Paracetamol Poisoning Guidelines

Clinical Presentation and Diagnosis

Patients with paracetamol poisoning often present with nonspecific symptoms, including nausea, vomiting, and malaise, during the first 24 hours post-ingestion, and early recognition is critical as liver damage may not be apparent until 24-72 hours post-ingestion, according to the American Association for the Study of Liver Diseases 1
Right upper quadrant tenderness may be variably present in patients with paracetamol poisoning, and the absence of symptoms during the first phase does not exclude serious poisoning 1
Elevated liver enzymes, including AST and ALT, begin to rise 24-72 hours post-ingestion, potentially reaching levels >1,000 U/L or even >3,500 U/L in severe cases, as reported by the American College of Clinical Pharmacology 1, 2
Jaundice may appear 24-72 hours post-ingestion, and patients may still feel relatively well despite biochemical evidence of liver injury 1
Maximum liver damage occurs 72-96 hours post-ingestion, with AST/ALT levels potentially reaching thousands of units per liter, and coagulopathy develops, as indicated by elevated INR/prothrombin time, according to the American Association for the Study of Liver Diseases 1, 2

Very high aminotransferase levels (AST/ALT >3,500 U/L) are highly correlated with paracetamol poisoning and should raise suspicion even without clear overdose history, as stated by the American College of Medical Toxicology 2, 4
Altered mental status or hepatic encephalopathy, coagulopathy, hypoglycemia, elevated arterial lactate, and renal dysfunction are critical warning signs requiring immediate intervention, according to the American Association for the Study of Liver Diseases 1, 2, 3
Initial laboratory assessment must include serum paracetamol level, AST, ALT, alkaline phosphatase, total bilirubin, prothrombin time/INR, creatinine, blood urea nitrogen, arterial blood gas, arterial lactate, glucose, and complete blood count, as recommended by the American College of Clinical Pharmacology 1, 2

N-acetylcysteine (NAC) should be administered immediately when paracetamol poisoning is suspected, as early treatment (within 8 hours) prevents hepatotoxicity in most cases, while delayed treatment beyond 15 hours is associated with liver damage and death, according to the American Association for the Study of Liver Diseases 1, 2
Acute single ingestions exceeding 150 mg/kg or 10 grams (whichever is less) are considered potentially hepatotoxic, and severe hepatotoxicity has been documented with ingestions ranging from 10-65 grams, as reported by the American College of Medical Toxicology 4
In high-risk populations, such as chronic alcoholics, malnourished patients, and those with pre-existing liver disease, severe hepatotoxicity can occur with doses as low as 4-5 g/day, according to the European Association for the Study of the Liver 5, 4