The following groups of patients are at an increased risk of developing hepatotoxicity following a paracetamol overdose:

• patients taking liver enzyme-inducing drugs (rifampicin, phenytoin, carbamazepine, chronic alcohol excess, St John's Wort)
• malnourished patients (e.g. anorexia nervosa) or patients who have not eaten for a few days

Interestingly, acute alcohol intake, as opposed to chronic alcohol excess, is not associated with an increased risk of developing hepatotoxicity and may actually be protective.

The toxic dose of paracetamol is generally >150mg/kg

Presentation

• No symptoms
• Nausea and vomiting (most common)
• Loin pain
• Haematuria and proteinuria
• Jaundice
• Abdominal pain
• Coma
• Severe metabolic acidosis

Investigations

• Obtain following bloods:
  • FBC
  • Urea and Electrolytes
  • INR
  • Venous gas