IMO/E...the number one medication is Fresh dechlorinated water from water changes and second best is the tannins-then the Epsom and aquarium salt.
I have found that getting the stress controlled first often is all that is needed for the immune response to kick in.
Biggest stress for fish-is water quality issues-this can be both too dirty or too clean-then extreme changes in temp and chemistry. Then you have water movement and space that can be a big stress factor with this species.
I personally don't recommend or use the OTC antibiotic/medications, however, I am not critical of those that do-But I have found that when they are not used properly that they can often cause more problems than help. They can also be ineffective with some extreme water chemistry related to pH, KH/GH. Over use can cause toxic issues and resistance-plus they not only kill the bad bacteria they can kill good bacteria that is keeping the bad bacteria controlled in the first place.
These products also have a shelf life and can expire as well as be useless if stored improper and light/photo sensitive.
Above all, prevention is the best method-but even with the best care/husbandry- our fish can still get sick or we buy them that way....