Their were special protocols/conditions that had to be met to be prescribed i.e. had to be started by a specialist dr not just the local dr and that kind of thing. Had to also have approved reasons.
When i first started on the opioids the first prescription was by the specialist in hospital. The second was by the registrar (senior doctor who worked at the direction of the specialist) and then by my GP (local dr) they referred my care back to.