Recent heart or blood vessel problems. The four main medicines taken by mouth for erectile dysfunction are: Avanafil Stendra. Pearlman says. ED can sometimes signal an underlying medical problem, like heart disease or diabetes , that needs to be treated separately. When choosing one, tell your doctor or other health care professional what your preferences are, such as cost, ease of use, how long the drug’s effects last and side effects.Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles . 11 Viagra Alternatives Approved by Doctors. Alternative medications. Side effects. Natural remedies. Other options. Treatment. When to see a doctor. FAQs. Takeaway. 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 .