Nephrotoxicity and drug interaction of vancomycin(2)

Vancomycin hydrochloride (VCM) has an antibacterial action against Gram positive bacteria, e.g., Methicillin-resistant Staphylococcus aureus (MRSA). In the clinical situation, there are patients with serious infections, being infected with not only MRSA, but also with Gram negative bacteria like Pseudomonas aeruginosa. Because VCM has the adverse reaction of nephrotoxicity, we are apprehensive about using VCM with other antibiotics, which might increase this problem. Therefore, the nephrotoxic effects and pharmacokinetics of VCM were examined in rabbits and compared with those in rabbits administered with VCM and other antibiotics. Responses indicating nephrotoxicity such as increases of serum creatinine concentration and BUN and morphological changes of the kidney were induced by the single injection of VCM at 300 mg/kg, i.v. In contrast, no abnormality of clinical data and morphological alteration were observed in the groups injected with VCM and imipenem (IPM)-cilastatin sodium (CS), flomoxef sodium (FMOX) or fosfomycin sodium (FOM). This was not true for groups injected with VCM and ceftazidime, cefpimizole sodium (CPIZ) or cefoperazone sodium. Clearance of VCM increased obviously in the groups injected with VCM and IPM-CS, FMOX or FOM, but decreased in those given VCM and CPIZ. Since the renal concentrations of VCM in the groups that were administered VCM with IPM-CS, FMOX or FOM were lower than that in the control group, IPM-CS, FMOX and FOM may decrease the nephrotoxicity of VCM by inhibiting its uptake into the kidney.