On-demand IC351 (Cialis) enhances erectile function in patients with erectile dysfunction

Int J Impot Res. 2001 Feb;13(1):2-9. doi: 10.1038/sj.ijir.3900631.


IC351 (Cialis) is a selective inhibitor of PDE5. The efficacy and safety of on-demand dosing of IC351 in men with erectile dysfunction was assessed in a multicenter, double-blind, placebo-controlled study. One hundred seventy-nine men (mean age: 56 y) were randomized to receive placebo or IC351 at doses of 2, 5, 10 or 25 mg, taken on demand over a 3-week period. The primary endpoints were change from baseline in responses to Questions 3 (Q3) and 4 (Q4) of the International Index of Erectile Function (IIEF). IC351 significantly improved IIEF Q3 scores at all doses vs placebo (P < or =0.003). IC351 also significantly improved IIEF Q4 scores in all but the 2 mg group (P < or =0.0003). No significant changes in laboratory values, ECGs, or blood pressure were observed. The most common adverse events were headache and dyspepsia. The conclusion of this study was that on-demand IC351 at doses up to 25 mg was well tolerated and significantly improved erectile function.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Carbolines
  • Coitus
  • Double-Blind Method
  • Erectile Dysfunction / drug therapy*
  • Humans
  • Male
  • Middle Aged
  • Penile Erection / drug effects
  • Phosphodiesterase Inhibitors / administration & dosage*
  • Phosphodiesterase Inhibitors / adverse effects
  • Phosphodiesterase Inhibitors / therapeutic use
  • Placebos
  • Tadalafil


  • Carbolines
  • Phosphodiesterase Inhibitors
  • Placebos
  • Tadalafil