The Efficacy of Tadalafil in Clinical Populations


Ronald W. Lewis, MD, Witherington Chair in Urology, Department of Surgery/Chief of Urology, Medical College of Georgia, 1120 15th Street, Room BA-8412, Augusta, GA 30912, USA. Tel: (706) 721-9977; Fax: (706) 721-2548; E-mail:


Objectives.  To evaluate the efficacy of tadalafil in men with erectile dysfunction (ED) by demographic and ED characteristics, in patients having various comorbid medical conditions, and in patients receiving drug treatment for other medical conditions.

Methods.  This is an analysis of 11 double-blind, placebo-controlled trials with 2,102 men with a broad spectrum of ED etiology and various comorbid medical conditions as participants. The variables analyzed in this report included race, age, body mass index (BMI), ED etiology, ED severity, ED duration, smoking, prior sildenafil use, presence of comorbid conditions (diabetes mellitus, hypertension, cardiovascular disease, hyperlipidemia, depression, benign prostatic hyperplasia), and treatment with antihypertensives or antidepressants. Patients were randomly assigned to receive tadalafil 10 mg (N = 321), tadalafil 20 mg (N = 1,143), or placebo (N = 638). The primary efficacy variables included mean changes from baseline in the erectile function (EF) domain score of the International Index of Erectile Function (IIEF) questionnaire, and the mean per-patient percentage of “yes” responses to the Sexual Encounter Profile (SEP) diary question 3 (SEP3––successful intercourse). The Global Assessment Question 1 (GAQ) was evaluated, as was the percentage of men attaining a normal IIEF EF domain score at end point.

Results.  Patients taking tadalafil 10 mg or 20 mg demonstrated significant improvement (P < 0.005) from baseline to end point on the IIEF EF domain score in all subpopulations analyzed compared with patients receiving placebo. The mean-per-patient percentage of “yes” responses to SEP3 increased significantly in all subpopulations taking tadalafil compared with placebo (P < 0.05). Tadalafil-treated patients had a significantly greater positive response rate on the GAQ in all subpopulations analyzed compared with placebo-treated patients (P < 0.03) except for the tadalafil 10 mg cardiovascular subpopulation (placebo, 46.8%; tadalafil 10 mg, 71.0%; P = 0.127). The percentage of positive responses ranged from 72% to 91% for patients on tadalafil 20 mg and from 52% to 94% for tadalafil 10 mg compared with a range of 20% to 47% for placebo-treated patients.

Conclusions.  Tadalafil was effective in improving erectile function across a wide spectrum of ED patients including patients with various comorbid conditions.