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Efficacy and Safety of On-Demand Oral Tadalafil in the Treatment of Men with Erectile Dysfunction in Taiwan: A Randomized, Double-Blind, Parallel, Placebo-Controlled Clinical Study


Kuang-Kuo Chen, MD, PhD, Division of Urology, Department of Surgery, Taipei Veterans General Hospital, No. 201, Sec. 2, Shih-Pai Road, Taipei, Taiwan, Republic of China. Tel. (886) 2 28757539, ext. 386; Fax: (886) 2 28757540; E-mail:


Conflict of Interest. Timothy M. Costigan and Jeffrey T. Emmick are employees of Eli Lilly, Indianapolis.


Introduction.  Tadalafil is a phosphodiesterase type 5 inhibitor for the treatment of erectile dysfunction (ED). Past clinical trials have assessed its efficacy and safety in western populations. Tadalafil has not been investigated in a large clinical trial with a South-east Asian population.

Aim.  To assess the efficacy and safety of on-demand tadalafil for the treatment of ED in a 12-week, double-blind, placebo-controlled study in Taiwan.

Methods.  Men with mild to severe ED of various etiologies were randomized to receive placebo, tadalafil 10 mg, or tadalafil 20 mg, taken as needed (maximum once daily). Efficacy assessments included the International Index of Erectile Function, the Sexual Encounter Profile (SEP) diary, and a Global Assessment Question (GAQ).

Results.  Tadalafil significantly improved erectile function compared with placebo (P < 0.005, all measures). At endpoint, the patients receiving tadalafil reported a greater mean per-patient percentage of successful intercourse attempts (SEP question 3: 70.0%, 10 mg; 78.0%, 20 mg) than placebo-treated patients (42.8%) and a greater proportion of improved erections (GAQ: 92.3% and 84.6% vs. 54.5%). Most treatment-emergent adverse events were mild or moderate. The most common adverse events were back pain, dyspepsia, and myalgia.

Conclusions.  Tadalafil was an effective, well-tolerated therapy for men in Taiwan with ED of broad-spectrum severity and etiology.