I posted this on the dotcorny list, thought i had here too. My previous setter had flea issues all the time, and i used advantage religiously, and when i got Cassie, i did the same. Then when i started tracking, i kept hearing about deer ticks, so i started using Advantix. First dose fine, the second month, after 4-5 days, i woke up to Cassie flipping out, i was groggy, didn't realize at first she was having seizures, panicked that she had eaten something poisonous and was dying. Once she calmed down, I called a friend who calmed me down, then i called my mom (who reminded me of something - see below) and before the vet office opened i started doing some research online, apparently Advantix has caused seizures in dogs before - the vet office kind of pooh-poohed it at first, b/c they said it would have shown up sooner - like 2-3 days. Later they said she might be sensitive to it. I have stopped using all chemical flea meds.
Here is what my mom reminded me of - I went through this with my first Irish when i was a kid. He also had a 'flea allergy' (I liken that to me saying I have a mosquito allergy - they bite me, I react
) but my parents got some Proban, and we applied the liquid between his shoulder blades every month. He was about 5 at the time, and he started having seizures - not sure how long between starting the meds and the seizures beginning, but we didn't make the connection until maybe 4 years later, when we got a puppy, who also developed flea allergies, and we also used Proban on him, and HE developed seizures. Now my parents could believe one dog, esp in a breed that was kind of inbred by that point (the height of their popularity - although he was otherwise completely healthy) but not in the new dog, so after some investigating they stopped the Proban and the seizures disappeared.
Cassie has not had another seizure. I rest my point.
We also had a bunny that was infested with fleas. She was the only one that ever had them, we used Advantage on her all the time and it never made a difference. (We bathed her, we bombed her cage - outside of course - we bombed my son's room, we tried every flea spray under the sun, we used diatomaceous earth, nothing ever worked.) She has since passed away, and so have most of our household flea problems. I don't think Advantage works as well as it is touted to, and when i think of all the money on spent on that crap over the years, i am sick. (Because we not only had to treat one bunny, and the dog, we had to treat the other 3 bunnies, and the cat - 6 pets x 12 months x $15 (roughly) = $1080 a year)