Fildena drug is primarily the best pill for people who have ED i.e. the problem of impotence. Fildena is taken 1 hour before intercourse. After taking it, its effect lasts for 4-5 hours. Fildena drug is also found in different potencies. Consult a doctor before taking Fildena vs Viagra drug. Sildenafil acts as the active ingredient in the drug Fildena.