A Study in Erectile Dysfunction

Inclusion Criteria

• •At least a 3-month history of erectile dysfunction (ED).
• •Are able to read, understand and provide signed informed consent.
• •Have an International Index of Erectile Function-Erectile Function (IIEF-EF) domain score that is greater than or equal to 17 and less than 26 at screening.
• •Have been taking a maximum dose of sildenafil citrate (100 milligram \[mg\]), vardenafil (20 mg), or tadalafil (20 mg) on as needed basis for at least one month prior to screening.
• •Anticipate having the same female sexual partner during the study who is willing to participate in the required number of sexual intercourse attempts and complete study measures during the study.
• •Agree to make at least four sexual intercourse attempts during both the 4-week as needed run-in period and the 4-week non-drug run-in period.
• •Agree not to use any other erectile dysfunction (ED) treatment, including herbal therapy during the 4-week non-drug, run-in, the double-blind treatment period, the open label period and for 96 hours after the end of the study.
• •Are female and at least 18 years of age at screening.
• •Anticipate having the same male study subject as her sexual partner during the study.
• •Able to read, understand and provide signed informed consent.
• •Agree to make the required number of sexual intercourse attempts with the male sexual study partner during the study.
• •Willing to participate in recording responses to the treatment satisfaction scale.