Relationship between vancomycin-associated nephrotoxicity and the number of combined nephrotoxic agents

Vancomycin is associated with nephrotoxicity; however, the influence of the number of combined nephrotoxic agents on the incidence of vancomycin nephrotoxicity has not been clarified. We investigated patient backgrounds in 148 inpatients who received vancomycin treatment. The patients were divided into nephrotoxicity (n=35) and non-nephrotoxicity (n=113) groups. A comparison of the patient backgrounds in the two groups revealed significant differences in weight, changes in serum creatinine before vancomycin administration, blood urea nitrogen to serum creatinine ratio, length of vancomycin therapy, vancomycin trough concentration, and number of combined nephrotoxic agents. Multiple logistic regression analysis using these six factors as autonomous variables showed that the highest vancomycin trough concentration (odds ratio, 1.080; 95% confidence interval, 1.030-1.140; p = 0.003) and the number of combined nephrotoxic agents (odds ratio, 1.590; 95% confidence interval, 1.120-2.260; p = 0.010) were significantly related to nephrotoxicity.