It depends on the drug (and maybe the state). I have to show ID for a couple of prescriptions I have, and my understanding is that it then goes into some kind

It depends on the drug (and maybe the state). I have to show ID for a couple of prescriptions I have, and my understanding is that it then goes into some kind of database that gets cross-referenced between pharmacies to make sure that I don't have multiple prescriptions at multiple pharmacies. I think that came about as part of the opioid crisis, because some people would have 5 different doctors write prescriptions for the same meds to 5 different pharmacies. No one had a way to detect that someone was getting 5 oxycontin prescriptions.