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 .
Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy.
OBJECTIVES To determine whether propionyl-L-carnitine ( PLC ) plus acetyl-L-carnitine ( ALC ) improves the effectiveness of sildenafil in restoring sexual potency after bilateral nerve-sparing radical retropubic prostatectomy . METHODS We analyzed the data from 96 patients who had undergone bilateral nerve-sparing radical retropubic prostatectomy : 33 were given placebo ( group 1 ) , 32 used PLC 2 g/day plus ALC 2 g/day plus sildenafil 100 mg when needed ( group 2 ) , and 35 used sildenafil alone ( group 3 ) . The studied variables were sexual function ( assessed through sexual behavior interviews and the International Index of Erectile Function ) , peak systolic velocity and end-diastolic velocity of cavernosal arteries ( assayed by dynamic echo-color Doppler ) , the percentage of patients able to achieve a positive intracavernous injection test , and side effects . RESULTS Placebo proved ineffective and sildenafil and sildenafil plus ALC and PLC proved effective . The International Index of Erectile Function-15 scores of the group 2 patients were significantly greater than those of group 3 in the following domains : erectile function , sexual intercourse satisfaction , orgasm , and general sexual well-being . The drugs did not significantly modify the score in the sexual desire domain or in the peak systolic velocity or end-diastolic velocity of the cavernosal arteries . Sexual behavior interviews revealed that 2 of 29 in group 1 , 28 of 32 in group 2 , and 20 of 39 in group 3 attained satisfactory sexual intercourse ( P < 0.01 ) . Only group 2 had a significantly increased percentage of patients with a positive intracavernous injection test after therapy ( 36.4 % versus 63.6 % ; P < 0.01 ) . ALC plus PLC did not significantly improve the side effects of sildenafil . CONCLUSIONS PLC and ALC proved to be safe and reliable in improving the efficacy of sildenafil in restoring sexual potency after bilateral nerve-sparing radical retropubic prostatectomy
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 .