Alterations in Cisplatin Pharmacokinetics and Its Acute/Sub-chronic Kidney Injury over Multiple Cycles of Cisplatin Treatment in Rats.

Cisplatin (CDDP)-induced acute kidney injury (AKI) is a major clinical concern. CDDP treatment is generally conducted with multiple cycles; the magnitude of the CDDP-induced AKI may be altered by these cycles. Moreover, sub-chronic kidney injury (sCKI) induced by repeated CDDP treatment is often associated with renal interstitial fibrosis, potentially leading to chronic kidney disease. Therefore, it is suggested that the management of not only AKI but also sCKI induced by CDDP in multiple cycles plays an important role in the outcome of CDDP-based chemotherapy. This study investigated the alteration in pharmacokinetics and toxicodynamics of CDDP that was repeatedly administered for three cycles in rats; a cycle consisted of CDDP (5.0 mg/kg, bolus injection) followed by a 21-d washout period. AKI and sCKI were evaluated by plasma creatinine concentration. In repeated multiple administration of CDDP, renal clearance was decreased and the amounts of accumulated Pt in kidneys increased by the cycle. AKI and sCKI were similarly exacerbated by the cycle, whereas the degree of AKI showed a large inter- and intra-individual variation in each cycle. However, the degree of sCKI constantly increased (creatinine increasing ratio in any cycle is about 150%), suggesting that the degree of sCKI in any given cycle was predictable by monitoring the initial creatinine baseline. In this study, therefore, it is suggested that the evaluation of sCKI by monitoring creatinine concentration at base is important for the estimation of CDDP-induced nephrotoxicity. These results may provide useful information for more effective and safe CDDP-based chemotherapy with evidence-based dose adjustment.