Paracetamol Overdose Flashcards
What is paracetamol overdose?
It is defined as excessive ingestion of paracetamol
What is the most common complication of paracetamol overdose?
Hepatotoxicity
What dose of paracetamol needs to be ingested before hepatotoxicity develops?
> 150mg/kg in a 24 hour period
What is the most common medication overdose of intentional self-harm?
Paracetamol
What are the four risk factors of developing paracetamol hepatotoxicity?
P450 Enzyme Inducing Drug Administration
Chronic Alcohol intake
Human Immunodeficiency Virus
Anorexia Nervosa
What four P450 enzyme inducing drugs are assoicated with paracetamol hepatotoxicity?
Rifampicin
Phenytoin
Carbamazepine
St John’s Wort
What is a protective risk factor for developing paracetamol hepatoxicity?
Acute alcohol intake
What three blood test results indicate paracetamol overdose?
Increased ALT Levels > 10,000s
Normal ALP Levels
High ALT: ALT
What are the two pharmaoclogical management options of paracetamol overdoses?
Activated Charcoal
Acetylcysteine
When is activated charchoal recommended to manage paracetamol overdose?
It is recommended in individuals who present within one hour of paracetamol overdose
How is activated charcoal used to manage paracetamol overdose?
It is used to reduce absorption of the drug
In which four circumstances is acetycysteine recommended to manage paracetamol overdose?
The plasma paracetamol concentration is on or above a single treatment line joining points of 100mg/L at 4 hours and 15mg/L at 15 hours, regardless of risk factors of hepatotoxicity
There is a staggered overdose or there is doubt over the time of paracetamol ingestion, regardless of the plasma paracetamol concentration
The patient presents within 8 – 24 hours of paracetamol overdose with ingestion of more than 150mg/kg, even if the plasma paracetamol concentration is not yet available
The patient presents after 24 hours of paracetamol overdose with jaundice or hepatic tenderness and their ALT is above the upper limit of normal
What is defined as a staggered overdose?
It is defined as the infestion of tablets over a time period of one hour
What is the most appopriate management step in cases where individuals present < 4 hrs post ingestion and don’t meet acetycysteine treatment requriements?
We dont start treatment
We repeat serum paracetamol level at 4 hours post ingestion - in cases where the level is > 100mg/L or on the nomogram line then treatment is commenced
What is the most appropriate management step in cases when the paracetamol concentration or ALT level reamin elevated despite acetycysteine infusion?
Acetylcysteine infusion should be continued
