Yes, naloxone is very safe. It has been used in hospital emergency departments and by paramedics for decades to reverse opioid overdoses.
Naloxone has no effect if you have not taken opioids. It will not get you high and does not cause addiction or dependence. If you have taken opioids, naloxone may cause you to experience withdrawal symptoms. While uncomfortable, these withdrawal symptoms are not life-threatening.
In rare cases, some people may have an allergy to naloxone.