Paracetamol Poisoning

Clinical Description

• Paracetamol is an ingredient of many over the counter pain, cold, and flu remedies
• A dose of over 150 mg/kg (i.e. approx. 10 g in an adult) may cause severe liver and (less frequently) kidney damage within hours of ingestion
• In the first 24 hours there may be nausea and vomiting or there may be no sign of poisoning
• Persistence of these symptoms and associated right subcostal pain and tenderness usually indicates hepatic necrosis
• Liver damage reaches a maximum 3-4 days after poisoning and may be fatal

If overdose occurs within 4 hours of admission:

• Empty the stomach to remove ingested medicine
• If respiration is depressed: do not use emesis - use airway protected gastric lavage instead
• Keep patient warm and quiet
• Observe carefully for at least 3-4 days
• Monitor fluid, electrolytes, blood glucose, liver and kidney function
• Give supportive care and correct fluid and electrolyte balance as required

Even if there are no significant early symptoms, overdose patients should be urgently transferred to hospital

Adults

If within 24 hours of overdose with over 10g of paracetamol:

• Give the specific antidote N-acetylcysteine as an IV infusion in Glucose 5%
• Initially give 150mg/kg in 200ml over 15 minutes
• Then give 50 mg/kg in 500 ml over 4 hours
• Then give 100mg/kg in 1L over 16 hours

If a serious reaction occurs:

• Stop the infusion
• Treat the reaction (see Section 5.1.1)
• Restart the infusion

Children

Treatment is usually guided by Paracetamol levels

If these are unavailable, use the empiric Acetylcysteine regime

Weight Initial dose Second dose Third dose Instructions <20 kg 150 mg/kg in 3 ml/kg fluid over 1 hour 50 mg/kg in 7 ml/kg over 4 hours 100 mg/kg in 14 ml/kg over 16 hours

Mix in 5% Dextrose or 0.9% sodium chloride 20-40 kg 150 mg/kg in 100 ml fluid over 1 hour 50 mg/kg in 250 ml over 4 hours 100 ml/kg in 500 ml over 16 hours

Mix in 5% Dextrose or 0.9% sodium chloride >40 kg 150 mg/kg in 200 ml fluid over 1 hour 50 mg/kg in 500 ml over 4 hours 100 ml/kg in 1 litre over 16 hours

Mix in 5% Dextrose or 0.9% sodium chloride

Anaphylaxis to Acetylcysteine should be managed in accordance with standard treatment protocols, but the infusion should be continued at a slower rate.

If Acetylcysteine is not available, then PO Methionine can be used:

• < 20 kg 625 mg
• 20 – 40 kg 1.25 grams
• >40 kg 2.5 grams