Fildena 150 is useful in treating erectile dysfunction in men. The main ingredient in this medicine is sildenafil citrate. This medicine increases the speed of blood in the penis. This medicine allows an erection to last for hours during intercourse. The effect of this medicine can last for 4 to 6 hours. This medicine should be taken with a glass of water. This medicine is usually taken before a meal but this medicine can also be taken after a meal.