Paracetamol Overdose Flashcards
Definition
Excessive ingestion of paracetamol causing toxicity
Aetiology
· MAX recommended dose: 2 x 500 mg tablets, 4 x in 24 hrs
· Intake > 12 g can cause hepatic necrosis
Risk factors
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
Epidemiology
· Most COMMON intentional drug overdose in the UK
· Causes 100 deaths/yr in the UK
Presenting symptoms
· IMPORTANT: 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
Signs on physical examination
· 0-24 hrs - no signs
· 24-72 hrs - liver enlargement and tenderness
· 72+ hrs - jaundice, coagulopathy, hypoglycaemia, renal angle tenderness
Investigations
· Measure paracetamol levels
o NOTE: peak paracetamol levels are 4 hrs after ingestion
· Others: FBC, U&Es, Glucose, LFTs, Clotting Screen, Lactate and ABG