As with sildenafil, a high-fat meal or alcohol keep the body from absorbing it as quickly. Pharmaceutical companies can also put a significant amount of investment into the marketing of a brand-name medication. 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. How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. Lastly, although sildenafil is considered interchangeable with brand Viagra, they do have slightly different inactive ingredients.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* with . This means that generic sildenafil is just as effective in treating ED as Viagra is when it’s taken at the same doses as Viagra. It also means that sildenafil and Viagra can cause . More about Viagra Generic Status: Lower-cost generic is available. Lower-cost generic is available. Ratings & Reviews: Sildenafil has an average rating of out of 10 from a .