10mg x 4 weeks, with option to increase to 20mg aat that time if desired

active comparator

The IIEF questionnaire is a validated 15-item instrument that assesses the participant's erectile function over the previous 4 weeks. The IIEF includes 5 domains affecting male sexual function: erectile function, orgasmic function, sexual desire, intercourse satisfaction, and overall satisfaction. Responses to the IIEF were re-coded using a standard coding method, where more positive responses received a higher score. The EF domain score was calculated as the sum of the re-coded scores from questions 1-5 and 15, using last observation carried forward (LOCF). Scores range from 1 (lowest) to 30 (highest). If two or more items in the EF domain were missing, the EF domain score was considered to be missing.

Success rate of insertion was derived from the Sexual Encounter Profile (SEP) Question 2 (SEP-2) of the participant's diary that asked 'Were you able to insert your penis into your partner's vagina?'. Responses were either Yes or No. Patients were instructed to complete diary questions as soon as possible after each sexual attempt, but no later than 24 hours after the attempt. The per-participant overall success rate for insertion was calculated by dividing the number of successful attempts (SEP-2=yes) over 12 weeks by the total number of valid attempts recorded over 12 weeks. If the participant was not able to make any valid attempts in 12 weeks, the participant was non-evaluable. Per-participant success rates were then averaged at the group level to obtain the mean success rate from Weeks 0-12.

Success rate of maintenance was derived from the SEP Question 3 (SEP-3) of the participant's diary that asked 'Did your erection last long enough for you to have successful intercourse?'. Responses were either Yes or No. Participants were instructed to complete diary questions as soon as possible after each sexual attempt, but no later than 24 hours after the attempt. The per-participant overall success rate for maintenance was calculated by dividing the number of successful attempts (SEP-3=yes) over 12 weeks by the total number of valid attempts recorded over 12 weeks. If the participant was not able to make any valid attempts in 12 weeks, the participant was non-evaluable. Per-participant success rates were then averaged at the group level to obtain the mean success rate from Weeks 0-12.

Duration of erection leading to completion of successful intercourse was derived from data recorded in the participant's diary. For each diary entry, the time from erection perceived hard enough for penetration until withdrawal from partner's vagina was measured by stopwatch and recorded in the participant's diary. For diary entries where SEP-3=yes, this recorded duration was used in calculations of a per-participant median duration. For diary entries where SEP-3=no, a duration of 0 was used to calculate the per-participant median. The per-participant median values averaged at the group level to obtain the mean duration of erection leading to completion of successful intercourse as measured by SEP-3.