Administered orally, once daily for 8 weeks

Arterial RI was a measure of vascular resistance using Doppler ultrasound. RI was the ratio of (peak systolic velocity - end diastolic velocity)/peak systolic velocity, and increased as resistance to flow increased. The least squares (LS) mean was estimated from a mixed-effects model with repeated measures (MMRM) that included fixed effects for treatment, region, visit, and treatment-by-visit interaction, baseline as a covariate, a random effect of participant within treatment, and an unstructured covariance matrix.

CPI quantified blood flow in a pre-specified region of interest by using color Doppler imaging. CPI was the mean color pixel intensity in the region of interest and scores could range from 0 to 160. An increase in CPI reflected an increase in blood flow. The least squares (LS) mean was estimated from a mixed-effects model with repeated measures (MMRM) that included fixed effects for treatment, region, visit, and treatment-by-visit interaction, baseline as a covariate, a random effect of participant within treatment, and an unstructured covariance matrix.

Total of all reporting groups

Investigator-reported etiology of a participant's ED at baseline. ED was defined as a consistent change in the quality of an erection adversely affecting the participant's satisfaction with sexual intercourse. ED etiology (psychogenic, organic, mixed, or unknown) was based on the investigator's opinion. Only randomized participants with ED at baseline were summarized (Placebo N=33 and Tadalafil N=29).

Investigator-reported severity of a participant's ED at baseline. ED was defined as a consistent change in the quality of an erection adversely affecting the participant's satisfaction with sexual intercourse. The severity (mild, moderate, or severe) of ED was based on the investigator's opinion. Only randomized participants with ED at baseline were summarized (Placebo N=33 and Tadalafil N=29).

Participant-reported ED duration (<1 year or ≥1 year). ED was defined as a consistent change in the quality of an erection adversely affecting the participant's satisfaction with sexual intercourse. Only randomized participants with ED at baseline, who had a baseline ED duration assessment, were summarized (Placebo N=32 and Tadalafil N=29).

Body mass index was an estimate of body fat based on body weight divided by height squared.

LUTS was reported as moderate [International Prostate Symptom Score (IPSS) Total Score <20] or severe (IPSS Total Score ≥20). The IPSS Total Score was the sum of Questions 1 through 7 in the IPSS questionnaire. Each question was scored from 0 (none/no symptoms) to 5 (frequent symptoms) for an IPSS Total Score ranging from 0 to 35 points; higher numerical scores from the IPSS questionnaire represented a greater severity of symptoms.

Qmax was measured in mL/sec using a standard, calibrated flowmeter. Only randomized participants with a valid uroflowmetry assessment at baseline were summarized (Placebo N=48 and Tadalafil N=45).

Postvoid residual volume of urine measured by ultrasound.

Tadalafil: 5-milligram (mg) tablet administered orally, once daily for 8 weeks.

Arterial RI was a measure of vascular resistance using Doppler ultrasound. RI was the ratio of (peak systolic velocity - end diastolic velocity)/peak systolic velocity, and increased as resistance to flow increased. The least squares (LS) mean was estimated from a mixed-effects model with repeated measures (MMRM) that included fixed effects for treatment, region, visit, and treatment-by-visit interaction, baseline as a covariate, a random effect of participant within treatment, and an unstructured covariance matrix.

Randomized participants who received at least 1 dose of study medication, had non-missing data (arterial RI in the prostate transition zone) at baseline, and a post-baseline visit.

Arterial RI was a measure of vascular resistance using Doppler ultrasound. RI was the ratio of (peak systolic velocity - end diastolic velocity)/peak systolic velocity, and increased as resistance to flow increased. The least squares (LS) mean was estimated from a mixed-effects model with repeated measures (MMRM) that included fixed effects for treatment, region, visit, and treatment-by-visit interaction, baseline as a covariate, a random effect of participant within treatment, and an unstructured covariance matrix.

Randomized participants who received at least 1 dose of study medication.

CPI quantified blood flow in a pre-specified region of interest by using color Doppler imaging. CPI was the mean color pixel intensity in the region of interest and scores could range from 0 to 160. An increase in CPI reflected an increase in blood flow. The least squares (LS) mean was estimated from a mixed-effects model with repeated measures (MMRM) that included fixed effects for treatment, region, visit, and treatment-by-visit interaction, baseline as a covariate, a random effect of participant within treatment, and an unstructured covariance matrix.

Randomized participants who received at least 1 dose of study medication.

Tadalafil: 5-milligram (mg) tablet administered orally, once daily for 8 weeks.

The p-value associated with the LS mean difference of change from baseline to Week 4 in bladder neck RI was tested at a significance level of 0.05 with no adjustments for multiplicity.

The p-value associated with the LS mean difference of change from baseline to Week 8 in bladder neck RI was tested at a significance level of 0.05 with no adjustments for multiplicity.

The p-value associated with the LS mean difference of change from baseline to Week 4 in the prostate peripheral zone CPI was tested at a significance level of 0.05 with no adjustments for multiplicity.

The p-value associated with the LS mean difference of change from baseline to Week 8 in the prostate peripheral zone CPI was tested at a significance level of 0.05 with no adjustments for multiplicity.

The p-value associated with the LS mean difference of change from baseline to Week 4 in the bladder neck CPI was tested at a significance level of 0.05 with no adjustments for multiplicity.

The p-value associated with the LS mean difference of change from baseline to Week 8 in the bladder neck CPI was tested at a significance level of 0.05 with no adjustments for multiplicity.