Diabetes mellitus and erectile dysfunction in Japanese men

Background: Diabetes mellitus (DM) is frequently associated with difficult-to-treat erectile dysfunction (ED). We performed two investigations about treatment for DM associated with ED in Japanese. The first investigation was to compare efficacy between Vardenafil 20 mg and 10 mg, whereas the second investigation was to observe whether Vardenafil allows successful intercourse initiated rapidly after dosing in Japanese patients with DM and ED. Methods: In the first investigation, 954 patients were recruited and randomly assigned into three groups, i.e., placebo group, valdenafil 10mg group and valdenafil 20mg group. Patients were instructed to take a single dose 1 h prior to sexual intercourse and not to take more than one dose per day with at least 24 h elapsing between doses. In the second investigation, a total of 778 patients were randomized to treatment, and 778 were included in the intent-to-treat analysis of efficacy. Patients received vardenafil 10 mg, 20 mg, or placebo, and were instructed to start sexual activity an hour after dosing. Results: First investigation revealed that Vardenafil 20 mg demonstrated superior efficacy to that of 10mg. The difference on efficacy between 10mg and 20mg was more evident in severe ED patients (base-line IIEF EF domain score <11). Second investigation revealed that Vardenafil allowed for successful completion of sexual activity irrespective of the time when men chose to initiate insertion after drug dosing, with treatment differences over placebo noted from as early as 15 min. Conclusions: Vardenafil 20mg demonstrated superior efficacy compared to 10mg, suggesting incremental clinical benefit in using the higher dose in this difficult-to-treat population in Japanese men with DM and ED. In addition, early onset of activity with vardenafil is also achievable in Japanese ED patients with DM.