Endotoxin Increases the Nephrotoxic Potential of Gentamicin and Vancomycin plus Gentamicin

Abstract
To assess the possible role of endotoxin as an amplification factor for experimental nephrotoxicity due to gentamicin plus vancomycin, rats were given continuous intravenous (iv) endotoxin or saline followed by twice-daily intraperitoneal (ip) saline, vancomycin (20 mg/kg ip), gentamicin (15 mg/kg subcutaneously), or both gentamicin and vancomycin. After 5 or 8 days of treatment, functional and histological parameters of renal function were evaluated: cortical drug levels, tritiated thymidine incorporation into cellular DNA, creatinine clearance, and appearance by light and electron microscropy. In animals not given endotoxin, only rats that received gentamicin plus vancomycin developed measurable abnormalities. Endotoxin did not cause nephrotoxicity in vancomycin-treated rats. However, in endotoxin-infused rats treated with gentamicin or gentamicin plus vancomycin for 8 days, the increase in blood urea nitrogen, decrease in creatinine clearance, and rise in renal cortical DNA synthesis were more severe than those in non-endotoxin-infused rats (P < .01). In these studies, endotoxin amplified the nephrotoxic potential of gentamicin alone and gentamicin plus vancomycin.