Gentamicin and sisomicin - induced renal tubular damage.

Early signs of aminoglycoside - induced renal tubular damage were detected in 26 patients given gentamicin and 23 given sisomicin. The urinary elimination of 3 low molecular weight proteins (LMWP) - beta 2 microglobulin, retinol binding protein and lysozyme (LZM), and the urinary activity of 2 enzymes - alanine aminopeptidase and N-acetyl-beta-glucosaminidase - was measured before, during and after treatment. In gentamicin - treated patients LMWP elimination increased, especially LZM which rose markedly during treatment and returned to normal values after its end. Enzyme activities also rose while gentamicin was being given. Sisomicin produced smaller changes. As neither the mean serum creatinine nor the mean urinary elimination of transferrin were increased, glomerular function was probably not affected. However, tubular damage was detected, as shown by the LMWP output (especially LZM) and increased enzyme activity. Urinary LMWP and enzyme measurements are presented as sensitive and reliable methods to monitor early aminoglycoside - induced tubular impairment. It is suggested that the different renal toxicities of gentamicin and sisomicin are related to differences in their accumulation in the renal cortex.