[The Analgesic and Antipyretic Effects of a Non-steroidal Anti-inflammatory Drug, Oxaprozin, in Experimental Animals]

The analgesic and antipyretic effects of oxaprozin were investigated in comparison with those of indomethacin, ibuprofen, phenylbutazone and aspirin. On the various writhing tests in mice, the analgesic effect of oxaprozin was about 2 to 9 times more potent than those of ibuprofen, phenylbutazone and aspirin. On the other hand, the analgesic and antipyretic effects of oxaprozin in rats were roughly equivalent to those of aspirin, but less effective than those of the other drugs tested. On the urate synovitis test in dogs, only oxaprozin showed a prophylactic effect. Therefore, The effect of oxaprozin in mice and dogs was more potent than ibuprofen, phenylbutazone and aspirin. The metabolic rate of oxaprozin in rats is 3.5 and 7.2 times more rapid than in mice and dogs, respectively, and its blood level in rats is low. Moreover, the biological half-life of oxaprozin is 39 to 43 hr and 49 to 69 hr in dogs and humans, respectively. From these results, it is suggested that oxaprozin is more potent than ibuprofen, phenylbutazone and aspirin, and in clinical use, it is a long acting anti-inflammatory drug.