Common ones include: Flushing of the skin. Otherwise, Viagra and Viagra Connect are both taken in the same way: one tablet about an hour before sex — and only one tablet per day. However, Viagra Connect is only available over the counter in the licensed strength of 50mg. Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. Viagra, known as the blue pill, can be prescribed by doctors or clinicians in strengths of 25mg, 50mg, and mg. Its effects might last longer if you have mild to moderate ED. A prescription from your GP may allow you to get Viagra or unbranded Sildenafil for a lower cost than over-the-counter Viagra Connect.You can also buy Viagra, generic unbranded Sildenafil, and other licensed ED treatments online, from approved sites, without needing to visit your GP. Even though erectile . AdNo credit card required, no fees, & no commitment. We will find the lowest price near you! GoodRx® finds the lowest prices at every pharmacy near you. See how much you can save!GoodRx helps people pay for Rx they otherwise couldn’t afford. – Patch. Can I buy generic Viagra over the counter or do I need a prescription? In the U.S. and most other countries, generic Viagra is only available with a prescription.