Antipyrine

Phenazone

Clinical data
ATC code	N02BB01 (WHO) S02DA03 (WHO)
Pharmacokinetic data
Biological half-life	12 hours
Identifiers
IUPAC name 1,2-Dihydro-1,5-dimethyl-2-phenyl-3H-pyrazol-3-one
Synonyms	analgesine, antipyrine
CAS Number	60-80-0 Y
PubChem CID	2206
DrugBank	DB01435 Y
ChemSpider	2121 Y
UNII	T3CHA1B51H
KEGG	D01776 Y
ChEBI	CHEBI:31225 Y
ChEMBL	CHEMBL277474 Y
ECHA InfoCard	100.000.442
Chemical and physical data
Formula	C11H12N2O
Molar mass	188.2258g/mol
3D model (Jmol)	Interactive image
SMILES O=C2\C=C(/N(N2c1ccccc1)C)C
InChI InChI=1S/C11H12N2O/c1-9-8-11(14)13(12(9)2)10-6-4-3-5-7-10/h3-8H,1-2H3 Y Key:VEQOALNAAJBPNY-UHFFFAOYSA-N Y

Phenazone (INN and BAN; also known as phenazon, antipyrine (USAN), or analgesine) is an analgesic, a non-steroidal anti-inflammatory drug and an antipyretic. It was first synthesized by Ludwig Knorr in 1887. Phenazone is synthesized by condensation of phenylhydrazine and ethyl acetoacetate under basic conditions and methylation of the resulting intermediate compound 1-phenyl-3-methylpyrazolone with dimethyl sulfate or methyl iodide. It crystallizes in needles which melt at 156 °C. Potassium permanganate oxidizes it to pyridazine tetracarboxylic acid. Phenazone has an elimination half life of about 12 hours. Indication: Used to relieve pain and fever. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver.

Possible adverse effects include: