PARACETAMOL POISONING

Accidental or intentional assumption of excessive amount of paracetamol. Toxic dose: >150 mg/kg or >7.5 g (200 mg/kg for children <6 years)

Clinical features

  • First 24 hours: asymptomatic or aspecific symptoms such as nausea and vomiting, malaise, anorexia, abdominal pain
  • In patients with mild poisoning, symptoms will resolve and patient will recover. In patients with severe poisoning, symptoms will progress to the next phase
  • In 24-72 hours: progressive signs of hepatic toxicity (e.g. right upper quadrant abdominal pain, enlarged tender liver, increased transaminases)
  • After 72 hours: signs and symptoms peak at 72-96 hours and this may be followed by full recovery in 5-7 days or progression into irreversible hepatic failure (less frequently renal failure) and death

Investigations

  • Monitor liver function, renal funtion, INR
  • Rule out pregnancy (it crosses the placental barrier)

Management

  • Treatment LOC
  • Give repeated doses of activated charcoal (25-50 g every 4 hours)
  • If ingestion was <2 hours, empty the stomach to remove any remaining medicine using gastric lavage
  • Give acetylcysteine IV preferrably within 8 hours from ingestion; if patient presents later, give it anyway
    • 150 mg/kg (max 15 g) in 200 ml of Dextrose 5% in 60 minutes followed by
    • 50 mg/kg (max 5 g) in Dextrose 5% 500 ml in 4 hours followed by
    • 100 mg/kg (max 10 g) in Dextrose 5% 1000 ml in 16 hours
  • Supportive treatment

Note

  • Acetylcysteine may cause histamine release, mimicking an allergic reaction. If patient is stable, slow the infusion. If bronchospasm, stop the infusion