Interaction between levofloxacin and vancomycin in rats--study of serum and organ levels

The changes of pharmacokinetic parameters when levofloxacin (LVFX) and vancomycin (VCM) were administered concomitantly were studied in rats. There was an increase in the AUC and Tmax of LVFX with concomitant administration, but no effect on Cmax. There was also an increase in the AUC and T1/2 of VCM with concomitant administration, while Vd was reduced. Concomitant administration had no effect on the correlation between the serum and hepatic tissue concentrations of LVFX, but it markedly decreased the correlation between the serum and renal tissue concentrations of VCM. BUN was increased at 8 h after the administration of VCM. There have been reports that renal dysfunction can be caused by VCM, and our findings suggested that concomitant administration of LVFX and VCM must be performed with caution.