They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. Viagra vs. You can also buy Viagra, generic unbranded Sildenafil , and other licensed ED treatments online, from approved sites, without needing to visit your GP. These are commonly prescribed for an enlarged prostate or male pattern baldness. However, Viagra Connect is only available over the counter in the licensed strength of 50mg.14th July Manual Health Centre See your GP for a prescription. A prescription from your GP may allow you to get Viagra (or unbranded Sildenafil) for a lower cost than over . The 7 Best Over the Counter ED Medications August 23, Medically reviewed by David Culpepper, MD Erectile dysfunction is a frustrating, sensitive experience for any guy. . 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.