
Kennel cough itself is a virus and therefore antibiotics has no effect whatsoever. Only if a secondary infection develops are they of use. I don't believe in using antibiotics willynilly as every use is a tiny step forward for the bacteria to develop resistance. The slower that process is the better chance of our scientists keeping ahead with developing new antibiotics to counter this. I therefore believe they should only be used if an infection has been confirmed by culture or strongly suspected from clinical examination.
Your vet should be able to determine if a secondary infection has occured but please keep your dog in the car until you have spoken to him, he may come out to the car to examine him or he may have another entrance to the surgery avoiding the waiting area. As I said, my understanding is they are treated as infectious for 7 days after coughing has stopped.
I give mine paediactric Benylin, adjusting the dose to match a similar sized child, this does not
cure anything but does seem to relieve their symptoms and perhaps if they are not coughing as much the throat will not become so raw that bacteria can get in and cause an infection but I am just speculating there.