Naloxone has one indication, and one indication only: respiratory depression which is suspected to have been caused by opioids.
Narcan should not be used as part of a "coma cocktail", or just because someone is unresponsive and we don't know why. ...
Now that said, given the severity of the opioid crisis that we are experiencing, I don't think there is anything wrong with having a high index of suspicion for opioid overdose in a comatose or very lethargic patient, and a fairly low threshold for using naloxone for that reason.
But you still need to have respiratory depression, and I think you still need to have some reason to think that the cause of the respiratory depression is opioids, in order to justify its use.
I had a rather interesting case tonight. Man in his 60s is witnessed by family to go unresponsive. CPR by FFs, found to have a pulse by medics (no epi or shocks). Man is older, no possible cause of unconsciousness reported by family. Glc ok. Other than some apparent agonal resps, vitals are stable. Medic nasally intubates successfully and transport. Pt. begin waking in resusc bay, following commands, etc. Vent parameter are great and I extubate before EMS is out the door. Man admits to snorting heroin. Now, I don't typically give narcan to every unresponsive person, but in certain cases it is worth a try. One of those potential cases would be if you are about to intubate. Using a small dose or 2 (0.2-0.4mg per dose) might be worthwhile. However, I would only advocate that in cases where there isn't other findings suggesting another cause (e.g. signs of trauma, a blown pupil, posturing, etc.). Anyhow, that was live and learn case for the medic and no harm was done. (Family later 'remembered' that he had a heroin problem.)