As an emergency room physician in rural East Tennessee and SW Virginia, I’ve seen a number of “casualties” from human use of animal antibiotics. First, the binders used in vet meds are not tested, usually, for lack of general reactivity in humans; if your genetic haplotypes are extremely different from cows and pigs, you might have an allergic reaction to the binder, not the antibiotic; I’ve seen this happen three times, once to bovine antibiotics, and twice to pig meds. Solution: test a small amount of the agent (e.g. 1/8th of a tab) and if no reaction in 24 hours, maybe you’ll be okay (this is not advice and I don’t recommend vet meds for humans or even half humans).
Second: the expirations on vet meds are not as closely monitored as with humans. Usually, an agent can be okay for six months past the stated expiration (and, you sometimes can’t trust the stated expiry on vet meds); after that, no effect. Worse problem, with tetracyclic antibiotics (tetracyclines themselves, doxycycline and similar), the expiration is critical. Two weeks after the expiration date, these agents can and frequently do become nephrotoxic. I’ve seen two patients, now on dialysis, from kidney damage from old tetracycline. So, beware. Best bet is get to know an MD who will prescribe 1-2 courses of commonly used or broad spectrum antibiotics for each member of your family, ask the pharmacy about expiration dates on the source bottles (he may refuse to tell you, if so, forget it), and then rotate every year. good luck and beware. Things are never as easy as they seem. – Wardoctor (a Desert Storm vet)