Its effects often last for 4 to 5 hours. If you have an erection that lasts more than 4 hours, get medical help right away. These medicines are called PDE5 inhibitors. These small differences affect the way each medication works, such as how quickly it takes effect and wears off, and the possible side effects. Stop taking VIAGRA and call your healthcare provider right away if you have any sudden vision loss sudden hearing decrease or hearing loss.Keep in mind that Viagra isn’t approved in the United States to treat PE. And it’s not recommended in current PE treatment guidelines from the American Urological . It was approved for medical use in the United States and in the European Union in [5] [8] [11] [12] In , it was the rd most commonly prescribed medication in the . Viagra (sildenafil) and cost. Viagra (sildenafil) is a brand-name oral tablet prescribed for erectile dysfunction. The cost of the drug with and without insurance can depend on .