my 10 yo lab mix has been nauseated and had four episodes of vomiting after Vectra. It is the only thing different in his life.
My other dog had no reaction that I have noticed. Both eat the same diet and have not been around any new animals, people or products. Vectra is the only difference. This was only his second application.
The vet of course says it could not be the vectra. He has lost a few pounds.
I hope there has not been any permanent damage based on the comments above. I think I will switch back to Frontline Plus which we used for years with no fleas.
I didn't like: Side effects.