Efficacy and safety of oral sildenafil in the treatment of erectile dysfunction: a double-blind, placebo-controlled study of 329 patients. Sildenafil Study Group

Int J Clin Pract. 1998 Sep;52(6):375-9.


The efficacy and safety of oral sildenafil citrate for the treatment of erectile dysfunction (ED) were assessed in a 12-week placebo-controlled study. Men with ED of organic, psychogenic, or mixed aetiology were randomised to placebo (n = 166) or 50 mg sildenafil (n = 163), with adjustment to 100 mg or 25 mg based on efficacy and tolerability. Efficacy assessments included a global efficacy question, event log data, and an optional partner questionnaire. At the end of the study, improved erections were reported by 74% of patients receiving sildenafil versus 16% for placebo (p < 0.0001). In the final 4 weeks of treatment, 65% of all attempts at sexual intercourse were successful for all patients (responders and non-responders) receiving sildenafil versus 20% for placebo (p < 0.001). The mean number of successful attempts per month was 5.9 for patients receiving sildenafil versus 1.5 for those receiving placebo (p < 0.0001). The most common adverse events--headache, flushing, and dyspepsia--were generally mild to moderate in nature and rarely (< 1%) a reason for discontinuation of treatment. Oral sildenafil is an effective, reliable and well-tolerated treatment for ED of organic, psychogenic or mixed aetiology.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Adult
  • Aged
  • Aged, 80 and over
  • Coitus
  • Erectile Dysfunction / drug therapy*
  • Humans
  • Male
  • Middle Aged
  • Phosphodiesterase Inhibitors / administration & dosage*
  • Piperazines / administration & dosage*
  • Purines
  • Sildenafil Citrate
  • Sulfones
  • Surveys and Questionnaires
  • Treatment Outcome


  • Phosphodiesterase Inhibitors
  • Piperazines
  • Purines
  • Sulfones
  • Sildenafil Citrate