Sildenafil Citrate, also known as Fildena CT 100 mg, is a drug used to treat erectile dysfunction in men. It works by relaxing the muscles of the blood vessels and increasing the flow of blood to the sexual organ. Sildenafil Citrate is effective if taken 30 minutes to 1 hour before sexual intercourse. It can also be taken before or after eating. The effects of this drug last for 4-6 hours. You should take this medicine as directed by your doctor.