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Paracetamol Poisoning

 

See also General Management of Acute Poisoning Guideline

This guideline is being revised.

Please contact Victorian Poisons Information Centre on 131126 for advice

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Patients Requiring Treatment (administration of charcoal)

  • Acute ingestion of 200mg/kg or more
  • Ingestion of unknown quantity
  • Ingestion of 100mg/kg or more AND recent high intake of paracetamol (multiple supratherapeutic ingestions totaling >150mg/kg in preceding 24 hours or > 90mg/kg for >1 day).

Management (see flow diagram***)

  • Activated charcoal 1g/kg immediately if less than 1 hour since potentially toxic ingestion of tablets or capsules. (Not useful for liquid ingestions as fully absorbed within 20-30 mins).
  • Serum paracetamol level at (or as soon as possible after) 4 hours post ingestion will determine the need for N- acetyl cysteine administration (see nomogram below)
  • There is nothing to be gained by measuring serum paracetamol before 4 hours
  • N-acetyl cysteine treatment should not be started unless the nomogram indicates a potentially toxic paracetamol level
  • For patients presenting more than 15 hours post ingestion, the nomogram is inaccurate. Begin treatment if toxic ingestion and continue to treat if a) symptomatic, or b) abnormal APTT or INR.
  • If N-acetyl cysteine treatment is required, do APTT/INR and baseline LFT’s upon insertion of IV.
  • N-Acetyl cysteine (see chart)
    • Loading dose 150mg/kg in N/2 saline and 5% dextrose (10mls/kg) IV over 1hr.
    • Infusion 10mg/kg/hr in N/2 Saline and 5% Dextrose (at half maintenance rate) for 20 hrs, longer if >10 hrs post ingestion or encephalopathic.
  • N-Acetyl cysteine infusion should be continued until LFTs have returned to near normal.
  • Monitor hydration and treat as indicated.

Note

  • Anaphylactoid reactions to N-Acetyl cysteine may occur (wheeze, rash): stop the infusion for 30 minutes & give promethazine (phenergan) 0.2 mg/kg i.v. then recommence infusion at half the previous rate. Increase the rate slowly over time until the desired rate is again reached.
  • For acute ingestions of slow release preparations 2 levels 4 hours apart should be done & levels should continue until they are falling. Treat if any level is over the treatment threshold on the nomogram.

Nomogram For Paracetamol Poisoning

Check you are using the correct units micromols/Litre
A level of over 1300 at 4 hours requires treatment (1000 for high risk patients)
(for acute single dose ingestions only - multiple doses over time need an individualised approach - seek advice)

nomogram-paracet.gif

N-Acetyl cysteine (NAC) infusion chart

Weight(Kg) Loading dose
NAC (mg)
In mls of N/2 saline + 5% dextrose
Give over 1 hour		 Infusion dose
NAC (mg) in
1 litre of N/2 saline +5% Dextrose		 Infusion rate
(mls per hour) for 20 hours
approx half maintenance rate
6 900mg in 60 mls 5000 12
8 1200mg in 80 mls 5300 15
10 1500mg in 100 mls 5000 20
15 2250mg in 150 mls 6000 25
20 3000mg in 200mls 6600 30
25 3750mg in 250 mls 8300 30
30 4500mg in 300 mls 8500 35
35 5250mg in 350 mls 10000 35
40 6000mg in 400 mls 10000 40
45 6750mg in 450mls 11250 40
50 7500mg in 500 mls 11100 45
55 8250mg in 500 mls 12200 45
60 9000mg in 500 mls 12000 50
Poisons flowchart
Click here to view full size pdf file (21KB)

 

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