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 .
Return of nocturnal erections and erectile function after bilateral nerve-sparing radical prostatectomy in men treated nightly with sildenafil citrate: subanalysis of a longitudinal randomized double-blind placebo-controlled trial.
INTRODUCTION After bilateral nerve-sparing radical retropubic prostatectomy ( BNSRRP ) , nocturnal and sexually mediated erections may help to preserve normal erectile function ( EF ) . AIM To investigate nocturnal penile tumescence and rigidity ( NPTR ) in a subset ( N = 54 men ) from a r and omized , double-blind trial ( N = 76 ) of nightly sildenafil after BNSRRP . METHODS Inclusion required preoperative " normal " EF ( defined as a combined score of > /=8 for International Index of Erectile Function questions 3 ( penetration ) and 4 ( maintained erection after penetration ) and NPTR testing ( > /=10 continuous minutes of > /=55 % rigidity [ R > /= 55 % ] at the base ) . Postoperative assessment s were at weeks 4 ( pretreatment ) , 16 , 28 , 40 ( during 36 weeks of nightly prophylaxis : sildenafil 50 mg [ N = 17 ] , 100 mg [ N = 18 ] or placebo [ N = 19 ] ) , and 48 ( after 8 weeks of no erectile dysfunction therapy , when " responders " were delineated by the defined normal EF and a " yes " response to " Over the past 4 weeks , have your erections been good enough for satisfactory sexual activity ? " ) . Base and tip rigidity and tumescence were measured using penile plethysmography . MAIN OUTCOME MEASURES Duration of R > /= 55 % and area under the curves for rigidity and tumescence . RESULTS Postoperatively , rapid profound reduction in nocturnal EF was noted in all groups . There was a gradual dose-dependent improvement in base and tip rigidity in the sildenafil groups but little improvement in the placebo group . Eight weeks after treatment termination ( 48 weeks postoperatively ) , 24 % ( 4/17 ) of 50-mg sildenafil recipients , 33 % ( 6/18 ) of 100-mg sildenafil recipients , and 5 % ( 1/19 ) of placebo recipients were responders . Tip R > /= 55 % was the most discriminating NPTR measure between nonresponders and responders to sildenafil , in whom it regained baseline ( preoperative ) levels ( whereas base R > /= 55 % did not ) . It was most prolonged in responders to sildenafil 100 mg . CONCLUSIONS In our subset analysis , nightly sildenafil for 9 months post-BNSRRP objective ly improved nocturnal erections and pharmaceutically unassisted EF
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 .