Tadalafil in the treatment of erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy: A randomized, double-blind, placebo controlled trial

Purpose: We evaluated the efficacy and safety of tadalafil 20 mg, taken on demand, in men with erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy (BNSRRP). Materials and Methods: This randomized, double-blind, placebo controlled multicenter study consisted of a 4-week treatment-free run-in period (baseline) followed by 12 weeks of treatment. A total of 303 men (mean age 60 years) with preoperative normal erectile function who had undergone a BNSRRP 12 to 48 months before study were randomized (2:1) to tadalafil (201) or placebo (102). The 3 co-primary end points were changes from baseline in the International Index of Erectile Function erectile function domain score, and the percentage of positive responses to Sexual Encounter Profile questions 2 (successful penetration) and 3 (successful intercourse). The Global Assessment Question and the Erectile Dysfunction Inventory of Treatment Satisfaction questionnaire were secondary end points. We defined a priori a subgroup of 201 patients reporting evidence of postoperative tumescence, defined as 50% or greater "yes" responses to Sexual Encounter Profile question 1 (ability to achieve at least some erection) during baseline intercourse attempts and stratified randomization based on this criterion. Results: Patients receiving tadalafil reported greater improvement on all primary and secondary end points (p