Is penile length a factor in treatment of erectile dysfunction with PDE-5 inhibitor?

Erectile dysfunction (ED) is prevalent among men, and several factors can contribute to the failure of ED treatment based on phosphodiesterase-5 (PDE-5) inhibitors. The aim of this study was to investigate the impact of penile size in treatment of ED with PDE-5 inhibitor (tadalafil; 20 mg). We prospectively scrutinized and enrolled in the present study 42 consecutive patients with ED. All measurements of penile length in fully stretched states and the erectile function domain of the International Index of Erectile Function (IIEF-EF) scores were recorded by the same physician (M.S.). Patients were divided into 3 groups according to stretched penile length: small (<25th percentile), normal (25th to 75th percentiles), and large (>75th percentile). Mean IIEF-EF scores were recorded before and after treatment period. Patients received tadalafil (20 mg), taken on demand, a minimum of 6 times. The mean stretched penile length was 13.44 +/- 2.4 cm (range, 9.50-18.00 cm). Overall mean IIEF-EF domain scores were 11.90 +/- 4.78 and 18.67 +/- 6.70 for before and after the treatment period, respectively. Although PDE-5 inhibitor treatment significantly improved all domains of the IIEF-EF scores (P < .05), no statistically significant difference was found among the 3 groups according to mean IIEF-EF domain scores before and after treatment (P > .05). We conclude that penile size is not a factor in treatment of ED patients with a PDE-5 inhibitor.