I’m a radiologist. But I’m starting to feel like I’m being fooled by a bot with fairly few lines of code. 

But on the off chance that you were actually curious about how prescribing medicines or using medical tests works in the United States, here goes: no government entity can tell a physician how a medicine must be used. Nor how a test must be used. But there are regulations on charging for services such as medicines and tests. Any physician can prescribe any drug in the best interests of the patient, bound only by malpractice, which is a standard set by local medical practices. But government can deny you payment.