An OD is a self inflicted wound.  The presence of Naxolone simply saves them and gives an opportunity to do it again.

"The lives of 24 people were saved by receiving naloxone, an overdose reversing drug, which is available without a prescription at local pharmacies.

In 16 of the cases, people were given naloxone by a friend, family member or bystander. Another 11 people received it from police or emergency medical services."

So Why are Epi-Pens not similarly available?  Instead they are priced stratospherically and not handed out willy-nilly like naxolone.