Be sure the one you choose works in your state. The best online pharmacies are accredited by the National Association of Boards of Pharmacy and are licensed in every state in which they trade. In some cases, online ED providers accept health insurance. Read our editorial process. All PDE5 inhibitors, including Viagra and Cialis, require a valid prescription regardless of the pharmacy or provider.According to price-comparison site test1.ru, generic Revatio will cost you as little as $ per pill, depending on where you fill your prescription. That’s compared with . Vision changes. Muscle pain. But there are some differences. With Viagra, there is a higher risk of vision changes than with Cialis. Among people who take Viagra or sildenafil, 3% . $12 View other PDE5 Inhibitors Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial .