The generic substance present in Fildena 100 pills is Sildenafil Citrate. Sildenafil Citrate is a potent phosphodiesterase type 5 (PDE5) inhibitor used to treat erectile dysfunction (ED). It works by increasing blood flow to the penile, facilitating the achievement and maintenance of an erection in response to sexual stimulation. Fildena 100 contains 100 mg of this active ingredient, which is effective in managing ED. This medication is often prescribed as a more affordable alternative to branded ED treatments like Viagra, providing similar benefits and effectiveness.