[blam]

" Doxy is a good drug to have for preppers."

I agree 100% and already have a sizeable stash of it. (I keep it cool, dark and dry and expect it to still be good after fifteen years)

[Jubal Harshaw]

With time, probably much less than the 15 years you are planning, tetracyclines like doxycyline degrade into toxic products. In rare cases, expired tetracylines can cause Fanconi syndrome, renal failure and, potentially, death.

Doxycyline is safer than other tetracycline in this regard, but the potential for renal damage from expired Doxycycline is something to consider when intentionally using 15 year old antibiotics.

Just buy some new stuff every now and then, already, so you don’t have to rely on 15 year old antibiotics when the time comes!