Fildena 100 is a pharmaceutical drug commonly used to treat erectile dysfunction (ED) in men. The active ingredient in Fildena 100 is sildenafil citrate, which belongs to a class of medications known as phosphodiesterase type 5 (PDE5) inhibitors. Sildenafil works by increasing blood flow to the penis during sexual stimulation, enabling a man to achieve and maintain an erection suitable for sexual activity.