Experimental data support the concept of cavernosal damage and suggest a protective role for daily dosage of a PDE5-I ; however , similar data have not yet been replicated in humans .
Penile rehabilitation programs are common in clinical practice , but there is no definitive evidence to support their use or the best treatment strategy .
PDE5-Is are efficacious and safe in young patients with normal preoperative erectile function who have undergone bilateral nerve-sparing radical prostatectomy .
On-dem and use of a PDE5-I may be at least as efficacious as daily use .
PDE5-I use in penile rehabilitation programs is not supported by rigorous level 1 evidence -based medicine .
PDE5-Is are an efficacious and safe treatment for post-RP ED in properly selected patients .
The experimental results on the protective role of daily dosages of PDE5-Is , while robust , have not been replicated in humans .
CONTEXT  Erectile dysfunction ( ED ) after radical prostatectomy ( RP ) has a significant negative impact on a patient 's health-related quality of life .
Phosphodiesterase type 5 inhibitors ( PDE5-Is ) have recently been utilized not only as a treatment of ED in this population but also as a preventive strategy in penile rehabilitation programs .
OBJECTIVE To eluci date the pathophysiologic mechanisms of post-RP ED , to assess the need for rehabilitation following surgery , and to analyze the basic scientific evidence and clinical applications of PDE5-Is for the prevention and treatment of ED .
EVIDENCE SYNTHESIS Post-RP ED has many factors .
Cavernosal nerve injury induces pro-apoptotic factors ( ie , loss of smooth muscle ) and pro-fibrotic factors ( ie , an increase in collagen ) within the corpora cavernosa .
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 dem and , in men with erectile dysfunction following bilateral nerve sparing radical retropubic prostatectomy ( BNSRRP ) . MATERIAL S AND METHODS This r and omized , 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 r and omized ( 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 question naire 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 r and omization based on this criterion . RESULTS Patients receiving tadalafil reported greater improvement on all primary and secondary end points ( p < 0.001 ) compared to placebo . For all r and omized patients and for the subgroup with evidence of postoperative tumescence , the mean International Index of Erectile Function erectile function domain score increased for patients receiving tadalafil ( mean + /- SEM 5.3 + /- 0.5 and 5.9 + /- 0.7 , respectively , p < 0.001 vs placebo for both ) . For all r and omized patients who received tadalafil , the mean percentage of successful penetration attempts was 54 % and the mean percentage of successful intercourse attempts was 41 % . For the subgroup with evidence of postoperative tumescence these values were 69 % and 52 % , respectively . Of all patients r and omized to tadalafil 62 % and of the subgroup patients r and omized to tadalafil 71 % reported improved erections . Patients receiving tadalafil reported greater treatment satisfaction on the Erectile Dysfunction Inventory of Treatment Satisfaction than those receiving placebo .  Headache ( 21 % ) , dyspepsia ( 13 % ) and myalgia ( 7 % ) were the most commonly reported adverse events . CONCLUSIONS Tadalafil 20 mg , taken on-dem and , was an efficacious and well tolerated treatment for erectile dysfunction following BNSRRP
Experimental data support the concept of cavernosal damage and suggest a protective role for daily dosage of a PDE5-I ; however , similar data have not yet been replicated in humans .
Penile rehabilitation programs are common in clinical practice , but there is no definitive evidence to support their use or the best treatment strategy .
PDE5-Is are efficacious and safe in young patients with normal preoperative erectile function who have undergone bilateral nerve-sparing radical prostatectomy .
On-dem and use of a PDE5-I may be at least as efficacious as daily use .
PDE5-I use in penile rehabilitation programs is not supported by rigorous level 1 evidence -based medicine .
PDE5-Is are an efficacious and safe treatment for post-RP ED in properly selected patients .
The experimental results on the protective role of daily dosages of PDE5-Is , while robust , have not been replicated in humans .
CONTEXT  Erectile dysfunction ( ED ) after radical prostatectomy ( RP ) has a significant negative impact on a patient 's health-related quality of life .
Phosphodiesterase type 5 inhibitors ( PDE5-Is ) have recently been utilized not only as a treatment of ED in this population but also as a preventive strategy in penile rehabilitation programs .
OBJECTIVE To eluci date the pathophysiologic mechanisms of post-RP ED , to assess the need for rehabilitation following surgery , and to analyze the basic scientific evidence and clinical applications of PDE5-Is for the prevention and treatment of ED .
EVIDENCE SYNTHESIS Post-RP ED has many factors .
Cavernosal nerve injury induces pro-apoptotic factors ( ie , loss of smooth muscle ) and pro-fibrotic factors ( ie , an increase in collagen ) within the corpora cavernosa .