Sorry, I don't know that med and have no clue at all if eating the tablets can do any harm, so let's hope not.
I take it the tablets are meant to treat the water and not the Oscar internally, no? Seeing now how two Oscars ate them already, I'd suggest to take a bit of tank water first and dissolve the tablets first in that if possible, then pour the solution in close to the filter outlet. Guess you got that idea yourselves meanwhile but thought better to be safe.
Good luck, hope the meds help now either way