My five kitties almost died

I used Sargeants Flea & Tick drops for dogs on my five kittys. I ran out of Advantage and thought this would be ok until I got to the vet. I split 2 doses between my five cats, what a HUGE MISTAKE. I applied small amounts to all of them around 7:00 PM, by 9:30 PM i noticed the smallest one had tremors, twitching, trouble walking and stayed in a crouched position not even laying, just crouched. I though she must have licked some of the medicine off her back some how so I tried to induce vomiting with proxide as suggested. That did not work but, I also bathed her again with dish soap to get the oil off her. I kept her in bed with me as she had labored shallow breathing. By midnight one of my other cats came in the room to lay but started having a full blown seizure and foaming at the mouth. At this point I realized there had to be something more serious than I thought. I rushed two of them to the Pet ER and they admitted both of them and proceeded to tell me that this is VERY COMMON with the product. I was told to go home and wash my other three cats with DAWN dish soap to get this off their skin and watch for signs of tremors, twitching, foaming of the mouth etc. I was able to wash two of them but the third cat was already out side for the night and could not locate him. Once I picked up the first two cats from the ER and brought them to my local pet hospital for continued support my other cat came home and was shaking, had tremors and some what lethargic. I rushed him to my local pet hospital with the other two for treatment. Two of them were released after being treated with IV fluids and sedation and the third one that had the seizure is still in critcal condition with inflamation of the brain. How can this product still be on the market with all the complications noted on the intranet. I wish I would have done some research on this before putting this on all five of my cats……