Do you have an ER vet? K9 Advantix contains permethrin which can be very dangerous. We have a little Yorkie on another forum I belong to at the vets now fighting for his life after a dose of Vectra 3D which also contains permethrin.
This explains permethrin toxicity:
Permethrin and Pyrethrin Toxicity in Dogs
This explains permethrin toxicity:
Permethrin and Pyrethrin Toxicity in Dogs