I was completely unprepared as the medical emergency was a new one and had only occured a few days before travel (in which I was returing home). I've never had medicine that required refrigeration before (not since I was a child).
I didn't pre-prepare with an insulated bag as I never even imagined that my slim little paper bag would present a problem for an airline that is famous for providing superlative service.

But it is really, really unpleasant to have to rely on the generosity and common sense of an individual FA. Official airline policies like the one I was confonted with stink and I'd rather avoid airlines which implement them.