ABSTRACT
AIM: To compare Sexual Self-Confidence and other treatment outcomes following 8 weeks of treatment with tadalafil 5 mg once a day (OaD) vs. tadalafil 20 mg or sildenafil 100 mg as needed (pro re nata [PRN]) in patients with erectile dysfunction (ED). METHODS: A randomized, open-label, crossover study in men ≥18 years of age with history of ED and satisfactory response to current oral phosphodiesterase 5 (PDE5) inhibitor PRN. Data were analyzed with a mixed effects model for crossover design. MAIN OUTCOME MEASURES: The primary outcome measure was the Sexual Self-Confidence domain of the Psychological and Interpersonal Relationship Scales (PAIRS) between tadalafil OaD and sildenafil PRN. SECONDARY OUTCOMES INCLUDED: Time Concerns and Spontaneity domains of PAIRS, and the Self-Esteem and Relationship (SEAR) scale. RESULTS: Men naive to tadalafil OaD were enrolled (N = 378), with 61-69% prior PDE5 inhibitor use. There were improvements in all PAIRS domains from baseline when comparing tadalafil OaD and PRN with sildenafil PRN (P < 0.001). The Sexual Self-Confidence domain improved from baseline and was 0.50 ± 0.78 following tadalafil OaD, 0.5 ± 0.72 for tadalafil PRN, and 0.39 ± 0.67 for sildenafil PRN. The difference in least-squares mean was 0.12 ± 0.04 (confidence interval [CI] = 0.04, 0.19; P = 0.001) between tadalafil OaD and sildenafil PRN and 0.01 ± 0.04 (CI = -0.06, 0.08; P = 0.872) between tadalafil OaD and tadalafil PRN. The Time Concerns domain score was lower with tadalafil OaD than tadalafil PRN (P < 0.001). There were no differences in SEAR scores between treatments. CONCLUSIONS: Tadalafil OaD and tadalafil PRN compared with sildenafil PRN demonstrated greater improvements in Sexual Self-Confidence, Time Concerns, and Spontaneity. There was no significant difference in Sexual Self-Confidence between tadalafil OaD and tadalafil PRN. Changes in SEAR, the erectile function domain of the International Index of Erectile Function, and the Erectile Dysfunction Inventory of Treatment Satisfaction scores from baseline to end point were similar.