Paracetamol poisoning, also known as acetaminophen poisoning, is caused by excessive use of the medication paracetamol (acetaminophen). Most people have few or non-specific symptoms in the first 24 hours following overdose. This may include feeling tired, abdominal pain, or nausea.
Adult toxicity likely after consumption of 10-15 g.
Very few early features of toxicity but may have nausea, vomiting, shock, confusion or hepatic or renal failure.
Prothrombin Time (PT) is a good early indicator of toxicity.
Peak in aminotransferase (ALT)> 1000 U/L defines extent of damage.
Checking Paracetamol blood levels prior to 4-hours after ingestion is futile & unreliable.
1. ABC’s & Resuscitation as indicated,
2. IV access,
3. FBC, U&E’s, LFT’s, Coagulation profile as indicated
4. Paracetamol levels if >4 & <15-hours since ingestion,
5. If time of ingestion is unknown do Paracetamol level & repeat after 2-4 hours. If slope is flatter than nomogram treatment line then treat with NAC,
6. If a sustained release formula of Paracetamol has been taken obtain a second Paracetamol 4 hours after the initial one.
7. Charcoal 50g if time since ingestion <1 hour & 200 mg/kg ingested (NOT INDICATED IN CHILDREN),
8. Start N-AcetylCysteine (NAC) if:
· Presents with significant overdose (>10g) until levels are perfomed,
· Symptoms at initial presentation- until definitive levels return or
· Above treatment line on nomogram (even up to 15 hours after ingestion).
· Beware- NAC Stinks!!!
9. Give Vitamin K if INR raised,
10. If presentation is >15 hours after ingestion the nomogram is useless & treatment should be given if >10 g (or 150 mg/kg) has been ingested. Treatment may be stopped only if asymptomatic, normal LFT’s & Paracetamol levels are <70 (10MG/l),
11. If presentation is >24 hours after ingestion it is probably worth trying NAC if significant overdose has been taken.
Children <20 kgs:
· 150 mg/kg in 3 mLs/kg over 15 minutes,
· Then 50 mg/kg in 7 mLs over 4, 8 & then 8 hours.
Children >20 kg:
· 150 mg/kg in 100 mLs over 15 minutes,
· Then 50 mg/kg in 250 mLs over 4, 8 & then 8 hours.
Acetylcysteine is supplied as Parvolex 2g/10ml (200mg/ml).