i can add a little bit that i know about 2 opiates, you can add more if you know.
oxy/hydrocodone converts into two metabolites, noroxy/hydrocodone and oxy/hydromorphone, norooxy/hydrocodone is useless for analgesia and for recreational value, you can slow down the metabolization by drinking grapefruit juice. oxy/hydromorphone is a minor metabolite and is much more potent then the precursors but is minimal in effect, the high received from oxy/hydrocodone is produced by oxy/hydrocodone it self and possibly helped by oxy/hydromorphone.