title: Efficacy and safety of tadalafil 5, 10, and 20 mg in Japanese men with erectile dysfunction: results of a multicenter, randomized, double-blind, placebo-controlled study.
abstract: OBJECTIVE
  To investigate the efficacy and safety of tadalafil, a phosphodiesterase type 5 inhibitor, in Japanese men with erectile dysfunction (ED).
  
  
  METHODS
  This multicenter, randomized, double-blind, placebo-controlled, 12-week study enrolled 343 Japanese men with ED. The men were stratified into those with mild, moderate, or severe ED and then randomly assigned 1:1:1:1 to placebo and 5 mg, 10 mg, and 20 mg tadalafil. Co-primary outcomes were the International Index of Erectile Function erectile function domain score, the percentage of "yes" responses to the Sexual Encounter Profile Diary Questions 2 and 3, and tolerability. Secondary outcomes included the International Index of Erectile Function intercourse satisfaction and overall satisfaction domain scores and the percentage of "yes" responses to a global assessment question.
  
  
  RESULTS
  The least square mean change from baseline was 7.5, 9.1, and 9.4 for 5, 10, and 20 mg tadalafil versus 2.1 for placebo for the International Index of Erectile Function erectile function domain; 28.5, 36.0, and 36.5 for 5, 10, and 20 mg tadalafil versus 8.6 for placebo for Sexual Encounter Profile question 2; and 34.3, 47.3, and 50.8 for 5, 10, and 20 mg tadalafil versus 12.3 for placebo for Sexual Encounter Profile question 3, respectively (P <0.001 for all doses and all measures). Patients taking tadalafil had significantly greater changes from baseline for the intercourse satisfaction and overall satisfaction domains compared with patients taking placebo (P <0.001). Also, 76.5%, 81.4%, and 83.7% of patients taking 5, 10, and 20 mg tadalafil, respectively, reported improved erections (global assessment question) versus 31.4% of patients taking placebo (P <0.001). Most (98%) treatment-emergent adverse events were mild or moderate in severity. One patient (tadalafil 5 mg) discontinued because of an adverse event (ureteral calculus). Of the 343 patients, 302 (88%) completed the study. No deaths were reported.
  
  
  CONCLUSIONS
  All doses of tadalafil studied were efficacious and well tolerated in Japanese men with ED.
authors.affiliation: Department of Urology, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nagao
authors.forename: Yasusuke
authors.initials: Y
authors.lastname: Kimoto
authors.forename: Ken
authors.initials: K
authors.lastname: Marumo
authors.forename: Akira
authors.initials: A
authors.lastname: Tsujimura
authors.forename: G Matthew
authors.initials: GM
authors.lastname: Vail
authors.forename: Steven
authors.initials: S
authors.lastname: Watts
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ishii
authors.forename: Sadao
authors.initials: S
authors.lastname: Kamidono
mesh_terms: D044466:Asian People; D002243:Carbolines / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D000068581:Tadalafil; D016896:Treatment Outcome
chemical_list: D002243:Carbolines; D010726:Phosphodiesterase Inhibitors; D000068581:Tadalafil