This site is intended only for U. They’re often the first line of treatment for trouble getting or keeping an erection, called erectile dysfunction ED. Since , the ED medication Viagra has been available over the counter at many pharmacies, under the brand name Viagra Connect — only in the licensed strength of 50mg. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. It lasts 4 to 5 hours, or longer if you have mild to moderate ED. These medicines are called PDE5 inhibitors. Vardenafil usually works for 4 to 5 hours.Currently, there are no over the counter alternatives to Viagra available. Viagra (sildenafil) is a prescription medication, meaning it’s not available over the counter from your. Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles . Is there an over-the-counter Viagra? Viagra is only available with a prescription in the United States, Canada, and most other countries. Viagra is sold under the generic name.