Follow-up support: Make sure you can get the help you need if questions or concerns arise after ordering. More serious side effects may include a drop in blood pressure or an erection that lasts longer than four hours. How much do ED medications cost? Oral ED medicines might not work or might be dangerous if you also take any of the following: Nitrate medicines. Video visits are available in all 50 states and D. Local drug stores have sites; you may be able to use one to fill or renew a prescription. This medicine also works best when you take it an hour before sex on an empty stomach.Yes, it can be legal as long as certain rules are followed. Whether or not it is legal to purchase your prescription drugs online depends on various factors: your location, the . 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. If you’re interested in buying Viagra online, five of the best options available are Hims, Roman, Lemonaid, Optum Store, and REX MD. Read on for full details on the process .