title: Results of double-blind placebo-controlled crossover study of sildenafil citrate (Viagra) in women suffering from obstructed voiding or retention associated with the primary disorder of sphincter relaxation (Fowler's Syndrome).
abstract: OBJECTIVE
  Women with the primary disorder of sphincter relaxation find voiding difficult. Studies have identified neuronal nitric oxide synthase in the female urethral sphincter, and nitric oxide donors have been shown to decrease sphincter pressures. The aim of our study was to determine if sildenafil could improve sphincter relaxation and thereby increase flow rates and improve bladder emptying.
  
  
  METHODS
  Twenty women with complete (5), partial retention or obstructed voiding (15) with a maximum flow rate (Qmax) of less than 15 ml/min with an elevated maximal urethral closure pressure (92--age cm H(2)O) and sphincter volume (>1.6 cm(3)) were included in the study. The study was a double-blind, randomised, placebo-control, crossover design, with patients taking sildenafil or placebo, and with measurement of flow rate and residual volume at baseline and after each treatment phase. Voiding diary, quality of life, and International Prostate Symptom Score (IPSS) data were also collected.
  
  
  RESULTS
  No statistical significant difference was seen in any voiding parameters and diaries when sildenafil citrate was compared with placebo. There was a significant mean decrease in IPSS of 3.64 between baseline and the sildenafil phase (p=0.0083), but not when compared with placebo. In the subgroup of women with partial retention and obstructed voiding (15/20), there was a statistically significant increase in Qmax of 4.7 ml/sec (p=0.025) between sildenafil and baseline; however this difference was not seen when compared with placebo.
  
  
  CONCLUSIONS
  This is the first study looking at sildenafil in voiding dysfunction in women. Clinical improvements with sildenafil were not significant when compared with placebo. Sildenafil was not effective as a therapeutic pharmacologic agent in this group of patients.
authors.affiliation: Department of Uro-Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: Soumendra N
authors.initials: SN
authors.lastname: Datta
authors.forename: Rajesh B C
authors.initials: RB
authors.lastname: Kavia
authors.forename: Gwen
authors.initials: G
authors.lastname: Gonzales
authors.forename: Clare J
authors.initials: CJ
authors.lastname: Fowler
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000503:physiopathology; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D013577:Syndrome; D016055:Urinary Retention / Q000188:drug therapy* / Q000209:etiology
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate