Some care tips are considered by the people before the use of Viagra. If you are willing to use it then you should also consider them. In these care tips you should have knowledge that use of nitrates with Viagra is harmful for your health. It means that you should avoid those medicines which contain nitrates. Viagra cannot protect you from transmitting the sexual disease . AIDS. You have to consult with your doctor if you want to save yourself from such health problems. Viagra can be found easily from the market. You can buy Viagra in three doses . 25 mg, 50 mg and 100 mg. Most of the doctors suggest a heavy dose to a person having age range from 20 to 35 years. A light dose of Viagra is best for that person have an age more than 60 years.