overdose - paracetamol Flashcards
1
Q
how does paracetamol cause toxic effect on the liver ?
A
small proportion of paracetamol is metabolised by CYP450 system enzymes to form a toxic metabolite (NAPQI)
usually conjugated by glutathione to a non-toxic compound and excreted in the urine. In overdose, the supply of glutathione is eventually depleted which allows NAPQI to exert hepatotoxic effects.
N-acetylcysteine (NAC) acts as a glutathione donor which can therefore conjugate with NAPQI and prevent hepatotoxicity. This needs to be administered within 8 hours of ingestion to ensure maximum efficacy
