As Fildena Double 200 mg is a higher dosage, it may have an increased risk of potential side effects compared to lower doses. Common side effects may include headache, flushing, indigestion, muscle aches, and back pain. Serious side effects are rare but may include sudden vision or hearing loss, chest pain, or priapism (a prolonged and painful erection). If you experience any severe or persistent side effects, seek medical attention immediately.