The first responder arriving on the scene would have to establish the patient's level of consciousness, and determine that there is an overdose. Usually there are good signs because there are needles close by in an alley to determine that. Then a little pain stimuli to see if you can arouse the person. You would next assess and assist the breathing and then we have a small vial that we load the needle with and it's an intramuscular injection. I'm not sure of the dose. Sometimes you'd have to do multiple injections, but when the naloxone does take effect, you have a patient coming out of their high in 20 seconds and often quite upset you've taken their high away.
On October 18th, 2016. See this statement in context.