Fildena 100 is a medication used to treat erectile dysfunction (ED). Its active ingredient is sildenafil citrate, which is also found in Viagrasildenafil for treating ED is often 50 mg, but depending on individual response and tolerability, it can be increased to 100 mg. This is the dose found in Fildena 100mg. Common side effects include headaches, flushing, indigestion, nasal congestion, and dizziness. More severe side effects could involve sudden changes in vision or hearing, chest pain, or prolonged erections (priapism).