Advantage problem

[sharpstick]

I've been using Advantage for our nine(!) cats for several years.
One of our cats is having problems with it. He is a neutered male, 16 lbs and 12 years old, in pretty good health. He is kept indoors, but some of our cats go outside, and all of them are allowed on a screen porch. We live in Tampa FL.
He has always hated his Advantage applications and runs away in distress when he sees the applicator, so we assume that it is causing him discomfort. About a year ago, it started causing hair loss and one time the skin was lost and an open sore developed. I can't tell if the chemical caused it or he was scratching the area, so next time made sure it was applied high enough on his neck and monitored it.
I brought this up to a very knowledgeable person at our local pet store. She said to stop giving it to him because it could cause convulsions or death.
I can't find any confirmation of that online, but we had already decided to try some alternatives before that conversation.
She suggested switching to Comfortis(apparently by prescription only) or Revolution. (She didn't mention Frontline).
I want to try a non prescription path first. I'm unemployed and am trying to keep costs down.

[Dave_ph]

My kitty doesn't like the application but it didn't have the impact that my one early application of Hartz did.

Could just be a alergy. Advantage doesn't have a history of problems. Assuming you're using the Advantage for cats and not the Advantage for dogs. I think the dog formula has permethrin in it.

I'm in Palm Harbor. It's fleas season.