The primary and active ingredient in Fildena 100 mg tablets is sildenafil. It is a great PDE-5 inhibitor that helps to achieve and sustain a strong, prolonged erection by improving blood flow to the penis. The penis fills with blood and applies pressure to hold the blood there, causing an erection. By clearing clogged arteries and widening blood vessels, sildenafil contributes to a consistent blood flow to the penis. As a result, it enables you to spend more time and have fun with your partner.