Paracetamol overdose

Question 1

Define

Answer 1

• Excessive ingestion of paracetamol causing toxicity

• MAX recommended dose: 4g in 24 hrs
• Intake > 12 g can cause hepatic necrosis

Question 2

What are the risk factors?

Answer 2

o Chronic alcohol abusers
o Patients on enzyme-inducing drugs (e.g. anticonvulsants)
o Malnourished
o Anorexia nervosa
o HIV
o Paracetamol overdose is commonly associated with ingestion of large amounts of alcohol

Question 3

Epidemiology

Answer 3

• Most COMMON intentional drug overdose in the UK

* Causes 100 deaths/yr in the UK

Question 4

What are the presenting symptoms?

Answer 4

•	Make sure you ascertain the TIMING and QUANTITY of overdose and presence of risk factors 
•	0-24 hrs 
o	ASYMPTOMATIC
o	Mild nausea/vomiting 
o	Lethargy 
o	Malaise 
•	24-72 hrs
o	RUQ pain 
o	Vomiting 
•	72+ hrs
o	Increased confusion (encephalopathy)
o	Jaundice

Question 5

What are the signs?

Answer 5

• 0-24 hrs - no signs
• 24-72 hrs - liver enlargement and tenderness
• 72+ hrs - jaundice, coagulopathy, hypoglycaemia, renal angle tenderness

Question 6

What are the appropriate investigations?

Answer 6

• Measure paracetamol levels
o NOTE: peak paracetamol levels are 4 hrs after ingestion
• Others: FBC, U&Es, Glucose, LFTs, Clotting Screen, Lactate and ABG