I have people that I can call to get a script if I need one.
I also have a few months of medicine in stock as well as some antibiotics etc.
However, in addition to supplies on hand, I always try to figure out a way to provide necessities independent of suppliers. Self sufficient as much as possible.
As I point out in by book (and have experienced in real life), having alternate antibiotics on hand is not necessarily of value unless you also have someone around who is qualified to diagnose.