Nephrotoxicity studies on aspirin and diflunisal.

Some of the difficulties encountered in investigations of long-term drug nephrotoxicity are reviewed, and the evidence for acute and chronic renal damage induced by aspirin is discussed. Two studies were carried out to investigate the acute effects of diflunisal on the kidney, and to compare its effects with those of aspirin. Measurements were made before, during and after drug intake, of epithelial cells and lysosomal enzyme (beta-d-n-acetyl glucosaminidase) excretion in urine. Diflunisal caused no change in cell excretion and no increase in enzyme secretion in 6 normal volunteers. In a comparative study against aspirin, two groups of 12 patients being treated for osteoarthrosis were observed over an 8-week period. Enzyme excretion increased in both groups and appeared to be dose related. The increase, however, was relatively greater in the aspirin group. The possible significance of these findings is discussed.