People taking nitrates like nitroglycerin Nitrostat or isosorbide mononitrate Imdur should not take PDE5 inhibitors, as doing so could result in a dangerous drop in blood pressure. We also looked at additional services, such as access to digital pharmacies and home delivery options. Independent online pharmacies operate solely on the Internet, either domestically or internationally. Some people may also have ringing in their ears tinnitus or dizziness. Most erectile dysfunction medications belong to the drug class known as PDE5 inhibitors , which help relax the muscles and increase blood flow to allow for a full erection. Your primary care doctor should always know what medications you’re taking, including ED pills prescribed by another provider. If you experience chest pain, dizziness, or nausea during sex, seek immediate medical help.CHOOSE BRAND-NAME VIAGRA. The original little blue pill prescribed by doctors for over 20 years. Clinically proven to treat men with erectile dysfunction (ED) Ongoing . Cart. Transfer your prescription for Sildenafil (Generic for Viagra, Oral Tablet) on Amazon Pharmacy. FREE SHIPPING for Prime members. According to price-comparison site , generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s .