Allopurinol influences aminophenazone elimination

Clin Pharmacokinet. 1990 Aug;19(2):167-9. doi: 10.2165/00003088-199019020-00006.


The authors observed an interaction between allopurinol and both theophylline and warfarin in 2 patients. To determine the possible effect of allopurinol on hepatic oxidative metabolism a [14C]-aminophenazone (aminopyrine) breath test was performed before and during treatment with allopurinol 100mg daily in 5 patients with hyperuricaemia. Allopurinol prolonged the [14CO2]-aminophenazone half-life from 72 +/- 13 to 104 +/- 16 minutes (mean +/- SEM, p less than 0.05). It is possible that allopurinol may produce clinically significant drug interactions through an inhibitory effect not only on xanthine oxidase metabolism but also on oxidative metabolism.

Publication types

  • Case Reports

MeSH terms

  • Allopurinol / pharmacology*
  • Aminopyrine / pharmacokinetics*
  • Breath Tests
  • Drug Interactions
  • Half-Life
  • Humans
  • Injections, Intravenous
  • Male
  • Middle Aged
  • Uric Acid / urine


  • Aminopyrine
  • Uric Acid
  • Allopurinol