fildena 150 mg is a prescription drug used to treat erectile dysfunction (ED) in men. It contains an active ingredient called sildenafil citrate, which belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. Take the medicine 1 hour or 30 minutes before you engage in sexual activity. Works in erection for a long time. Sildenafil is a popular drug.