Sildenafil acts as an active ingredient in the drug Fildena vs Viagra. Sildenafil drug is primarily the best drug for men to use which is the best drug to solve the problem of impotence. Consult your doctor before taking the Fildena drug. At the time of erection, it acts to absorb blood in the uterus. Fildena is found in different strengths such as 25mg of Fildena, 50 mg of Fildena, 100 mg of Fildena150 mg of Fildena, 200mg of Fildena.