title: The ENDOTRIAL study: a spontaneous, open-label, randomized, multicenter, crossover study on the efficacy of sildenafil, tadalafil, and vardenafil in the treatment of erectile dysfunction.
abstract: BACKGROUND
  The three effective, commercially available drugs for the treatment of erectile dysfunction-sildenafil, vardenafil, and tadalafil-inhibit the same substrate, the erectolytic enzyme phosphodiesterase type 5 (PDE5). Although there are pharmacological differences between these three compounds, few comparative studies have been conducted to date.
  
  
  OBJECTIVE
  The aim of this study was to determine the efficacy of sildenafil, tadalafil, and vardenafil in a randomly assigned 8-week fixed regimen.
  
  
  METHODS
  This was a spontaneous, open-label, randomized, multicenter, crossover study where the patients were randomized to receive sildenafil 50 mg, sildenafil 100 mg, tadalafil 20 mg, or vardenafil 20 mg.
  
  
  METHODS
  The primary outcome included the posttreatment analysis of erectile function domains of the abridged International Index of Erectile Function (IIEF5+1). The secondary objectives included the analysis of peak-systolic velocities (PSVs), end-diastolic velocities (EDVs), and resistive index (RI), and the estimate of the percentage of men with normal penile hemodynamic parameters after each treatment.
  
  
  RESULTS
  In all groups of patients taking sildenafil 50 mg, sildenafil 100 mg, tadalafil 20 mg, and vardenafil 20 mg at a frequency reflecting the common treatment regimens in real life, there was a statistically significant baseline-to-end point improvement in subjective perception of erectile function measured by IIEF5+1. When the four groups were compared, the treatments were not different in modifying IIEF5+1 and penile flow parameters. However, the within-group analysis showed that PSV improved in the sildenafil 50 mg group and that PSV together with RI significantly ameliorated in patients receiving 100 mg of sildenafil. Regression analysis confirmed an independent effect of sildenafil on hemodynamic efficacy parameters.
  
  
  CONCLUSIONS
  An overall equivalence was demonstrated in the subjective perception of treatment benefits for all the PDE5i tested. However, sildenafil, in a dose-dependent manner, was the unique PDE5i able to ameliorate some of the penile flow parameters within the 8-week treatment period. These findings should be interpreted conservatively because of the observational nature of the study.
authors: School of Sexology, Department of Experimental Medicine, University of L'Aquila, Coppito, L'Aquila, Italy. emmanuele.jannini@univaq.it
authors: Emmanuele A
authors: EA
authors: Jannini
authors: Andrea M
authors: AM
authors: Isidori
authors: Giovanni Luca
authors: GL
authors: Gravina
authors: Antonio
authors: A
authors: Aversa
authors: Giancarlo
authors: G
authors: Balercia
authors: Massimo
authors: M
authors: Bocchio
authors: Marco
authors: M
authors: Boscaro
authors: Cesare
authors: C
authors: Carani
authors: Giovanni
authors: G
authors: Corona
authors: Andrea
authors: A
authors: Fabbri
authors: Carlo
authors: C
authors: Foresta
authors: Gianni
authors: G
authors: Forti
authors: Sandro
authors: S
authors: Francavilla
authors: Antonio R M
authors: AR
authors: Granata
authors: Mario
authors: M
authors: Maggi
authors: Riccardo
authors: R
authors: Mansani
authors: Pierfrancesco
authors: P
authors: Palego
authors: Giovanni
authors: G
authors: Spera
authors: Mario
authors: M
authors: Vetri
authors: Andrea
authors: A
authors: Lenzi
mesh_terms: D000704:Analysis of Variance; D002243:Carbolines / Q000627:therapeutic use*; D016001:Confidence Intervals; D018592:Cross-Over Studies; D006306:Health Surveys; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use*; D018783:Impotence, Vasculogenic / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D010879:Piperazines / Q000627:therapeutic use*; D011687:Purines / Q000627:therapeutic use; D012306:Risk; D000068677:Sildenafil Citrate; D013223:Statistics as Topic; D013450:Sulfones / Q000627:therapeutic use*; D000068581:Tadalafil; D013997:Time Factors; D014227:Triazines / Q000627:therapeutic use; D000069058:Vardenafil Dihydrochloride
chemical_list: D002243:Carbolines; D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014227:Triazines; D000069058:Vardenafil Dihydrochloride; D000068581:Tadalafil; D000068677:Sildenafil Citrate