Causes of on-demand sildenafil failure and rechallenging treatment

Objective To assess the causes of sildenafil failure and the feasibility of successfully rechallenging non-responding patients. Methods A total of 126 consecutive erectile dysfunction (ED) patients from Jan 2009 to Dec 2009 who claimed poor response to sildenafil (sildenafil 100 mg on demand, at lease 4 epiodes) were enrolled into the study. All patients received sexual reeducation and were treated with sildenafil, taken on a daily dose of 50 mg for 4 weeks. The International Index of Erectile Function-5 (IIEF-5), Rigiscan, serum testosterone or penile Doppler were used to evaluate ED and the cause of on-demand sildenafil failure. End point efficacy of rechallenging was evaluated using the IIEF-5 and the sexual encounter profile (SEP) 'Were you able to insert your penis into your partner's vagina?' and 'Did your erection last long enough to achieve successful intercourse?'. Results The recruited patients comprised of 41 cases with psychological ED, 39 cases with hypogonadism ED, 28 cases with diabetes mellitus ED and 18 cases with vascular ED. Compared with pretreatment and on-demand sildenafil baseline, daily administration of sildenafil significantly enhanced all efficacy outcome variables. The IIEF-5 was significantly improved after daily sildenafil (12.3 ± 2.9 vs18. 8±4.4, P＜0.01), 78 patients responded to daily sildenafil. The overall salvage rate was 61.9%(78/126). Conclusions Sexual reeducation and daily administration of sildenafil may be able to salvage many patients with ED who were sildenafil non-responders. Key words: Erectile dysfunction;  Sildenafil;  Medical fatility