Comparative metabolic studies of phenacetin and structurally-related compounds in the rat

Xenobiotica. 1976 Apr;6(4):217-36. doi: 10.3109/00498257609151632.


1. A comparative study of the metabolism of [acetyl-14C]phenacetin, [acetyl-14C]methacetin, [acetyl-14C]paracetamol and [acetyl=14C]acetanilide in the rat is reported. 2. The extent of N-deacetylation, evidenced by the measurement of respired 14CO2, varied, being greatest with acetanilide (25-31%) and least with paracetamol (6%). 3. The major urinary metabolites in each case were N-acetyl-p-aminophenyl sulphate and N-acetyl-p-aminophenyl glucuronide; the relative proportions varied with the sex of the animals and as a result of extended dosage. 4. The metabolism of [ethyl-14C]phenacetin and [ethyl-14C]phenetidine was investigated and the extent of O-dealkylation determined by measurement of respired 14CO2. 5. The metabolic pathways of some related glycolanilides and oxanilic acids included N-deacylation, and in the glycolanilides, oxidation of the glycollic group.

Publication types

  • Comparative Study

MeSH terms

  • Acetaminophen / pharmacology
  • Acetanilides / metabolism
  • Animals
  • Chromatography, Thin Layer
  • Female
  • Glucuronates / metabolism
  • Male
  • Phenacetin / analogs & derivatives*
  • Phenacetin / metabolism*
  • Phenacetin / pharmacology
  • Rats
  • Sex Factors
  • Structure-Activity Relationship
  • Sulfuric Acids / metabolism


  • Acetanilides
  • Glucuronates
  • Sulfuric Acids
  • Acetaminophen
  • Phenacetin