Sildenafil Citrate Can Reduce Pathological Post-obstructive Diuresis in a Rat Model of Bilateral Ureteral Obstruction

Objectives: The current study aimed at assessing the effect of oral sildenafil citrate on postobstructive diuresis and urinary electrolyte changes after resolution of bilateral ureteral obstruction (BUO). Methods: Twenty-eight adult Munich-Wistar male rats were subjected to the surgical-induced BUO for 24 hours. In intervention group (n = 14) sildenafil citrate 200 mg/kg food was administered from the operation day for 72 hours, while in control group (n = 14) no drug was used. Daily urinary volume, urine sodium (mEq/day), potassium (mEq/day), and osmolality (mOsm/kg H2O) were measured on the day before BUO and for 2 days after BUO release. Results: In comparison to the control group, postobstructive diuresis was significantly lower in the sildenafil group (P value < 0.001), while urinary sodium and osmolality were both preserved better in this group (P value < 0.001); however, there were no significant difference in potassium level between the groups (P value = 0.285). Conclusions: Oral sildenafil citrate significantly decreased postobstructive diuresis and preserved urine sodium and osmolality near normal. These 2 effects mean a better preservation of renal function, while preventing pathological postobstructive diuresis.