Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 38-15 Acetaminophen + Key Features Download Section PDF Listen +++ ++ Toxic dose: 150–200 mg/kg, but not to exceed 8–10 g (acute) or > 4 g/day (chronic) Nausea, vomiting shortly after ingestion Hepatic necrosis evident after 24–48 h + Clinical Findings Download Section PDF Listen +++ ++ Nausea or vomiting shortly after ingestion Hepatic aminotransferase levels begin to increase 24–48 after ingestion; there are usually no other signs of toxicity With severe poisoning, fulminant hepatic necrosis may occur, resulting in Jaundice Hepatic encephalopathy Acute kidney injury Death Rarely, massive ingestion (eg, serum levels over 500–1000 mg/L [33–66 mmol/L]) can cause Early onset of acute coma Seizures Hypotension Metabolic acidosis + Diagnosis Download Section PDF Listen +++ ++ The diagnosis after acute overdose is based on measurement of the serum acetaminophen level Plot the serum level versus the time since ingestion on the acetaminophen nomogram shown in Figure 38–1 Ingestion of sustained-release products or coingestion of an anticholinergic agent, salicylate, or opioid drug may cause delayed elevation of serum levels which can make interpreting the nomogram difficult The nomogram is not useful after chronic or staggered overdose ++ Figure 38–1. Nomogram for prediction of acetaminophen hepatotoxicity following acute overdosage. Patients with serum levels above the line after acute overdose should receive antidotal treatment. (Adapted, with permission, from Daly FF et al. Guidelines for the management of paracetamol poisoning in Australia and New Zealand—explanation and elaboration. A consensus statement from clinical toxicologists consulting to the Australasian Poisons Information Centres. Med J Austr. 2008;188:296. © Copyright 2008 The Medical Journal of Australia. By permission from John Wiley & Sons.) Graphic Jump LocationView Full Size||Download Slide (.ppt) + Treatment Download Section PDF Listen +++ ++ Oral activated charcoal (if given within 1–2 hours of acute ingestion) Oral N-acetylcysteine (NAC), 140 mg/kg oral loading dose, followed by 70 mg/kg every 4 hours Traditional US oral regimen 72 hours (17 doses), although equivalent success has been achieved with 20–48 hours of treatment Intravenous NAC (Acetadote), 150 mg/kg administered over 60 minutes, then 50 mg/kg over 4 hours, then 100 mg/kg over 16 hour (21-hour infusion) Treatment with N-acetylcysteine is most effective if it is started within 8–10 hours after ingestion Hemodialysis is rarely indicated but might be needed in some patients with massive overdose