Metro Med medicated food is a very good food. It takes care of certain bacteria infections as well as intestinal worms and a few other internal parasites. It is purported to be one of the best remedies for combating dropsy.
Medigold is yet another antibiotic - it is effective against different strains of bacteria.
Between the two of them you will cover a large band of infectious bacteria and a few parasites.
The main problem you are going to have it that these are basically food infused with antibiotics. They have a limited shelf life. I have found that vacumn packing the food into individual "dose" packages lengthens the shelf life by as much as 3 months, but it still is a relatively short time. You cannot freeze it or refrigerate it to lengthen this time.
So, purchasing the medication in hopes of stashing it away for future use is probably not the best idea. Unless you have immediate need, chances are that it will no longer be good when you do need it.