Fildena 100 Purple pill is a medication used to treat erectile dysfunction (ED) in men. Its active ingredient is sildenafil citrate, which belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors. Sildenafil helps increase blood flow to the penis by relaxing the blood vessels, making it easier to achieve and maintain an erection during sexual stimulation. Fildena 100 mg is typically taken about 30 minutes to 1 hour before sexual activity. The effects can last for up to 4-6 hours. It should be taken only once a day.