Vancomycin does not enhance amikacin-induced tubular nephrotoxicity in children

A three-drug antibiotic regimen including vancomycin and amikacin has been recommended as effective treatment in clinical settings in which Gram-positive bacteremias are a serious problem. To determine if vancomycin potentiates the tubular proteinuria associated with amikacin therapy, we studied febrile, neutropenic children with leukemia who were treated with either amikacin (800 mg/m2/day) and ticarcillin-clavulanate or with vancomycin (1.2 g/m2/day), amikacin and ticarcillin. Tubular proteinuria was assessed in 14 children by monitoring the excretion of total urinary protein and two other sensitive indicators of nephrotoxicity, the renal tubular enzymes N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase, in sequential 8-hour urine collections during 7 days of antimicrobial therapy. There were no significant differences between the two treatment groups in excretion of the three marker proteins when values were compared on any day of therapy or for the entire 7-day course. Nor did we observe any significant changes in either serum creatinine concentrations or amikacin clearance rates in the larger study group of 101 children from which these patients were drawn. Although amikacin was subclinically nephrotoxic, the addition of vancomycin to amikacin therapy did not enhance clinical or tubular nephrotoxicity in these children.