Efficacy and safety of tadalafil once daily: considerations for the practical application of a daily dosing option.

Objective: To provide clinically relevant information on tadalafil 2.5 or 5 mg once daily for the treatment of erectile dysfunction (ED), by reviewing safety and efficacy study findings. Findings from an integrated analysis of trials of tadalafil 10 and 20 mg as needed are presented to provide context for the daily dosing regime.
Research Design and Methods: Of the three studies that included approved once-daily doses, two were conducted in the general ED population and one in a diabetic ED population. An integrated analysis was performed using 12-week efficacy and safety data from the studies conducted in the general ED population.
Results: In the general ED population, the 12-week mean International Index of Erectile Function (IIEF) erectile function (EF) domain scores increased by 6.2 to an endpoint score of 19.2 and by 8.6 to 21.9 for 2.5 and 5 mg doses, respectively, versus an increase of 1.3 to 14.9 for placebo (p < 0.01). Mean successful intercourse attempts (SEP3) were 50% and 62% for tadalafil 2.5 and 5 mg once daily, respectively, versus 33% for placebo (p < 0.01). These findings were consistent with those for tadalafil as needed. In 1- and 2-year open label extensions of tadalafil 5 mg once daily, efficacy was maintained. In the diabetic ED population, 12-week mean IIEF EF scores increased by 4.8 to 18.3 and 4.5 to 17.2 with tadalafil 2.5 and 5 mg, respectively, versus an increase of 1.3 to 14.7 for placebo (p < 0.01). Mean successful intercourse attempts were more than 40% for each tadalafil dose, versus 28% for placebo (p < 0.01). The profile of treatment-emergent adverse events with tadalafil once daily was similar to that previously reported with as-needed treatment; the most common adverse events with tadalafil (dyspepsia, nasopharyngitis, headaches) were reported in <or=4% of participants.
Conclusions: Findings from the three published studies support a favorable risk-benefit balance for tadalafil 2.5 or 5 mg once daily. Although no direct comparison studies were performed (no head-to-head trials), efficacy and safety findings were consistent with those with tadalafil as needed.