This study is aimed to demonstrate that renal impairment caused by administration of amikacin (AMK) alone can be lessened by co-administration of piperacillin (PIPC). The patients in the present study were divided into three groups. In "group P" and "group A", PIPC alone and AMK alone were administered, respectively. In "group P+A", PIPC and AMK were co-administered. Dosage of AMK was individualized based upon the therapeutic drug monitoring method, and that of PIPC was adjusted depending upon the creatinine clearance of a patient. In group A, urinary concentrations of β2-microglobulin and lysozyme, and urinary excretion of j32-microglobulin, lysozyme and r-GTP per day were significantly higher (p<0.05) than those in group P. These differences were not observed, however, between group P and group P+A. The trough value of AMK, 11 days after AMK administration, was significantly higher in group A (p<0.05) than that in group P+A. Incidence of renal impairment, as judged from urinary excretion of j92-microglobulin per day and urinary lysozyme concentration, was significantly higher in group A (p<0.05) than that in group P+A. These findings indicate that co-administration of PIPC with AMK can lessen the renal impairment caused by administration of AMK alone.
