Fildena 100 is a medication used to treat erectile dysfunction, containing 100 mg of sildenafil citrate. It works by increasing blood flow to the penis, helping to achieve and maintain an erection when sexually stimulated.. It's important to take it as prescribed by a healthcare professional and to be aware of potential side effects, such as headaches, flushing, or digestive issues. Always consult with a doctor before starting any new medication, especially for ED.