Fildena Professional 100mg is a generic version of Viagra, and like Viagra, it is primarily used to treat erectile dysfunction (ED). The main active ingredient, Sildenafil Citrate , works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which leads to an increase in nitric oxide levels. Nitric oxide helps relax the muscles in the blood vessels of the penis, which allows for increased ...