- The effects of naloxone only stay in the system for about an hour, which is a shorter amount of time than some opioids. This means that it is possible to slip back into an overdose after the naloxone wears off. It is important to always call 911 in the case of an overdose, even if naloxone is administered
*Missouri has recently enacted a 911 Good Samaritan Law that offers protection to those who call 911 during an overdose. Click here for more information.