Two years ago I had treated my cats with Hartz flea treatment for cats. Within an hour all 4 were having uncontrollable twitching. It was horrible. I had to place each one in a separate box to protect them from injury. I could afford a vet visit for all for so, I internet searched for answers. Come to find out many, many people have experienced this before. I had to eyedropper water to flush their system and hand squeeze their bladder to urinate. All normal functions weren’t working. It took 30 hours for the effect of Hartz to ware down for them to acknowledge me and their surroundings. If this is a known thing, how is it allowed to be sold?