Objective: To evaluate the need for prophylactic antibiotics in automated peritoneal dialysis (APD) patients undergoing flexible colonoscopy.

Patients and Methods: A total of 100 patients on automated peritoneal dialysis (APD) undergoing diagnostic colonoscopy were enrolled in a prospective randomized study. Patients were randomized into two age and sex matched groups; group A(50 patients) withintraperitoneal (IP)ceftazidimeprior to colonoscopy and group B(50 patients) without prophylactic antibiotics.Relation between peritonitis and different parameters were analyzed.

Results:Of all colonoscopies 61% showed normal findings, 15% with colonic polyps at different sites, 12% with angiodysplastic–like lesions, 6% with colonic ulcer (s), 4% with diverticulae without diverticulitis and 2% had transverse colon stricture. Post–colonoscopy peritonitis was documented in 4 (4%) and 5 (5%) patients in groups A and B respectively (p=0.4046); the causative organisms were mainly gram–negative bacteria. polypectomywas not associated with increased peritonitis episodes. By multiple logistic regression analysis, diabetes mellitus was the only independent variable that entered into the best predictive equation over the development of post–colonoscopy peritonitisbut not antibiotic use.

Conclusion:The relation between prophylactic antibiotic use prior to colonoscopy in APD patients and the risk of peritonitis was lacking.Only diabetes mellitus and age above 60 years appears to be of significance.Polypectomy did not increase peritonitis episodes.