Tolvaptan increases urine and ultrafiltration volume for patients with oliguria undergoing peritoneal dialysis

Hypoalbuminemia caused by peritoneal dialysate protein loss, frequently occurs in patients on peritoneal dialysis (PD) and is associated with an increased risk of death. We investigate whether PD dialysis exchange volume (PD volume) could be reduced with tolvaptan (TVP) through increased urine volume (UV).

The study included 11 stable patients with oliguria undergoing PD. The following parameters were examined-diuretic response and the effect of TVP on peritoneal ultrafiltration (UF), body weight, serum albumin, sodium, arm muscle area (AMA), PD volume, dialysis efficiency calculator (K t/V), and urine and serum osmolarity (OSM).

The average UV increased from 428 ± 178 to 906 ± 285 mL (p = 0.018 by paired t test). Average weekly PD volume decreased from 28,836 ± 5,699 to 23,872 ± 3,569 mL (p = 0.04 by paired t test). Average UF increased from 283 ± 147 to 575 ± 135 mL (p = 0.019 by paired t test). On the other hand, there was no significant difference in the average dialysate K t/V before and after TVP treatment. Serum sodium, AMA, and serum albumin levels were not statistically different before and after TVP treatment. The urine and serum OSM ratio of effective cases before TVP treatment was higher than that of ineffective cases (p = 0.024 by unpaired t test).

Our results indicate that TVP is useful for patients on continuous ambulatory PD who have oliguria and high urine osmolarity. Furthermore, we can reduce PD volume to maintain their nutritional status.