Abstract:
Background: Current guideline suggested that intraperitoneal (IP) antibiotics should be administered only in a long peritoneal dialysis (PD) dwell (≥6 hours) which is not always practical because the long dwell might result in low ultrafiltration and volume overload. The objectives of this study were to develop a novel regimen for IP antibiotics in short dwell (≤2 hours) and examine the dialysate and plasma level of the most used empirical antibiotics for PD-related peritonitis, cefazolin and ceftazidime. Methods: In the novel regimen, cefazolin and ceftazidime (20 mg/kg each) were added in a 5-liter bag of 2.5% dextrose PD fluid which was placed on the warmer of the PD cycling machine. Another 5-liter bag of PD fluid was connected to the machine, off the warmer. Patients underwent 5 exchanges of 2-liter PD fluid over 10 hours by the PD cycling machine without last fill or additional dwell. The machine took PD fluid from the on-warmer bag and infused to the patient. The on-warmer bag was then replete by PD fluid from the off-warmer bag before the next exchange. Plasma samples were collected at time 0, 0.5, 1, 1.5, 2, 4, 6, 8, 10, 14, 18, and 24 hours. Dialysate samples from each exchange were collected at time 0, 2, 4, 6, 8, and 10 hours. Cefazolin and ceftazidime concentrations in plasma and dialysate were determined by high performance liquid chromatography. Results: Six PD patients without peritonitis were participated in the study. Dialysate cefazolin and ceftazidime were consistently high throughout the PD session in all patients (26-360 mg/L). Plasma cefazolin and ceftazidime exceeded the minimal inhibitory concentration (MIC) for susceptible organisms (≤8 mg/L) within 2 hours (cefazolin 28.5±8.0 and ceftazidime 12.5±3.4 mg/L at 2 hours), peak at 10 hours (51.1±14.1 and 23.0±5.2 mg/L) and then sustained well above the MIC at 24 hours (42.0±9.6 and 17.1±3.1 mg/L). Conclusion: The novel regimen for IP cefazolin and ceftazidime in short dwell (≤2 hours) could provide adequate dialysate and plasma concentration. This daily IP cefazolin and ceftazidime regimen would become a standard regimen for peritonitis in PD patients already using PD cycling machine as well as some continuous ambulatory PD (CAPD) patients who need shorter dwells during peritonitis due to increasing peritoneal solute transport.