Narcan can be used more than 20 years post-expiration. It has likewise been tested to confirm viability after repeated heating and freezing and it has been found to have high efficacy in those conditions.
You CAN keep Nacan in the glove box and use it whenever it is needed. If you have it on hand, it is safe and effective to use it.
@sentimentaldom can you provide some references?
@2ck look at the comments on this post. Someone shared a link.
@sentimentaldom
posting a link to that post for convenience of others who don't see the replies
https://glitch.cat.family/@Satsuma/110114457597100028