Daily treatment with tadalafil may result in significantly improved erectile function in men who have an incomplete response to the maximum dose of a phosphodiesterase type 5 (PDE5) inhibitor taken as needed, researchers reported online in the Journal of Sexual Medicine.
Edward D. Kim, MD, of the University of Tennessee Graduate School of Medicine in Knoxville, and colleagues conducted two parallel double-blind studies that enrolled a total of 623 sexually active men with a minimum three-month history of erectile dysfunction (ED) and had been taking the maximum dose of a PDE5 inhibitor. Researchers randomly assigned men to once-daily therapy with tadalafil 2.5-5 mg (207 patients), tadalafil 5 mg (207 patients), or placebo (209 patients) for 12 weeks. Randomization followed a four-week maximum dose PDE5 treatment taken as needed and a four-week non-drug lead period. The main outcome measure was the proportion of patients with a return-to-normal erectile function (International Index of Erectile Function-Erectile Function [IIEF-EF] domain score of 26 or higher) when treated with tadalafil once daily compared with placebo.
At the end of the study, 39% and 40% of the tadalafil 2.5-5 mg group and 5 mg group, respectively, had an IIEF-EF score of 26 or higher compared with 12.1% of the placebo group.