[Combinatorial Vancomycin and Piperacillin/Tazobactam Results in Elevated Vancomycin Trough Concentration and Acute Kidney Injury: A Case Report].

In the hospital, antibiotics are widely used to treat infections. We report a case of acute kidney injury (AKI) caused by an antibiotic drug combination. A 30-year-old Japanese male presented with lung metastases, pneumothorax, empyema, and methicillin-resistant Staphylococcus aureus (MRSA) infection. The patient received a combination of vancomycin and piperacillin/tazobactam, which resulted in elevated vancomycin trough concentration and subsequently in AKI. Renal function was restored upon vancomycin and piperacillin/tazobactam cessation. Though this patient had AKI most likely due to the combined use of two agents as has been reported in many cases, vancomycin trough concentration showed an unexpected abnormal increase when halting vancomycin treatment. This is the first report indicating a drug-drug interaction between vancomycin and piperacillin/tazobactam with unexpected abnormal vancomycin trough concentration, leading to AKI, additionally we think that there was a situation that he stressed against the kidney by a history of medications caused renal dysfunction and co-administration. We suggest that when using vancomycin in combination with piperacillin/tazobactam, the trough concentration of vancomycin must be confirmed simultaneously with renal function and evaluation, and that the combination of these two drugs should be minimized.