Paracetamol Overdose

Question 1

what is the medical name for paracetamol?

Answer 1

acetaminophen

Question 2

what are the features of paracetamol overdose?

Answer 2

• no symptoms
• nausea and vomiting
• loin pain
• haematuria and proteinuria
• jaundice
• abdominal pain
• coma
• severe metabolic acidosis

Question 3

what is the pathophysiology of paracetamol overdose?

Answer 3

1. build-up of toxic NAPQI
2. NAPQI inactivated by glutathione
3. glutathione stores are rapidly depleted –> NAPQI un-metabolised
4. liver and kidney damage

Question 4

what is the management of a paracetamol overdose if dose was >150mg/kg and ingested <1 hour ago?

Answer 4

activated charcoal

Question 5

what is the management of a paracetamol overdose if staggered overdose or ingested >15 hours ago?

Answer 5

start n-acetylcysteine immediately

Question 6

what is the management of a paracetamol overdose if ingested <4 hours ago?

Answer 6

• wait until 4 hours to take a level
• treat with n-acetylcysteine

Question 7

what is the management of a paracetamol overdose if ingested 4-15 hours ago?

Answer 7

• take immediate level
• treat with n-acetylcysteine

Question 8

what bloods should be checked in paracetamol overdose?

Answer 8

• FBC
• urea and electrolytes
• INR
• venous gas

Question 9

what is a know side-effect of n-acetylcysteine?

Answer 9

anaphylactoid reaction
temporarily stop the transfusion and restart at a lower rate

Question 10

what leaves patients at increased risk of toxicity in paracetamol overdose?

Answer 10

• patient on long-term enzyme inducers
• regular alcohol excess
• pre-existing liver disease
• glutathione-deplete states - eating disorders, malnutrition, HIV