EMS should do just what their name suggests, administer emergency meds to keep the person alive so they can be treated at the hospital. Narcotics, generally speaking, are not a part of that. Sometimes narcotics can mask symptoms so that the patient is harder to diagnose and treat at the hospital. The fewer substances introduced into the patient by EMS, the better. There is also the problem of the narcotics being taken/stolen from them. It puts the EMTs needlessly at risk.