PARACETAMOL OVERDOSE

Question 1

Max dose for adult in 24 hours

Answer 1

4g
75mg/kg/24hrs

Question 2

what is the name of the intrahepatic antioxidant which binds to a toxic metabolite of paracetamol?

Answer 2

glutathione

Question 3

patients at risk of glutathione depletion and therefore liver injury?

Answer 3

malnourished - eating disorder, cachexia
psychiatric disorders - carbamazepine
chronic disease - HIV, CF, liver disease
alcohol-use disorder

Question 4

give examples of common drugs that induce liver cytochrome p450 enzymes, therefore increasing risk of liver injury secondary to paracetamol excess

Answer 4

antiepileptics - carbamazepine, phenytoin
barbiturates - phenobarbital, primidone
antibiotics - rifampicin, rifabutin
anti-retrovirals - efavirenz, nevirapine
St Johns Wort

Question 5

common signs of excess within first 24 hours

Answer 5

nausea and vomiting
abdominal pain

Question 6

signs of acute liver injury (2-3 days)

Answer 6

RUQ abdom pain
Jaundice
hepatomegaly
reduced GCS

Question 7

criteria for pts who should be discussed/ referred to hospital for medical assessment

Answer 7

1. symptomatic
2. pt who have taken more than a licesenced daily dose AND more than 75mg/kg/24hrs
3. pt who have ingested more than licensed daily dose BUT less than 75mg/kg/24hrs on each of the preceding 2 or more days

Question 8

who is most appropriate to contact if you need advice?

Answer 8

local A+E department