Enhancement of gentamicin nephrotoxicity by magnesium depletion in the rat.

This study examined the possible enhancement of gentamicin-induced nephrotoxicity by coexisting magnesium depletion. The effect of concurrent magnesium depletion on enhancing gentamicin-induced nephrotoxicity was measured by azotemia and mortality contrasted to magnesium repleted control rats also receiving gentamicin. After 28 days of dietary preparation, magnesium depleted rats and their magnesium repleted controls were each subdivided into 3 groups: (1) saline injection (NS); (2) gentamicin 80 mg/kg/day, and (3) gentamicin 120 mg/kg/day. Injections were continued for 14 days. All rats receiving gentamicin had proteinuria, increased mortality and significant renal morphological abnormalities. However, those rats which were concurrently magnesium depleted had statistically significant increments in BUN levels, more apparent renal tubular damage, and earlier mortality than the magnesium repleted controls. These observations support the view that concurrent magnesium deficiency in the rat enhanced gentamicin nephrotoxicity.