Tubular-toxic effects of aminoglycosides and their combinations with cephalosporins.

Cephalosporins have a distinctly different effect from that of aminoglycosides on membranes of the proximal tubule of the human kidney as measured by urinary AAP concentrations. Except for a slight influence by cephacetrile, cephalosporins showed no effect on the proximal tubule. In contrast, after three days of administration, the aminoglycosides caused a cumulative increase in membrane proteins of the proximal tubule to be excreted in the urine. Tobramycin appears to have the least and amikacin the greatest effect on the brush border membranes of the proximal tubule of the normal human kidney. The combination of cephalosporins with aminoglycosides increases the potential toxic effect on the proximal tubule.