A Study in Patients With Erectile Dysfunction

Impact of Tadalafil (LY450190) Once a Day or Tadalafil on Demand Compared to Sildenafil Citrate on Demand on Treatment Discontinuation in Patients With Erectile Dysfunction Who Are naïve to PDE5 Inhibitors

The purpose of this study is to investigate if treatment in erectile dysfunction with a long-acting drug (Tadalafil) taken once a day or taken as needed results in a longer treatment adherence and better long term outcomes (over 24 weeks), compared with a short-acting drug (Sildenafil Citrate) taken as needed.

Inclusion Criteria:

• History of Erectile Dysfunction (ED) of at least 3 months duration.
• Anticipate having the same adult female sexual partner during the study.
• Agree not to use any other treatment for ED and to participate in recording responses to questionnaires and other instruments used in this study.

Exclusion Criteria:

• Previous or current treatment with tadalafil or any other phosphodiesterase type 5 (PDE5) inhibitor.
• ED caused by other primary sexual disorders, history of radical prostatectomy or other pelvic surgery with subsequent failure to achieve any erection, or history of penile implant or clinically significant penile deformity.
• ED caused by untreated or inadequately treated endocrine disease.
• Current treatment with doxazosin, nitrates, cancer chemotherapy, or anti-androgens.
• Severe renal or hepatic impairment, history of malignant hypertension.
• Presence or history of specific heart conditions.