The difference between the vardenafil molecule and sildenafil citrate is a nitrogen atom’s position and the change of sildenafil’s piperazine ring methyl group to an ethyl group. It works for up to 36 hours. 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. Talk to your doctor about eating grapefruit or drinking grapefruit juice while taking this medicine. The medicine can help achieve an erection when sexual stimulation occurs. This is not a complete list of side effects and others may occur.Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. This boosts blood flow and helps you get an erection from sexual activity. How oral medicines differ Each oral medicine for ED has a slightly different chemical makeup. Vardenafil is used in adult men to treat erectile dysfunction (impotence). Vardenafil may also be used for purposes not listed in this medication guide. uses What is Levitra (Vardenafil) used. Vardenafil is a medication that treats erectile dysfunction. ED is the inability to achieve and sustain an erection suitable for sexual intercourse. This medication works by increasing blood flow to your penis, which helps you maintain an erection.