Good for you, with the cat rescues!
I personally always swear by Frontline Plus. I've taken in strays in pretty bad condition (fleas and otherwise) and I've never had it fail me or anyone I know.
One thing you can give your kitty, in addition to flea meds, are garlic tablets. They are actually quite effective at keeping fleas at bay (and mosquitoes too). I guess the buggies don't like the taste! I've known people to use the garlic exclusively, for less serious infestations, with good results.
Of course, the constant vacuuming and cleaning is necessary too - oh well!
Since she's overweight, have you considered changing her diet? You might not have to put her on a "diet". She might simply not be processing her food properly.
Cats keep eating until their body recognizes specific vitamins and nutrients that they need - they don't recognize fullness the same way we do. So, if they are not getting needed nutrition or are not digesting properly, they often just keep going!
You might want to consider a human grade pet food (canned and dry) - grain free, low in sugars, soy free, etc. You can google human grade cat food and see what you find or you can look for By Nature's Organics, which is great. Also, a powdered digestive enzyme, added to her food, will help her process anything in her food that she might not be digesting properly.
Good luck!
Thanks. I have been vacuuming like crazy. I threw all the cats bedding in the garbage. I combed Breeanna today and found no fleas. Our other cat Jingles had a bath at the Vet and they found no fleas. Hopefully, we are getting a handle on the fleas. We have four cats. Recently I adopted Breeanna from the animal shelter and Princess who was given up by a family also. With this economy lots of cats are roaming around without a home in our area. We are at our city limit of four cats. Thanks again for your comment.
At this point, you might need to wash all the bedding and vacuum really frequently. Vacuum the crevices and under furniture and all furniture material. Take the material that was vacuumed up out to the trash immediately. Frontline and Advantage are products I use on my 2 indoor cats. I know we'll bring a few fleas in from the outdoors and need to reapply the flea medicine to our cats every once in awhile for control. As the comment above says, I've had "dud" medicine too where the product isn't working. Good luck with your kitty.
Yes, I've also heard good things about Revolution. If you don't want to go the injectable route, you can also try Advantage. I personally use Advantage,(well not me-my kitty) LOL With those spot treatments Advantage and Frontline, you'll sometimes find "duds" that just don't work! You coud also try another one to give it a chance. Trust me-I've come across plenty of duds! Boy, do they ever make me mad!!!!!
Have you tried Revolution? It might have a different name in the USA but it gets rid of fleas and ticks. It's injected just under the cat's skin. We've been using it and it works.