An LLC-PK1 cell culture model was used to evaluate for a direct protective effect of the pentoxifylline analogue HWA-448 in gentamicin nephrotoxicity at the cellular level. Cells exposed to 2 mM gentamicin for 6 days displayed a significant decrease in specific activities of leucine aminopeptidase, NaK ATPase, and N-acetyl glucosaminidase, and an increase in total cellular phospholipids (P < .05). Concomitant exposure to 0.125 mM HWA-448, a dose that did not alter cellular enzymes or total phospholipids under physiologic conditions, prevented the alterations in marker enzymes and total phospholipids induced by gentamicin (P < .05). Gentamicin binding and uptake studies revealed 0.125 mM HWA-448 had no effect on LLC-PK1 cell plasma membrane binding or cellular gentamicin uptake. We conclude that HWA-448 ameliorates gentamicin-induced alterations in LLC-PK1 cell enzymes and phospholipids by a mechanism independent of plasma membrane binding or cellular uptake.