flea collar reaction?

Question
I realize this may not be your expertise, but you were the only one available. I recently purchased a Hartz advanced care 2 in 1 flea and tick collar for my 5 year old Havana Brown cat. He wore it for about 2 days. Shortly after putting it on, he seem to scratch more around the collar. I'm sure he also licked or bit the collar a little. After 2 days I took it off and after the next day or so, I noticed he stopped eating and seemed depressed. I took him to the vet yesterday and everything seemed to check out ok (blood work was ok). He gave him fluids and I think some antibiotics. He also said he checked for somethng from the flea collar(I'm not sure what he tested for, but he said it was ok).  I'm not sure, because I brought him home this afternoon and he drank some water and ate a little food but hasn't eaten or drank now for 12 hours and still seems depressed. I've read online that depression can be caused by some Hartz products. If so, what can I do to help my cat?

Answer
Many cats get toxic from insecticides. This is what you are describing. Ask your vet to check with Hartz about a specific antidote treatment for the insecticide in the collar.    It may take a while for the insecticide to release from the fat under the skin.