My cat has developed unusual tremors-- help!

My cat sleeps beside me at night, and for the last month I've noticed that as she falls asleep, just before she begins the REM deep sleep, complete with paws batting and the usual cat dreams, she has really severe muscle spasms throughout her body. Her body tightens, then releases, then tightens again only a second later. They are not consistent with her breathing. The spasms haven't woken her up yet, though they seem to be getting worse. I took her to the vet, who was able to rule out any muscular or arthritis issues, but no one could think of any reason or remedy for the spasms.

My cat is 6 years old and otherwise healthy. She did recently have Advantage flea drops, but I can't find any information that would possibly link the spasms to this.

Does anyone have any idea what might be causing these spasms? How can I help her?

Thanks in advance...

I got a package of Advantage from my Vet awhile back to use on my cats. As I always do, I read the warnings that came in the package. I don't remember what the potential side effects were that they listed, but they were alarming enough to me that I took the package back to the vet. I'm trying to find information about it on the web, but haven't come up with anything yet. I'll keep looking.

Okay - can't find anywhere where all the potential side effects are listed. Not even on the Bayer site. If you have the box the Advantage came in, there should be an insert in there.

I did find an article about "spot on" flea products (which includes Advantage). I don't know what the ingredients for Advantage are specifically, but Fipronil can cause body twitches/tremors and Permethrin can cause tremors.

If it were me, I would stop using the Advantage just in case. Hope everything turns out okay for your kitty!

When she is spasming, can you wake her? Some cats twitch more than others while they are dreaming. People do it too sometimes. If you can wake her, and she eats, drinks and excretes normally, I wouldn't worry about it. If you can't wake her, you may want to ask the vet about the possibility of a seizure or other neurological disorder.

Wow-- I haven't been able to find any reasonable amount of information about Advantage either... I had no idea that something as simple as flea drops would be such a clandestine matter!

I'm glad to know that if I can at least wake the cat it's a good thing. Her spasms are not like the usual cat horse-play while they dream but more like constant chills that tighten her body, release, and tighten again, so it really seems out of the ordinary.

If these spasms are related to the flea drops or another run-in with something toxic (maybe she taste-tested something she shouldn't have?) do you think they will go away eventually? I'm hoping this is a short-term thing for her-- I've only used the Advantage twice and will for sure not try it again just in case!

Thanks-