Quality of Erection Study

A Multicenter, Parallel Group Flexible Dose Study With A Double Blind, Randomized, Placebo Controlled Phase And An Open-Label Phase To Evaluate The Quality Of Erections In Men With Erectile Dysfunction Treated With Sildenafil Citrate

The study objective is to evaluate the effect that sildenafil citrate has on the hardness of erections in males with erectile dysfunction, based on subject responses to question 5 on the Event Log (hardness of erection) as measured at the end of double blind treatment (week 6).

Inclusion Criteria:

• Male subjects aged 18-55
• Documented clinical diagnosis of erectile dysfunction confirmed by an IIEF-EF Domain score of less than or equal to 25. (If the subject scores greater than 25 on the IIEF-EF Domain, screening procedures should be terminated.)

Exclusion Criteria:

• Subjects who have been treated with more than 6 doses of sildenafil citrate or any other phosphodiesterase type 5 (PDE-5) inhibitor such as vardenafil or tadalafil for erectile dysfunction [Note: subjects should not have taken any PDE-5 inhibitors within 4 weeks prior to the date of screening]