NAPQI

NAPQI

Clinical data
Other names	N-Acetyl-p-benzoquinone imine; N-Acetylimidoquinone
Identifiers
IUPAC name N-(4-Oxo-1-cyclohexa-2,5-dienylidene)acetamide
CAS Number	50700-49-7 N
PubChem CID	39763
IUPHAR/BPS	6299
ChemSpider	36356 Y
UNII	G6S9BN13TI
ChEBI	CHEBI:29132 Y
ChEMBL	ChEMBL33232 Y
CompTox Dashboard (EPA)	DTXSID20198756
ECHA InfoCard	100.168.312
Chemical and physical data
Formula	C8H7NO2
Molar mass	149.149 g·mol−1
3D model (JSmol)	Interactive image
SMILES CC(=O)N=c1ccc(=O)cc1
InChI InChI=1S/C8H7NO2/c1-6(10)9-7-2-4-8(11)5-3-7/h2-5H,1H3 Y Key:URNSECGXFRDEDC-UHFFFAOYSA-N Y
NY (what is this?)  (verify)

NAPQI, also known as NAPBQI or N-acetyl-p-benzoquinone imine, is a toxic byproduct produced during the xenobiotic metabolism of the analgesic paracetamol (acetaminophen).^[1] It is normally produced only in small amounts, and then almost immediately detoxified in the liver.

However, under some conditions in which NAPQI is not effectively detoxified (usually in the case of paracetamol overdose), it causes severe damage to the liver. This becomes apparent 3–4 days after ingestion and may result in death from fulminant liver failure several days after the overdose.