evaluation of analgesic activity of allopurinol and febuxostat in experimental analgesic models in mice

Background: Allopurinol and febuxostat are xanthine oxidase inhibitors which are used in the treatment of hyperuricemia and gout. Pain is one of the important symptoms in gout patients. The present study was to evaluate the analgesic activity of allopurinol and febuxostat in two analgesic models in mice. Materials and Methods: The analgesic activity of allopurinol (39 mg/kg) and febuxostat (15.6 mg/kg) was evaluated using central analgesic model of Eddy′s hot plate and peripheral analgesic model of acetic acid induced writhing. Both drugs were compared with the positive control, pentazocine for a hot plate method and aspirin for the writhing method. Furthermore, both allopurinol and febuxostat were compared with each other. Results: Both allopurinol and febuxostat showed significant increase in reaction time at various time periods in hot plate method and also showed significant delay in onset of writhing as well as decrease in number of writhes in writhing method. As compared to positive control result, allopurinol and febuxostat result were lower. Febuxostat shows better analgesic activity as compared to that of allopurinol. Conclusion: Allopurinol and febuxostat exhibited analgesic activity in both central and peripheral models of pain.