Serum antimicrobial concentrations for surgical antimicrobial prophylaxis in radical nephrectomy and radical prostatectomy

To evaluate the current methods of surgical antimicrobial prophylaxis from the viewpoint of pharmacokinetics for patients undergo urologic surgery, this study was designed to measure the serum concentrations of two different prophylactic antimicrobial agents in different types of urologic surgery. This prospective study included 39 patients with prostate cancer, renal pelvic cancer, ureteral cancer or renal cancer treated by radical surgery from August 2005 to March 2006. Blood samples were taken intraoperatively at 30 min and 180 min after the beginning of the first administration. The half-life of the beta phase of cefazolin is 2.46 h and that of piperacillin is 0.7 h according to their manufacturers. The average serum concentration of cefazolin at 30 min was 144 μg/mL in the prostatectomy group and 175 μg/mL in the nephrectomy group. At 180 min, the average concentration of cefazolin was 37 μg/mL in prostatectomy group and 59 μg/mL in the nephrectomy group. The average concentration of piperacillin at 30 min was 134 μg/mL in the prostatectomy group and 137 μg/mL in the nephrectomy group. At 180 min, the average concentration of piperacillin was 10 μg/mL in the prostatectomy group and 22 μg/mL in the nephrectomy group. Thus, the concentration at 180 min after the beginning of infusion was different according to the half-life of each antimicrobial agent. Therefore, up-to-date guidelines for surgical antimicrobial prophylaxis that deal with additional types of intraoperative prophylaxis should be consulted if the operation exceeds two half-lives of the prophylactic antimicrobial agents used in real-life clinical practice.