Conditions: Erectile Dysfunction
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 378
Healthy volunteers: no

Brief summary:
The primary purpose of the study is to help answer whether tadalafil taken once a day can help improve the psychological outcomes (such as sexual self confidence, spontaneity and time concerns) compared to sildenafil taken as needed in patients with erectile dysfunction (ED).

Detailed description:

Arms:
arm 1: Tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks, 1 week washout, sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks, 1 week washout, tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks arm 2: Tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks, 1 week washout, tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks, 1 week washout, sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks arm 3: Sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks, 1 week washout, tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks, 1 week washout, tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks arm 4: Sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks, 1 week washout, tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks, 1 week washout, tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks arm 5: Tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks, 1 week washout, tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks, 1 week washout, sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks arm 6: Tadalafil 20 mg as needed \[T(PRN)\] for 8 weeks, 1 week washout, sildenafil citrate 100 mg as needed \[S(PRN)\] for 8 weeks, 1 week washout, tadalafil 5 mg once a day \[T(OaD)\] for 8 weeks

Interventions: intervention 1: tadalafil once a day [T(OaD)] intervention 2: sildenafil citrate as needed [S(PRN)] intervention 3: tadalafil as needed [T(PRN)]
Intervention descriptions: intervention 1: 5 mg tablet taken once a day (OaD) by mouth for 8 weeks intervention 2: 100 mg tablet taken as needed (PRN) by mouth for 8 weeks intervention 3: 20 mg tablet taken as needed (PRN) by mouth for 8 weeks

Protocol document: