Fildena 120mg is an effective medication for treating erectile dysfunction, but it can have side effects. Common side effects include headaches, dizziness, flushing, and nasal congestion. Some men might experience stomach upset, back pain, or muscle aches. In rare cases, Fildena 120mg can cause more serious side effects like sudden vision loss, hearing problems, or an erection lasting more than four hours (priapism). Always consult your doctor before starting Fildena 120mg to ensure it is safe for you and to discuss potential side effects.