paracetamol overdose

Question 1

paracetamol mechanism of action

Answer 1

blocks prostaglandins

Question 2

maximum dosage of paracetamol an adult can take in a day?

Answer 2

two 500mg tablets, 4 times in 24 hours

Question 3

how is paractamol metabolised and excreted?

Answer 3

• metabolised in liver
• excreted in urine as inactive glucuronide and sulfate conjugates

Question 4

when should blood tests be done for an overdose?

Answer 4

4 hours or more after suspected overdose as sampling before this time isn’t reliable as drug absorption and tissue distribution may still be active

Question 5

complications - paracetamol overdose

Answer 5

• liver failure
• kidney failure
• pancreatitis

Question 6

what drug needed for elevated paractamol levels?

Answer 6

• intravenous acetlycysteine
• prevents liver damage when given within 8 hours of overdose

Question 7

The picture on the left shows a piece of normal liver. The picture on the right shows a piece of liver from someone who took a paracetamol overdose. What
pathological process does this show?

Answer 7

• centrilobular necrosis
• due to the toxic effects of paracetamol metabolites on the liver cells, primarily in the centrilobular zone
• overdose overwhelms the liver’s detoxification pathways, leading to the formation of toxic metabolites that damage hepatocytes, resulting in necrosis or cell death in this central area of the liver lobule.