Efficacy and safety of combination of tadalafil and aspirin versus tadalafil or aspirin alone in patients with vascular erectile dysfunction: a comparative randomized prospective study

Purpose We aimed to investigate the efficacy and safety of tadalafil, aspirin, and tadalafil + aspirin combination therapy in vascular erectile dysfunction (VED). Methods A total of 336 patients were randomly divided into four groups (group 1, aspirin 100 mg/day, 126 patients; group 2, tadalafil 5 mg/day, 72 patients; group 3, tadalafil 5 mg + aspirin 100 mg, 72 patients; group 4, placebo, 66 patients). In all groups, the changes from baseline to end point in erectile function scores on the International Index of Erectile Function (IIEF-EF) and the number of patients who answered "yes" to questions 2 and 3 of the sexual encounter profile(SEP) were compared statistically. Results The changes in IIEF-EF scores after treatment were 7.2 +/- 4.4, 7.3 +/- 4.3, 7.5 +/- 4.4, and 2.0 +/- 4.6 for group 1 (p < 0.0001), group 2 (p < 0.0001), group 3 (p < 0.0001), and group 4 (p = 0.0204), respectively. The change in SEP-2 ratios after treatment were 36.6%, 36.9%, 41.7%, and 9.4% for group 1 (p < 0.0001), group 2 (p < 0.0001), group 3 (p < 0.0001), and group 4 (p = 0.2925), respectively. The change in SEP-3 ratios after treatment was 46.6%, 49.2%, 53.7%, and 12.5% for group 1 (p < 0.0001), group 2 (p < 0.0001), group 3 (p < 0.0001), and group 4 (p = 0.1456), respectively. In group 2, both the number of patients who reported side effects (p < 0.0001) and stopped using the drug due to side effects (p < 0.05) were significantly higher than the control and others groups. Conclusions Successful results were obtained by tadalafil and aspirin monotherapy and tadalafil + aspirin combination therapy in patients with VED. However, the least side effect was observed in the tadalafil + aspirin group. Aspirin can be used alone in the treatment of patients with VED, or combined with tadalafil to reduce side effects and increase success.