Determine Safety and Effectiveness of Tadalafil in Asian Men When Taken as Needed for Getting and Keeping an Erection

A Multinational, Randomized, Double-Blind, Parallel, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Tadalafil Administered "On Demand" to Asian Men With Erectile Dysfunction

Study to determine if tadalafil works better than placebo for Asian men having trouble getting or keeping an erection.

Inclusion Criteria:

• History of erection problems
• Anticipate a monogamous female sexual relationship
• Abstain from other erection treatments at least 4 weeks before first dose and throughout the study
• Must be able to make required sexual intercourse attempts

Exclusion Criteria:

• Other primary sexual disorders
• History of radical prostatectomy or other pelvic surgery that affected being able to have an erection
• History of penile implant or clinically significant penile deformity
• Nitrate use
• Certain heart problems