Renal toxicity. Tobramycin and gentamicin.

The new aminoglycoside, tobramycin sulfate, has been shown to be effective against the same microorganisms for which gentamicin is currently employed. This study compares the effects of these two antibiotics on renal function and ultrastructure in guinea pigs. Significant differences in the blood urea nitrogen of treated and nontreated groups, as well as between the gentamicin- and tobramycin-treated groups were observed. Gentamicin produced greater, more rapid elevations of the blood urea nitrogen, although all elevations were reversible. The ultrastructural pathology produced by tobramycin was similar to that previously described for gentamicin.