title: Systematic review of randomised controlled trials of sildenafil (Viagra) in the treatment of male erectile dysfunction.
abstract: BACKGROUND
  Sildenafil (Viagra), a new oral drug for the treatment of erectile dysfunction, was licensed for use across Europe in 1998.
  
  
  OBJECTIVE
  To examine the effectiveness and safety of sildenafil as an oral treatment for erectile dysfunction.
  
  
  METHODS
  Systematic review and meta-analysis.
  
  
  METHODS
  All published or unpublished randomised controlled trials comparing sildenafil with a placebo or alternative therapies.
  
  
  METHODS
  Published studies were sought by computerised searches of electronic databases using the keywords 'sildenafil' and 'Viagra'. A hand search was also done of the British Medical Journal, Lancet, Journal of the American Medical Association, New England Journal of Medicine, British journal of General Practice, Drug, Inpharma and Scrip. An assessment of quality of all identified studies and data extraction was undertaken independently by two researchers. Results were combined in a meta-analysis where appropriate, using RevMan version 3.
  
  
  RESULTS
  Twenty-one trials were identified. All trials showed a statistically significant improvement in erectile or sexual function in patients using sildenafil compared with a placebo. A meta-analysis of 16 trials reporting a global efficacy response showed that men were 3.57 (95% CI = 2.93-4.43) times as likely to have improved erections on sildenafil compared with those on a placebo. The number needed to treat to have one man with improved erections was two. The drug has a relatively safe side-effect profile.
  
  
  CONCLUSIONS
  Available research shows that sildenafil is an effective treatment for male erectile dysfunction. Many trial participants had some baseline erectile function and it is probable that in clinical practice, where the erectile function tends to be more impaired, the number needed to treat may be higher.
authors.affiliation: Department of Public Health & Epidemiology, Keele University. A.J.Burls@bham.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Burls
authors.forename: L
authors.initials: L
authors.lastname: Gold
authors.forename: W
authors.initials: W
authors.lastname: Clark
mesh_terms: D000328:Adult; D000368:Aged; D017322:Clinical Trials, Phase II as Topic; D017326:Clinical Trials, Phase III as Topic; D048909:Diabetes Complications; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines; D016032:Randomized Controlled Trials as Topic; D000068677:Sildenafil Citrate; D013450:Sulfones; D016896:Treatment Outcome
chemical_list: D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate