Chemistry Reference
In-Depth Information
O
OH
CYP450
N
CH
3
N
CH
3
H
O
O
H
2
N-Protein
Glutathione
OH
OH
H
N
S
glutathione
Protein
N
N
CH
3
CH
3
H
H
O
O
Figure 5.7
Role of glutathione in toxicity of paracetamol.
However, if paracetamol is taken in overdose, the levels of quinoneimine
exceed the ability of glutathione to convert it back to paracetamol and toxi-
city to the liver results. In some cases, if treatment is not initiated in time,
severe toxicity results, leading to death by acute liver failure. Treatment of
paracetamol overdose is by administration of
N-
acetylcysteine (Figure 5.8).
This compound (the acetyl derivative of the essential amino acid cysteine)
functions as an alternative source of thiol (
SH) groups, which act in a
similar manner to glutathione to detoxify the quinoneimine.
a
O
H
H
N
CH
3
HS
COOH
Figure 5.8
The structure of N-acetylcysteine.
