concerns about flea meds ingestion

We're having a flea problem here. They seem to be staying on the cats and not bothering us, but the three cats are clearly in distress (Liz, one of the 7 month old twins, is losing hair around her neck from so much scratching). I picked up some flea meds that go between the shoulder blades (Advantage 9 for the two 7 mo olds and Advantage 18 for the big cat) at the vet's office earlier today. In the past, I've discussed with my vet my concerns that the two kittens may lick off each others meds since they're always together and always grooming each other. I was assured that wouldn't be a problem. I'm still just a little iffy since this stuff is a pesticide. So, for those of you with additional knowledge or experience on the matter, could that be a problem? I certainly don't want them harming themselves. I'm not able to keep them isolated from each other until the meds dry and spread out. Any advice?

Thanks.

Kristin

If you follow package directions you should be fine, if they are young kittens you should have gotten kitten treatment, not cat treatment. It is far more invasive to keep your cats in fleas then to take a chance with advantage bought at the vets office. You will probably have to treat your cats for tapeworms as well. If cats have fleas, they generally have tapeworms- you can run fecals in to get them checked.