- Included subjects were 18 years of age or older
- A clinical diagnosis of erectile dysfunction
- Known responders to either 100 mg sildenafil or 20 mg tadalafil.
- Excluded were subjects who were unable to achieve penile rigidity of greater than or
equal to 20% at the base of the penis that was sustained for at least 3 minutes
- Subjects who are able to achieve penile rigidity of greater than or equal to 60% at
the base of the penis that was sustained for for at least 2 minutes or subjects who
are able to achieve penile rigidity of greater than or equal to 80% at the base of the
penis that is sustained for for at least 1 minute measured by Rigiscan®, at screening
with no therapy, within 60 minutes following visual sexual stimulation
- Subjects currently using any commercially available treatments for erectile
dysfunction
- Subjects on nitrates.