This meta-analysis involved studies on a total of 3,361 men who had severe erectile dysfunction (ED). Of this group, 60% involved males with organic ED, 15% had psychogenic problems, and 25% had mixed difficulties. Data were merged from 10 double-blind, placebo-controlled, fixed dose or flexible dose studies.

Over an 8-week period, patients took sildenafil or placebo, as needed, 1 hour prior to sexual activity. The frequency of penetration and the frequency of maintained erections was assessed at baseline and at week 8 using the 15-item self-administered International Index of Erectile Function. Responses were from 0 (did not attempt intercourse) or 1 (almost never/never) to 5 (almost always/always). Severe ED was defined as a baseline score of 0 or 1.

In this analysis, responders were defined as patients who had a score greater than 4 or those whose final score increased by greater than 1. Of 819 men on sildenafil, 377 (46%) had a score greater than 4 on penetration and 393 (48%) had a score greater than 4 on maintaining an erection. Placebo responders averaged 8%. Responders who had a final score increase greater than 1 averaged from 71% to 73%.

According to the investigator, the results of this meta- analysis of sildenafil at 50 and 100 mg doses show it is effective in men with severe ED.