1Department of Medicine, Tri-Service General Hospital, National Defense Medical Center

Although excessive dose of piperacillin predominantly eliminated by the kidneys can cause encephalopathy in patients with impaired renal function, its standard dose causing acute neurotoxicity is rarely reported in advanced renal failure. We described a 63-year-old diabetes woman with advanced renal failure (estimated creatinine clearance of 8 mL/min) not yet dialysis received the standard dose of intravenous piperacillin/tazobactam (2 g/250 mg) every 6 hours for acute pyelonephritis with impending sepsis. Despite the controlled infection, she developed progressive mental confusion, bizarre behavior, and tremor 6 days later. A thorough survey including serum electrolyte, ammonia levels and computed tomography of brain was unremarkable except marked elevation of serum piperacillin concentration 86.9 µg/mL (therapeutic range 26 ± 15 µg/mL). Besides the withdrawal of piperacillin/tazobactam, the initiation of high-flux hemodialysis for 4 hours led to a dramatic decline in serum piperacillin concentration (22.2 µg/mL) and rapid reversal of neurological symptoms. Our case highlights the fact that the standard doses 8 g/day of piperacillin for advanced renal failure (CCr < 10 mL/min) may be excessive and a higher index of suspicion to piperacillin associated neurotoxicity is warranted in patients with advanced renal failure, even treated with the standard doses. High-flux hemodialysis can rapidly correct the life