For all of the web searchers, apparently Advantage can make cats have seizures.

Six months ago Lucy the cat got fleas, most likely from the vet where she’d been for some minor surgery. We applied canine advantage to our dog and feline advantage to the cat. Within minutes after applying the frontline to the cat, she had a small seizure. I’d had her 12 years at the time and, to the best of my knowledge, she’d never had a seizure before. We decided never to reapply Advantage to her.

This week, our dog got fleas. We applied canine advantage to the dog and nothing to the cat. She had a seizure a day later, her first seizure, to the best of our knowledge, since the last time we used advantage. Our vet thinks it may be because she likes to sleep in his upstairs kennel on his bed during the day because it gets a lot of sun.

These are the only two times I know of her having a seizure since I adopted her in October 1999. So if you find this via google, you’re not the only ones and I’d stay away from advantage, or at least closely monitor your cat if you use it. Our vet recommended Frontline for the next time either gets fleas; if we have to use it, I’ll post again.

Other accounts of cats having seizures after exposure to advantage are available here