All this discussion has left out one important item: painkillers
I was at Waktobi and one of the guests had a pretty nasty lower back injury.
On of the doctors on our boat started asking around to see who had what. Fortunately I had some Darvocet or something like that.
It is exceedingly difficult to get a doc to prescribe stuff like that on a preventative basis but I always get these filled completely even though I know I'll never use 'em.
Almost everyone has some stuff like this sitting around the house. Controversial I know but...
My kit is typically:
Malarone
Cipro
Zithromyacin
Some generic painkiller like Tylenol 3
Robaxin (a muscle relaxant)