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 .
Sildenafil citrate after radical retropubic prostatectomy.
PURPOSE Erectile dysfunction continues to be a significant problem for men after radical retropubic prostatectomy  despite nerve sparing techniques . Sildenafil citrate ( Viagra ) has proved effective for erectile dysfunction in many men . We determine the efficacy of sildenafil in men with erectile dysfunction after radical retropubic prostatectomy  and examine variables that may impact the response to treatment . MATERIAL S AND METHODS A total of 84 men were prescribed sildenafil after radical retropubic prostatectomy  and asked to complete a series of question naires , including the International Index of Erectile Function ( IIEF ) , on erectile function before and after sildenafil administration . The importance of factors , such as patient age , time since surgery , degree of cavernous nerve sparing , preoperative prostate specific antigen , Gleason score , clinical and pathological stage , and baseline postoperative erectile function , was examined . RESULTS Of the 84 patients 45 ( 53 % ) had improved erections and 34 ( 40 % ) had improved ability for intercourse while taking sildenafil .  Mean IIEF score for the erectile function domain increased from 9 to 14 ( p < 0.001 ) . Orgasmic function ( p = 0.004 ) and intercourse satisfaction ( p = 0.009 ) also significantly improved . The degree of nerve sparing and baseline postoperative erectile dysfunction had a significant impact on the ability of sildenafil to improve erectile function ( p = 0.010 and p < 0.001 , respectively ) and total IIEF question naire responses ( p = 0.031 and p < 0.001 , respectively ) . Age and pathological stage also appeared to have a significant effect . CONCLUSIONS Sildenafil improved erectile function and the ability to have intercourse in more than half of men after radical retropubic prostatectomy . Baseline postoperative erectile function , which is dependent on the degree of nerve sparing technique , significantly impacts the likelihood that patients will respond to sildenafil
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 .