Jens-Uwe Stolzenburg, Hitendra R.H. Patel, Daniel Chevallier, Kazimierz Krajka, Carsten Henneges, Ruth Dickson, Francesco Montorsi, Gerald Brock, John P. Mulhall, Hartwig Büttner, Ignacio Moncada, Montorsi, Francesco, Brock, G, Stolzenburg, Ju, Mulhall, J, Moncada, I, Patel, Hrh, Chevallier, D, Krajka, K, Henneges, C, Dickson, R, and Buttner, H.
Background: The potential rehabilitative and protective effect of phosphodiesterase type 5 inhibitors (PDE5-Is) on penile function after nerve-sparing radical prostatectomy (NSRP) remains unclear. Objective: The primary objective was to compare the efficacy of tadalafil 5 mg once daily and tadalafil 20 mg on demand versus placebo taken over 9 mo in improving unassisted erectile function (EF) following NSRP, as measured by the proportion of patients achieving an International Index of Erectile Function-Erectile Function domain (IIEF-EF) score >= 22 after 6-wk drug-free washout (DFW). Secondary measures included IIEF-EF, Sexual Encounter Profile question 3 (SEP-3), and penile length. Design, setting, and participants: Randomised, double-blind, double-dummy, placebocontrolled trial in men = 22, SEP-3, and penile length. Results and limitations: Four hundred twenty-three patients were randomised to tadalafil once daily (n = 139), on demand (n = 143), and placebo (n = 141). The mean age was 57.9 yr of age (standard deviation: 5.58 yr); 20.9%, 16.9%, and 19.1% of patients in the tadalafil once daily, on demand, and placebo groups, respectively, achieved IIEF EF scores >= 22 after DFW; odds ratios for tadalafil once daily and on demand versus placebo were 1.1 (95% confidence interval [CI], 0.6-2.1; p = 0.675) and 0.9 (95% CI, 0.5-1.7; p = 0.704). At the end of double-blind treatment (EDT), least squares (LS) mean IIEF-EF score improvement significantly exceeded the minimally clinically important difference (MCID: DIIEF-EF >= 4) in both tadalafil groups; for SEP-3 (MCID >= 23%), this was the case for tadalafil once daily only. Treatment effects versus placebo were significant for tadalafil once daily only (IIEF-EF: p = 0.016; SEP-3: p = 0.019). In all groups, IIEF-EF and SEP-3 decreased during DFW but continued to improve during open-label treatment. At month 9 (EDT), penile length loss was significantly reduced versus placebo in the tadalafil once daily group only (LS mean difference 4.1 mm; 95% CI, 0.4-7.8; p = 0.032). Conclusions: Tadalafil once daily was most effective on drug-assisted EF in men with erectile dysfunction following NSRP, and data suggest a potential role for tadalafil once daily provided early after surgery in contributing to the recovery of EF after prostatectomy and possibly protecting from penile structural changes. Unassisted EF was not improved after cessation of active therapy for 9 mo. (C) 2013 Published by Elsevier B.V. on behalf of European Association of Urology.