My 5 year old pure bred maincoon died tonight from harts flea meds. The medication was for for cats 12 weeks and older over 5 pounds. 3 days ago I gave him Hartz topical med for fleas and he started going downhill with in the hour. He was basically poisoned by the stuff and there was nothing we could do. I learned of pets dying across the country from a friend at work after mentioning to her what had happened. The vet asked if we accidentally gave him large dog meds. I got out the packaging and left over treatments to show what I had used. Really too upset to write more details, only writing this as a warning to other pet owners.