Sildenafil improves blood flow to the penis when sexually excited. It does this by causing relaxation of local blood vessels, thus alleviating Erectile Dysfunction, or male impotence.
The benefit of these tablets is that dosing is once weekly, as follows: 10 days before you enter the affected area, the second dose taken 3 days before and then continue to take on the same day of each week whilst there. They are continued for 4 weeks after leaving.