Paracetamol Overdose

Question 1

What is classed as an acute paracetamol overdose?

Answer 1

Injection within 1 hour or less
Severe if >75mg/kg

Question 2

What is classed as staggered ingestion in paracetamol overdose?

Answer 2

Ingestion over an hour or longer
Severe >150mg/kg in 24hours

Question 3

Where is paracetamol metabolised?

Answer 3

Liver

Question 4

How long does it take to reach peak paracetamol conc?

Answer 4

4hours

Question 5

What is the half life of paracetamol?

Answer 5

2 houes

Question 6

What are some common symptoms of paracetamol overdose? (3)

Answer 6

Nausea
Vomiting
Abdo pain

Question 7

What could be seen on an ABG in a paracetamol overdose? (2)

Answer 7

Metabolic acidosis
Raised lactate

Question 8

What are the main symptoms of a paracetamol overdose? (7)

Answer 8

• Nausea & vomiting
• Anorexia
• Malaise
• Abdominal pain
• Altered mental status
• Confusion
• Scars: evidence of previous self-harm

Question 9

What signs can be seen in a paracetamol overdose? (7)

Answer 9

○ Asterixis
○ Bruising
○ Jaundice
○ Right upper quadrant pain
○ Oliguria/anuria
○ Tachycardia/hypotension
○ Coma

Question 10

When are people hospitalised in paracetamol overdoses? (5)

Answer 10

• Symptomatic patients
• Ingestion of ≥75 mg/kg of paracetamol over an hour or less
• Ingestion of ≥75 mg/kg but the time of ingestion is uncertain
• Any patient who has taken a staggered overdose
• Ingestion of more than the licensed dose (4g/24 hours for adults) and the total dose is ≥75 mg/kg within 24 hours, OR, <75 mg/kg within 24 hours for each of the preceding 2+ days.

Question 11

What is the main drug treatment in a paracetamol overdose?

Answer 11

N-acetylcysteine

Question 12

When should paracetamol levels be taken?

Answer 12

No earlier than 4 hours since last ingestion

Question 13

When is the paracetamol ingestion graph mainly used?

Answer 13

For patients who have ingested paracetamol over one hour or less and presented within 8 hours

Question 14

When would detectable paracetamol levels be concerning?

Answer 14

If it’s over 16hours after ingestion

Question 15

How is N-acetylcysteine given in a paracetamol overdose?

Answer 15

IV

Question 16

How many infusions of n-acetylcysteine are given in a paracetamol overdose?

Answer 16

3

Question 17

What test is done after 21 hour regimen of n-acetylcysteine in a paracetamol overdose?

Answer 17

Blood tests to look for hepatic impairment

Question 18

What is seen in an anaphylactoid reaction to n-acetylchsteine? (6)

Answer 18

Nausea
Vomiting
Urticarial rash
Angioedema
Tachycardia
Bronchospasm

Question 19

What should be done if someone develops an anaphylactoid reaction to n-acetylcysteine treatment?

Answer 19

Temporarily stop infusion
Consider chlorohenamine and nebulised salbutamol
Once reaction has settled restart infusion at a slower rate

Question 20

When can activated charcoal be given in a paracetamol overdose?

Answer 20

Presentation within 1 hour

Question 21

Person presents with acute paracetamol overdose what should you do?

Answer 21

Give activated charcoal if <1 hour
Wait 4 hours since ingestion and then take paracetamol levels
Take bloods for hepatic injury
If hepatic injury/above treatment line/has been over 8hours then start NAC treatment

Question 22

Person has presented with an acute paracetamol overdose and last ingestion was over 8 hours ago. What do you do?

Answer 22

Take urgent paracetamol levels
Take bloods for hepatic injury
Start nac immediately if taken over 150mg/kg
If above therapeutic line/have hepatic injury then continue NAC

Question 23

Patient has a staggered paracetamol overdose. What should you do?

Answer 23

Immediately start NAC
Take paracetamol levels 4 hours after last ingestion
Take bloods for hepatic injury