What is paracetamol’s mechanism of action?How does it differ from Aspirin?

Peripherally: Weak COX-1 and COX-2 inhibitor. It is analgesic and antipyretic and it has no anti-inflammatory action. It does not any effect on platelet aggregation, unlike Aspirin. Aspirin also inhibits COX-1 and COX-2 irreversibly.

CNS: Blocks COX-3 and the %-HT descending pain pathways and it inhibits NMDA receptors, reducing nociception. This means neurotransmitters can't bind to receptors and the pain perception is blocked.

 

Name the indications for paracetamol.  Under which circumstances is it a drug of choice for the treatment of mild pain and fever? 

• It is used for the relief of mild to moderate pain of somatic origin
• Suitable for patients in which NSAID's are contraindicated
• It is the drug of choice for children
• Used when anti-inflammatory effect is not needed

 

Name side-effects that can occur with paracetamol use.  Concentrate only on general side effects and not on acute paracetamol overdose.

• skin rash
• urticuria

 

Compile a report in which you discuss acute paracetamol toxicity, stressing the dose, signs and symptoms and treatment.

Signs and symptoms: within 1-2 days:

• nausea and vomiting
• abdominal pain
• fatigue and weakness

Signs and symptoms: after 1-2 days:

• light subcostal pain
• tar liver
• jaundice
• liver necrosis
• death

 

Dose:

• 10-15g is a fatal dose
• Paracetamol poisoning can develop due to the chronic use of 2g a day

 

Treatment:

• Within one hour of overdose, induce vomiting or administer activated charcoal
• Liver damage can be prevented by administering NAC within 12 hours after overdose. 
• N-acetycystein administered IV within 8-12 hours
• Oral treatment: acetylcysteine or carbocistein
• Treatment is only effective within 10 hours of poisoning