An erection results from an increase in blood flow to the penis. Note that Viagra is only available in three doses: 25 mg, 50 mg, and mg. A phone or video consultation is sometimes required for legal purposes. 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. Most online pharmacies do not prescribe or refill controlled substances, like Adderall, Xanax, or oxycodone. It’s best to check your chosen provider’s site for more information. Psychological factors like stress, depression, or anxiety can also contribute.While you’ve likely used a brick-and-mortar pharmacy to get your prescriptions, online pharmacies can be a convenient and efficient way to get the medications you need. . To get a prescription for Viagra, start by making an appointment with your doctor to discuss your erectile dysfunction, as well as your medical history. Then, if you and your doctor . Viagra is an effective option for ED. Generally, you should take Viagra about 1 hour before engaging in sexual activity. Viagra can start working in as little as 30 minutes, but it can .