This is a randomized, prospective trial that will compare clinical outcomes for parenteral naloxone according to the standard of care (TAU; administration via intravenous [IV], intramuscular [IM] or intraosseus [IO] delivery) versus intranasal [IN] for the prehospital emergency treatment of suspected opioid overdose. Ambulance squads in Adams, Clermont, and Scioto counties in southern Ohio will be randomized to administer either standard care or IN naloxone as the initial response to a suspected opioid overdose.