Only copper treatments contain copper. Other medications don't. If you're truly going FOWLR with no intent on ever getting corals, or having any shrimp, crabs, or snails in your tank, then you can use copper in your main. Copper in your main tank will kill any of those things. Copper will not "kill" the live rock, but many antibiotics that you might use would kill off the bacterial populations that will live on your live rock.
The best thing to do is invest a big whoppin $50 for a quarantine tank setup (10g tank, heater, biowheel) and use it. Not only will it help you avoid putting diseased fish into your tank, it gives you a place to treat them if they get sick, without messing up your main tank.
{Edit: Just realized that using copper in your main tank, with rock and sand, is a problem because the calcium based rock and sand will absorb the copper making it nearly impossible to keep stable levels of the copper solution in your water. That why you usually use it in a bare QT with no rock or sand. }
