Time/duration effectiveness of sildenafil versus tadalafil in the treatment of erectile dysfunction in male spinal cord-injured patients

Study design: A randomized, blinded, crossover clinical trial comparing sildenafil versus tadalafil for erectile dysfunction (ED) in male spinal cord-injured (SCI) patients. Objectives: To compare the safety, time/duration effectiveness, and the impact on the quality of life (QoL) of tadalafil 10 mg versus sildenafil 50 mg. Setting: Neurourology Section, Careggi Hospital, Florence, Italy. Methods: During a screening (visit 1), a diary card was distributed, in which the subjects assessed, after each attempt at intercourse the quality of their erection, responding (Yes/No) to both Sexual Encounter Profile Questions 2 (SEP2) and 3 (SEP3). The subjects made at least four attempts at intercourse. At visit 2, 15 patients (group 1) were assigned sildenafil and 15 (group 2) started with tadalafil. Responses to baseline International Index of Erectile Function 5 items (IIEF-5), Questions 13-14 (IIEF 15 items) and SEP diary were recorded. Patients attempted intercourse on four separate occasions: within 4 h of taking the first tablet, within 12 h for the second tablet, 24 h for the third, and the fourth from 24 to 36 h. At visit 3, the investigators evaluated the effectiveness with the same measures used at baseline. After a wash-out period, at visit 4, Group 1 was given tadalafil, and Group 2 was given sildenafil. Patients were required to observe the same criteria in taking the four tablets as in visit 2. After 4 weeks (visit 5), we evaluated the patients as we did in visit 3. Results: Overall, 28 patients completed the study. No subjects discontinued the drugs due to drawbacks. Tadalafil allowed a majority of men in this trial to achieve both normal sexual functioning up to 24 h postdosing compared to sildenafil (P<0.01) and improved overall sex life satisfaction as well as sexual relations with partner. Conclusion: Based on these data, tadalafil may have the potential to become an important treatment option for ED in SCI patients. Sponsorship: This study was not sponsored.