Comparative nephrotoxicity of gentamicin and netilmicin: functional and morphological correlations with urinary enzyme activities.

An increase in urinary enzyme activities reflected biopsy confirmed aminoglycoside nephrotoxicity (proximal tubular injury) before changes in blood urea nitrogen, serum creatinine, urinary osmolality and urinary protein excretion. Netilmicin, a semisynthetic derivative of gentamicin, was less nephrotoxic than gentamicin.