N-Acetylcysteine (NAC)
Liverpool Hospital Emergency Department
∙ Indications:
Paracetamol overdose that may be associated with liver injury
Acute Single ingestion (Immediate Release)
- > 10g or > 200mg/kg (whichever is less)
- Delayed presentation of overdose (>8 hours or delay in paracetamol level result)
- Paracetamol level above the treatment nomogram
- Acute Single Ingestion (Modified Release)
- > 10g or > 200mg/kg (whichever is less)
- Delayed presentation of overdose (>4 hours or delay in paracetamol level result)
Two paracetamol levels must be reviewed in line with MJA guidelines
- Repeated supratherapeutic ingestion (nomogram is not used)
- > 10g or 200mg/kg per 24hrs
- >12g or 300mg/kg per in 48hrs
- Greater than daily therapeutic dose with GI symptoms
Formulation:
- 200mg/ml injectable (2g/10ml ampoule)
Dosage and Administration
2 bag protocol (see next page)
- 200mg/kg over 4hrs in total volume 500ml 0.9% saline or 5% glucose
- 100mg/kg over 16hrs in total volume 1L 0.9% saline or 5% glucose
May require another 16-hour bag in line with guidelines
Side Effects
Anaphylactoid reactions – (up to 50%) ->warn patients about this (less with new protocol)
- Hypotension/ flushing/ angioedema/ rash
- Treat with loratadine 10mg
- If severe – cease and restart when reaction settled
Pit Falls
- Paediatrics – same dose (mg/kg) but reduce volume of fluid –(7ml/kg)
- Errors in conversion of mg to mls please refer to policy guideline
- Incorrect use of paracetamol lab concentration levels on nomogram
- Pregnancy – Safe for use
MUST START within 8hrs of overdose (4 hours if MR) or ASAP if overdose >200mg/kg or presents
In large ingestions consider double dose NAC (2nd bag) in discussion with poisons network
Follow MJA guidelines regarding cessation