Paracetemol Overdose Flashcards
(26 cards)
How would you calculate total dose of paracetamol in the last 24 hours?
Number of tablets x mg per tablet
What is the max amount of paracetamol that should be consumed in a 24 hour period?
4g (8 tablets)
How would you calculate dose of paracetamol taken in mg/kg in 24 hours?
Total dose in 24 hours in mg/ patients weight in kg
What important conditions in the patients medical history should be carefully considered if there is suspected paracetamol overdose?
- Alcoholic liber disease
- Cystic fibrosis
- Chronic liver disease
- An eating disorder/ fasting
- Regular intake of enzyme-inducing drugs
- Significant alcohol intake
- HIV
At what stage should TOXBASE, NPIS or A&E be contacted in suspected paracetamol overdose?
- More than 75mg/kg
- Any doubt over the amount taken
- Staggered overdose >24 hours
What does NPIS stand for?
National poisons information service
Who should be called in the first instance of suspected paracetamol overdose?
Either TOXBASE or NPIS
Who should be contacted if TOXBASE or NPIS are unavailable in the instance of paracetemol overdose?
Local A&E department
What is another name for paracetemol?
Acetaminophen
What are the two different types of overdose?
- acute overdose and staggered overdose
What type of overdose is described:
Excessive ingestion over a period of <1hour in the context of self harm.
Acute overdose
What type of overdose is described:
Excessive ingestion over >1 hour in the context of treating pain, can also occur with intent of self harm.
Staggered overdose
What is a therapeutic overdose?
An overdose within the context of treating pain
What dosage of paracetemol taken in a 24 hour period would suggest serious toxicity?
> 150mg/kg
What dosage of paracetemol taken in a 24 hour period would suggest likley toxicity?
> 75mg/kg
What dosage of paracetemol taken in a 24 hour period would suggest unlikely toxicity?
<75mg/kg
What is glutathione?
It is an intrahepatic antioxidant which binds to a toxic metabolite of paracetemol which is then excreted.
How does depleted glutathione levels put a patient at higher risk from paracetemol overdose?
Puts patient at higher risk of liver injury secondary to paracetemol excess
What patients are at risk of depleted glutathione levels?
- malnourished
- psychiatric disorders
- chronic disease (HIV, CF, liver disease)
- alcohol use
What affect does long term medication that induces liver cytochrome p450 inducers/enzymes have on the risk associated with paracetemol overdose?
Presence of Cytochrome P450 inducers increases risk of liver injury secondary to paracetemol overdose
What are common medications that induce liver cytochrome p450? ,
- antiepileptics
- antibiotics
- anti-retrovirals
- St John’s wort
What are common signs of excess paracetemol overdose within the first 24 hours?
Nausea and vomiting
General abdominal pain
What are common signs of excess paracetemol overdose after 2-3 days (acute liver injury)?
- RUQ abdominal pain
- jaundice
- hepatomegaly
- loin pain
What medication is used to treat paracetemol overdose?
N-Acetylcysteine (NAC)
