No no
Sherlock has had KC twice now and both times, I just let it pass through. The retching and coughing is awful and makes you feel it could be worse than it really is. I personally am NOT a fan of antibiotics UNLESS there is just cause. KC in dogs is simply, a common cold in humans and we have to let time pass in order to rid ourselves of that strain. Antibiotics are good for INFECTIONS, but not viral as everyone is saying. If your vet is recommending another round of antibiotics, I would ask why or ask for another consult in order to go with them. Prescribing them blindly shouldn't be done, as it suppresses the immune system.
I would let it pass and you can give a tablespoon of honey 2x per day for coughing. I did it instead of cough medicine and it worked just as well and it's natural.