It is true that it can effect some pets so adversely that it can kill them. However, there are millions of pets that use these medications every month with no adverse reactions. Vets give this medication out to all their clients and rarely do clients question them. I believe that all pet owners need to question the medication they are giving their pets and make their own decisions on whether or not they want to give their pets the medication.
My cat does the same thing your gabby did when he gets his revolution every month. With him i think its more that he doesn't like the wet stuff i put on his back. this happens with a lot of pets. however with some that do this behavior it could be that they are itching or there is a slight burning sensation because they are allergic to it or it causes irritation to the skin or scent glands.
I personally do not use flea medication or heartworm medication on my yorkie anymore. I did for the first summer but then decided i didn't want to use it on her anymore. In my location i haven't had a problem with finding fleas or ticks on morgan, nor is she outside enough to have a problem with these bugs or mosquitoes.
I wash her once a week with Minksheen which has Cedar and Citronella oils in it to repel bugs.
MinkSheen Pet Shampoo