The prior authorization is simply an effort on the part of your insurance company to make it difficult to secure the medication using your pharmacy benefits. You have already met with your doctor, discussed the medication, its risks and benefits and your doctor has prescribed the medication.
The prescription is available at your pharmacy and you can immediately pick up the medication. Without the prior authorization your insurance company may ask you to pay directly for the medication, but ultimately that is your choice.
You can think of a prior authorization like a rebate. If you’ve ever bought anything that offered a rebate you’ll appreciate that it is very difficult to secure that rebate and that is intentional. The prior authorization process was created by insurance companies to save them money and make it difficult for you to get your medication while using your pharmacy benefits.