Could you please tell me what the rules are, for a doctor prescribing opiates such as (fentanyl)?

Are doctors allowed to re-prescribe opiates over the phone without an office visit? Are they allowed to fax them to the pharmacy?

If they can, how often MUST a doctor that is prescribing them, see that patient?

I have looked everywhere for an answer to this question. I have even asked a couple of doctors, but they are not sure. (scary huh)?

I would appreciate the correct law on this, if anyone knows it.

Thank you in advance!