You should also call your insurance company to see if they cover erectile dysfunction medications. Online ED consultations offer privacy, convenience, and affordability while allowing you to quickly get the medications you need—the same day, with some services. While each PDE5 inhibitor differs slightly, they’re very similar in treating erectile dysfunction. According to the FDA, generic medications contain the same active ingredients as brand names, meaning there’s no difference in effectiveness or safety. Your health information should remain between your provider and yourself. Vardenafil usually works for 4 to 5 hours.”Generic Revatio is considerably less expensive, and it is the same drug as Viagra with the same safety and effectiveness,” says Bradley Anawalt, M.D., an endocrinologist and . VIAGRA does not protect against sexually transmitted diseases, including HIV. The most common side effects of VIAGRA: headache; flushing; upset stomach; abnormal vision, . Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or alcohol. Its effects .