The usefulness of icodextrin-containing peritoneal dialysis (PD) solution for the management of body fluid and blood pressure has been reported. However, icodextrin PD solution is a foreign solution in the body, and the possible induction of intraperitoneal inflammation has been reported. In this study, we investigated at 6-month intervals the influence of icodextrin solution on peritoneal permeability and inflammatory reactions in patients in whom glucose solution had been changed to icodextrin solution for the overnight dwell. We enrolled 9 anuric PD patients (5 men, 4 women) of mean age 58 +/- 5.9 years (range: 45.6-64.8 years) into the study. The patients' mean duration of PD was 61.9 +/- 42 months (range: 6.7-142.5 months). The cause of end-stage renal disease was chronic glomerulonephritis in all patients. For evaluation ofperitoneal permeability, we performed peritoneal equilibration tests (PETs) immediately after an overnight dwell and determined the dialysate-to-plasma ratios of creatinine (D/P Cr), beta2-microglobulin (D/P beta2m), albumin (D/P Alb), immunoglobulin G (D/P IgG), and alpha2-macroglobulin (D/P alpha2m). We also measured interleukin-6 (IL-6) and fibrinogen degradation products (FDPs) in overnight effluent as indices of inflammation and of the fibrinolysis-coagulation system. The evaluation was performed every 6 months for 24 months. The FDPs in effluent increased significantly at 6 months after the change to icodextrin solution, and IL-6 tended to increase. The D/P beta2m, D/P Alb, D/P IgG, and D/P alpha2m all significantly increased in the course of follow-up. In the PETs, the D/P Cr increased slightly, but the change was nonsignificant. At 30 months after the change to icodextrin solution, 1 patient was diagnosed as having a risk of encapsulating peritoneal sclerosis (pre-EPS). In this patient, rapid increases in IL-6, D/P Cr and macromolecular and small molecular D/P by PET were noted after the change to icodextrin solution. Steroids were administered after the diagnosis of pre-EPS, with the result that the IL-6 level rapidly decreased and the D/P Cr and D/P of small molecules and macromolecules slightly decreased. Icodextrin dialysis solution increased peritoneal permeability. Although the cause was unclear, icodextrin may have changed peritoneal reactivity. Long-term use of icodextrin PD solution requires further investigation.