Systematic review of randomised controlled trials of sildenafil (Viagra (R)) in the treatment of male erectile dysfunction

Background: Sildenafil (Viagra(R)), a new oral drug for the treatment of er ectile dysfunction, was licensed for ase across Europe in 1998, Aim: To examine the effectiveness and safety of sildenafil as an oral treat ment for erectile dysfunction. Design of study.. Systematic review, and meta-analysis. Setting: All published or unpublished randomised controlled trials comparin g sildenafil with a placebo or alternative therapies, Method: Published studies were sought by computerised searches of electroni c 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 Ge neral Practice, Drug, Inpharma and Scrip. An assessment of quality of all i dentified studies and data extraction was undertaken independently by two r esearchers, Results were combined in a metaanalysis where appropriate, usin g RevMan version 3. Results. Tweny-one trials were identified. All trials showed a statisticall y significant improvement in erectile or sexual function in patients using sildenafil compared with a placebo. A metaanalysis of 16 trials reporting a global efficacy response showed that men were 3.57 (95% CI = 2.93-4.43) ti mes 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 erec tions was two. The drug has a relatively, safe side-effect profile. Conclusions: Available research shows that sildenafil is an effective treat ment for male erectile dysfunction. Many trial participants had some baseli ne erectile function and it is probable that in clinical practice, where th e erectile function tends to be more impaired, the number needed to treat m ay be higher.