I wish it has gone into more detail.
I concur fully. The devil is in the details, as they say. One can purchase doxycycline without prescription for pets, and keep it for times when meds may not be available. It treats some bacterial infections including anthrax specifically (as well as Lyme disease, malaria, and certain STDs). And the production standards for veterinary medicines are high enough that they normally can be used by humans as well. HOWEVER – that 10% mentioned by the Harvard article is where things can break down quickly. The tetracycline family (of which doxycycline is one) can cause liver damage if it’s expired. Liver damage can also occur with in-date doxycycline, but apparently that accelerates dramatically with improperly stored and/or longer term expired batches.
A good article somewhat from our perspective is:
Note the “Part 1″ of the article linked at the top of this article. It discusses antibiotics for fish. Yes, you can find antibiotics in pet stores for fish, but those for fish are NOT FDA certified or regulated. Those for warm-blooded animals are (though still with some differences in standards).