[The differentiation of potential nephrotoxicity of various aminoglycosides in animal experiments]

Experimental differentiation in the animal of nephrotoxicity of various aminoglycosides. Animal experiments showed that all aminoglycosides cause similar toxic tubular and glomerular damage when investigated by qualitative morphology. Quantitative differences in tubular nephrotoxicity of gentamicin, tobramycin, sisomicin, kanamycin, kanendomycin, amikacin, and butirosin were demonstrable by evaluation of the excretion rates of tubular cells and urinary enzymes in rats. By this means dose-effect-relationships were found resulting in reproducible different toxic threshold doses for each antibiotic, and thus in a scale of increasing nephrotoxicity. The aminoglycosides differed by their affinity to kidney tissue as measured by determination of the accumulating renal concentrations of the drugs at different times during multiple-dose administration. This had a modifying influence on excretion rates of cells and enzymes affecting the scale of toxicity in long-term studies. Comparative investigations on nephrotoxicity in rats and guinea pigs gave similar results. In addition, a study in man suggested that the test results of nephrotoxicity are not species-specific. For human therapy it is concluded that even more caution should be practised with the new aminoglycosides than with gentamicin in order to avoid renal damage.