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.
BACKGROUND
After bilateral nerve-sparing radical retropubic prostatectomy (BNSRRP), nocturnal and sexually mediated erections may help to preserve normal erectile function (EF).


OBJECTIVE
To investigate nocturnal penile tumescence and rigidity (NPTR) in a subset (N = 54 men) from a randomized, 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 assessments 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.


METHODS
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 objectively improved nocturnal erections and pharmaceutically unassisted EF.
McCullough
Andrew R
AR
New York University Medical Center-Urology, New York, NY, USA. andy.mccullough@nyumc.org
Levine
Laurence A
LA
Padma-Nathan
Harin
H
D000328:Adult; D000368:Aged; D019540:Area Under Curve; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy* / Q000209:etiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000009:adverse effects; D017060:Patient Satisfaction; D010410:Penile Erection / Q000187:drug effects*; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011468:Prostatectomy / Q000009:adverse effects*; D011471:Prostatic Neoplasms / Q000601:surgery; D011687:Purines / Q000627:therapeutic use; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000627:therapeutic use*; D013997:Time Factors; D016896:Treatment Outcome
D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D000068677:Sildenafil Citrate