Psychological and Interpersonal Outcomes in Men Receiving Sildenafil Citrate and Tadalafil for the Treatment of Erectile Dysfunction in an Open-Label, Crossover Study.

Psychological and Interpersonal Outcomes in Men Receiving Sildenafil Citrate and Tadalafil for the Treatment of Erectile Dysfunction in an Open-Label, Crossover Study, John Dean, Department of Urology, United Kingdom; Geoff Hackett, Good Hope Hospital, United Kingdom; Vincenzo Gentile, Dipartimento di Urologia; Furio Farina, Department of Andrology; Yanli Zhao, Mark Harrison, and Anthony Beardsworth, Eli Lilly and Company 

The Psychological and Interpersonal Relationship Scales (PAIRS) is a self-report measure used to assess psychosocial factors associated with erectile dysfunction (ED) and its treatment. We used PAIRS to compare sexual self-confidence, spontaneity, and time concerns in an open-label, crossover study of sildenafil citrate (sildenafil) and tadalafil in men with ED who were naive to phosphodiesterase 5 (PDE5) inhibitors. After a 4-week baseline assessment, men with ED (N = 367; mean age = 54 years) and no prior history of treatment with PDE5 inhibitors were randomized to sildenafil for 12 weeks followed by tadalafil for 12 weeks, or vice versa. Medications were taken as needed during the 12-week period, which included an 8-week dose-optimization phase and 4-week assessment phase. During the dose-optimization phase, patients started with 25 or 50 mg sildenafil or 10 mg tadalafil (per the SPC) and could titrate up and down to find their optimum dose of 25, 50, or 100 mg sildenafil or 10 or 20 mg tadalafil. Men completing both 12-week periods chose which treatment to continue during an 8-week extension (primary objective). PAIRS (secondary objective) was measured at baseline and after each 12-week treatment period. Of 294 men completing both treatment periods, 29% chose sildenafil and 71% chose tadalafil for the 8-week extension. Treatment choice for the extension phase was not affected by treatment sequence, ED severity, or etiology, age, or dosage. Sildenafil and tadalafil were well-tolerated, with 11 participants discontinuing for an adverse event and 3 for lack of efficacy. Overall, men with ED reported significantly greater sexual self-confidence and spontaneity and significantly less sexual time concerns when treated with tadalafil compared with sildenafil. The differences in PAIRS domains may help explain why more men chose tadalafil compared to sildenafil for treatment extension.