You would be surprised, or not. It typically takes a really long time for your prescribed meds to be approved so you can take them while in jail. Not sure about the prison process but I know plenty who it either took like a month or didn't happen at all. Medical wings in jails are stretched so thin because of opoid addiction that they keep detoxing patients in separate units until they're either bailed out or "done" detoxing and moved. And no, you don't get any help for that either.