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ORIGINAL RESEARCH—PHARMACOTHERAPY FOR ED: Efficacy and Safety of Daily Tadalafil in Men with Erectile Dysfunction Previously Unresponsive to On-demand Tadalafil


Chris McMahon, MD, Australian Centre for Sexual Health, Suite 2–4, 1 A Berry Rd St Leonards Sydney New South Wales 2065, Sydney, Australia. Tel: (61) 2 94373906; Fax: (61) 2 99065900; E-mail:


Conflict of Interest. Dr. McMahon is a paid consultant and/or investigator and/or member of speakers panel for Pfizer, Bayer, GlaxoSmithKline, Eli Lilly, Icos Corp., American Medical Systems, and Johnson & Johnson.


Objective.  To assess the efficacy and safety of daily tadalafil, a potent selective phosphodiesterase 5 inhibitor, for the treatment of erectile dysfunction (ED) in men previously unresponsive to on-demand tadalafil.

Materials and Methods.  A total of 112 men with a mean age of 63 (range 21–79) and moderate to severe ED of various aetiologies were treated with tadalafil, taken on a daily basis at flexible daily doses of 10 and 20 mg for 12 weeks. The three primary outcomes were changes from the pretreatment and on-demand tadalafil baseline in the erectile function domain of the International Index of Erectile Function and the proportion of yes responses to questions 2 and 3 of the Sexual Encounter Profile. Additional efficacy instruments included a Global Assessment Question administered at completion of the study.

Results.  Compared with pretreatment and on-demand tadalafil baseline, daily dosed tadalafil significantly enhanced all efficacy outcome variables. Patients receiving daily tadalafil (10 mg) experienced a significant mean improvement of 12.8 and 8.2 in the International Index of Erectile Function erectile function domain score from baseline (P < 0.001) and from on-demand tadalafil, respectively (P < 0.001). Fifty-eight percent of intercourse attempts (Sexual Encounter Profile question 3) were successfully completed (P < 0.001 vs. pretreatment baseline, P < 0.001 vs. on-demand tadalafil). Improved erections at end point were reported by 69% of men compared with 42% of men with on-demand tadalafil. Daily tadalafil was well tolerated with headache, dyspepsia, and facial flushing as the most frequent adverse events.

Conclusion.  Daily tadalafil (10/20 mg) was effective and well tolerated in this study population and is an effective salvage for previous on-demand tadalafil nonresponders.