[yorkiemom]

Hope you don’t mind if I go off-topic.

I’m looking for some vet meds to have on hand, but don’t want to have to invest a ton of money since it appears they last 12-18 months only.

Out of this list, which 2 would you say would be best to have?
Penicillin 500mg Fish Pen Forte
Amoxicillin 500mg Fish Mox Forte
Ciprofloxacin 500mg Fish Flox Forte
Cephalexin, or Keflex 500mg Fish Flex Forte
Ampicillin 250 mg Fish-Cillin
Metronidazole 250 mg Fish-Zole

[Kartographer]

They last far longer than that.

Many Medicines Are Potent
Years Past Expiration Dates

http://www.terrierman.com/antibiotics-WSJ.htm

[Sarajevo]

If it's a "cillin" it's penicillin related.
Amoxicillin wold be the best for upper respiratory infections and it has broad spectrum activity.
Ciprofloxacin is great for urinary tract infections, lower respiratory infections, and infectious diarrhea.
Cephalexin is good for skin and skin structure infections, and is a good alternative to penicillins for those with a penicillin sensitivity.
Metronadizole is useful for anerobic infections such as peritonitis, diverticulitis, empyema, pneumonia, aspiration pneumonia, lung abscess, diabetic foot ulcer, meningitis and brain abscesses, bone and joint infections, septicemia, endometritis, endocarditis, and giardiasis.

I don't know what you are looking for, but there is a whole myriad of antibiotics, some which work better than others for certain infections. They will generally last over 5 years if kept in a cool, dark place. The dates just ensure rotation of stocks.