I always have left-over valium, flexeril, & hydrocodine from past ski accidents that go into my backpacking first aid kit. Of course, I follow prescription directives not to mix drugs. I have even asked my doctor after a wrenching my back from a ski fall to give me some extra for summer backpacking. However, I'm a 56 year old outdoor warrior.
I rarely have had to use it, but a few times it's saved me. All of the above have stayed potent for years.
Better living through chemistry!

