TOXICOLOGY/ADDICTION MEDICINE
Beyond NAC: The Selective Role for Extracorporeal Treatments in Managing High-Risk Acetaminophen Toxicity By Robert W. Seabury, PharmD and Ana Bienvenida, PharmD
SAEM PULSE | JANUARY-FEBRUARY 2025
The Patient Case
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A 42-year-old female was found unresponsive, surrounded by several empty acetaminophen bottles. Naloxone was administered without effect, and she was emergency intubated for airway protection. Post-intubation vital signs were within normal limits, and an arterial blood gas (ABG) revealed a pH of 7.1, a PaCO2 of 27 mmHg, and a PaO2 of 400 mmHg. Laboratory results showed an acetaminophen concentration of 926 mcg/mL, an anion gap of 24 mmol/L, a CO2 of 13 mmol/L, a serum creatinine
(SCr) of 1.9 mg/dL, a lactate of 4.5 mmol/L, alanine aminotransferase (ALT) of 120 units/L, and aspartate aminotransferase (AST) of 141 units/L. N-acetylcysteine (NAC) 150 mg/kg was administered as a one-hour infusion, followed by a 250 mg/kg infusion over 21 hours. Fomepizole 15 mg/kg was given intravenously once, then 10 mg/kg every 12 hours. Despite appropriate antidotal therapy, her clinical status worsened, necessitating multiple vasopressors. Repeat laboratory values showed an acetaminophen concentration of 902 mcg/mL, an
anion gap of 36 mmol/L, a CO2 of 7 mmol/L, an SCr of 2.9 mg/dL, a lactate of 11.3 mmol/L, ALT of 215 units/L, and AST of 223 units/L.
High-Risk Acetaminophen Poisoning
High-risk acetaminophen poisonings, also known as massive acetaminophen poisonings, are typically defined as acetaminophen ingestions of at least 30 g or acetaminophen concentrations that are at least double the treatment line on the Rumack-Matthew nomogram. Though rare, high-risk poisonings