisoning and especially goal-directed N-acetylcysteine treatment strategies.