title: Sildenafil citrate as a medical expulsive therapy for distal ureteric stones: A randomised double-blind placebo-controlled study.
abstract: OBJECTIVE
  To study the effect of sildenafil citrate on spontaneous passage of distal ureteric stones (DUS).
  
  
  METHODS
  This was a randomised double-blinded placebo-controlled study of 100 patients with DUS. Inclusion criteria were: male, age 18-65 years, normal renal function, and a single radiopaque unilateral DUS of 5-10 mm. Patients were randomly allocated into two equal groups, one that received placebo and the other that received 50 mg sildenafil citrate once daily. Both investigators and patients were masked to the type of treatment. Patients self-administered the medication until spontaneous passage of the DUS. In patients where there was uncontrolled pain, fever, an increase in serum creatinine of >1.8 mg/dL, progressive hydronephrosis or no further progress after 4 weeks, a decision was taken for further treatment.
  
  
  RESULTS
  In all, 47 and 49 patients were available for analysis in both the placebo and sildenafil citrate groups; respectively. Both groups were comparable for age and stone characteristics. Spontaneous expulsion occurred in 19 of 47 patients (40.4%) in the placebo group and in 33 of 49 (67.3%) in the sildenafil citrate group (P = 0.014). The mean time to stone expulsion was significantly shorter in the sildenafil citrate group (P < 0.001). A multivariable Cox proportional hazards model showed that receiving sildenafil citrate was the only independent factor that had a significant impact on stone passage with a hazard ratio of 2.7 (95% confidence interval 1.5-4.8; P < 0.001).
  
  
  CONCLUSIONS
  Sildenafil citrate enhances spontaneous passage of 5-10 mm DUS.
authors.affiliation: Urology and Nephrology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Shokeir
authors.affiliation: Urology and Nephrology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Tharwat
authors.affiliation: Urology and Nephrology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt.
authors.forename: Ahmed Elhussein
authors.initials: AE
authors.lastname: Abolazm
authors.affiliation: Urology and Nephrology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Harraz
keywords: DUS, distal ureteric stones; ESWL, extracorporeal shockwave lithotripsy; KUB, plain abdominal radiograph of the kidneys, ureters and bladder; MET, medical expulsive therapy; Medical expulsive therapy; NCCT, noncontrast computed tomography; NO, nitric oxide; PDE5, phosphodiesterase 5; Phosphodiesterase inhibitors; RCT, randomised controlled trial; Sildenafil citrate; Stone; Ureter; cAMP, cyclic adenosine monophosphate; cGMP, cyclic guanosine monophosphate