Medicines that you take by mouth are called oral medicines. Other warning signs of an unsafe online pharmacy include outdated medication, no customer service, or suspiciously low prices. Most online pharmacies do not prescribe or refill controlled substances, like Adderall, Xanax, or oxycodone. It might work longer if you have mild to moderate erectile dysfunction. All PDE5 inhibitors, including Viagra and Cialis, require a valid prescription regardless of the pharmacy or provider. It depends on the platform and insurance provider.There is generic Viagra now. They have 20mg and mg tablets. It’s usually $/bottle depending on your pharmacy. Compare prices and print coupons for Sildenafil (Generic Revatio and Viagra) and other drugs at CVS, Walgreens, and other pharmacies. Prices start at $ Welcome!Missing: reddit. Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. This boosts blood flow and helps you get an erection from sexual activity. How oral medicines differ.