You can take this medicine with or without food 30 minutes before sex, depending on the dose. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. Medicines that you take by mouth are called oral medicines. By stopping this enzyme, the drug allows better blood flow into the penis, meaning better erections. With Viagra, you get the iconic blue diamond-shaped pill and the brand-name box.Viagra is only available with a prescription in the United States, Canada, and most other countries. Viagra is sold under the generic name sildenafil, which is also only available . Learn More IF YOU CHOOSE BRAND-NAME VIAGRA, MAKE SURE YOU GET THE BRAND NAME Your prescription may have been filled with a generic version instead of . You may find well-known ED drugs for sale, as well as many “natural” remedies that promise to give you the same results. When samples of milligram Viagra tablets .