I need to know. If you used heroin 2 days ago and have a perscription for codein, vicodine and hydromorphone, can you get away with telling the lab that I have taken these medication instead of heroin?
well, essentially heroin and codeine metabolize into the samething.. Morphine. If they are looking for specific metabolites than they could see the difference.
But I think you shouldn't have anything to worry about