Effective peritoneal capillary blood flow (EPBF) was evaluated by calculating the diffusive mass transport coefficient of carbon dioxide during intermittent peritoneal dialysis (IPD) performed with the intraperitoneal administration of sodium nitroprusside (NP), chlorpromazine (CP), or isoproterenol (IP) in the doses 5, 2.5, and 0.5 mg/L, respectively. Peritoneal transfer rates of substances of different molecular size and charge were simultaneously examined and compared with EPBF. EPBF (mL/min) was 220 +/- 40 (+/- SEM) for NP (n = 11), 224 +/- 29 for CP (n = 10), and 243 +/- 35 for IP (n = 10). These values did not differ significantly from those obtained during dialysis without drugs (223 +/- 22 mL/min, n = 20). NP, CP, and IP did not cause any significant changes in peritoneal transfer of carbon dioxide. Transfer rates of bicarbonate and total carbon dioxide were increased only with NP. All drugs enhanced the peritoneal removal of sodium, potassium, urea, and uric acid. Total protein loss was enhanced by all drugs except IP. With statistically similar EPBF during dialysis, the augmenting effect of NP and IP on small solute removal was the most pronounced. These results indicate that EPBF is not a major factor in the changes in peritoneal transfer rates during dialysis performed with NP, CP, or IP.