How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. When choosing one, tell your doctor or other health care professional what your preferences are, such as cost, ease of use, how long the drug’s effects last and side effects. Read and follow these instructions carefully before you start using sildenafil and each time you get a refill of your medicine. To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and site usage information with other information we have about you. The body takes longer to absorb it after a high-fat meal or alcohol.Drug Images Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take by swallowing. It’s usually taken . Generic Viagra (sildenafil) is an alternative to the branded Viagra drug that can be used for treating erectile dysfunction (ED). It’s now sold by many manufacturers, including online. Drug Images What is Viagra? If you have erectile dysfunction (ED), your doctor may recommend that you take Viagra. It’s a prescription drug that’s used in adult males* .