Fildena 50 is a medication used to treat erectile dysfunction (ED) in men. It contains the active ingredient Sildenafil citrate, which is a phosphodiesterase type 5 (PDE5) inhibitor. Sildenafil citrate works by increasing blood flow to the penis during sexual stimulation, facilitating the achievement and maintenance of an erection. Sildenafil citrate inhibits the action of PDE5, leading to the relaxation of blood vessels in the penis. This increased blood flow helps men with ED to attain and sustain an erection when sexually stimulated.