A dose-escalation study to assess the efficacy and safety of sildenafil citrate in men with erectile dysfunction

Objective To assess the efficacy and safety of sildenafil citrate (Viagra(R ), Pfizer Inc., USA) in a double-blind, placebo-controlled, dose-escalation study over a period of 26 weeks in men with erectile dysfunction of a broa d spectrum of aetiology. Patients and methods In all, 315 patients from five countries were randomiz ed to receive treatment with placebo (156 men) or sildenafil (159 men). Sig nificant concomitant medical conditions were hypertension (20%), a history of pelvic surgery (19%), diabetes mellitus (15%), and ischaemic heart disea se (10%). Patients randomized to treatment received a starting dose of 25 m g of sildenafil or matching placebo, which could be increased to 50 mg and then to 100 mg of sildenafil, based on efficacy and tolerability. Assessmen ts of efficacy comprised the 15-item International Index of Erectile Functi on (IIEF), including question three (ability to achieve an erection) and qu estion four (ability to maintain an erection), a partner questionnaire, an overall efficacy question, and event-log data. Results After 12 weeks of treatment, 26%, 32% and 42% of patients were taki ng 25, 50 and 100 mg of sildenafil, respectively. A similar distribution of doses was reported after 26 weeks of treatment. Treatment with sildenafil significantly improved the patients' abilities to achieve and maintain an e rection compared with treatment with placebo (P < 0.001). Scores for four o f the five sexual function domains of the IIEF (erectile function, orgasmic function, intercourse satisfaction and overall satisfaction) also improved significantly (P < 0.001). There was a significant improvement in the mean score for the erectile function domain. regardless of the aetiology of ere ctile dysfunction (P < 0.001). After 12 weeks and 26 weeks of treatment, 82 % and 79% of patients receiving sildenafil reported improved erections, com pared with 24% and 23% of patients receiving placebo, respectively (P < 0.0 01). Treatment-related adverse events were mild to moderate and occurred in 27% of patients receiving sildenafil, compared with 8% of patients receivi ng placebo. Conclusion Sildenafil is an effective and well-tolerated treatment for men with erectile dysfunction of a broad spectrum of aetiology.