Sildenafil acts as the active ingredient in Fildena 50mg. Sildenafil acts as the active ingredient in the drug Fildena 50 Mg. Fildena 50mg is taken 1 hour before intercourse, the effect of which lasts for 4-5 hours. Consult a doctor before taking Fildena 50 Mg. Fildena 50 is a widely used drug, if you are also suffering from this type of problem, get it resolved as soon as possible. Fildena 50 is a popular drug that can easily solve the problem of impotence for millions of people around the world.