Comparison of the urate lowering effects of allopurinol and diflunisal.

The urate lowering effect of diflunisal, a fluorinated salicylate with an antiinflammatory action, was compared with that of allopurinol in a crossover study. When patients took diflunisal the mean serum urate was significantly greater than on allopurinol but still was within the optimal range in 6 of 8 patients studied. This effect was consistent with its uricosuric action. No inhibition of xanthine oxidase activity by diflunisal was found. Diflunisal could be particularly useful in patients who require a drug with both a uricosuric and an antiinflammatory effect.