Fildena 25 mg is a medication containing sildenafil citrate as its active ingredient. It belongs to a class of medications known as phosphodiesterase type 5 (PDE5) inhibitors, commonly used to treat erectile dysfunction (ED).Sildenafil works by relaxing the smooth muscles of the blood vessels in the penis, allowing for increased blood flow when sexually stimulated. This improved blood flow helps to facilitate and maintain an erection during sexual activity.