Viagra (sildenafil citrate) can be used by male patients that are unable to have sex because of flaccid erections or erections that go away too soon. This drug is widely used for most severe cases of impotence working for the amazing 80% of all patients no matter what their erectile dysfunction has been caused by. Viagra is made by the company called Pfizer that came up with the idea, but there are also generic drug manufacturers that make high quality Viagra and sell it online. If you find the right online pharmacy, you will be able to get Viagra really cheap, at the same time enjoying very high quality of this medicine.