Fildena 50  belongs to the class of medications known as PDE-5 blockers. It prevents the breakdown of cGMP by blocking the activity of PDE-5 enzymes. Nitric oxide (NO) is released when a person is sensually aroused, and the NO that is released results in the production of cGMP. The male genital area accumulates too much cGMP, which causes the penile arteries to relax and widen. This results in a stronger or longer-lasting erection by increasing the blood flow to the male genital area.