My indoor only kitty, Miss Scarlet, ended up with fleas this summer - they were very bad here. I think they came in on our shoes or ???
Anyway, I don't like to use toxic chemicals like that in Advantage or Frontline. While they are very effective, they can cause reactions in some kitties. What I used is a product called Flea Busters. There is another one very similar but I forget what it is called.
Flea Busters is a borax product that you sweep into the carpet and cracks in the floor and it is supposed to have electrostatic properties that keep it in the carpets/cracks for 9-15 MONTHS. It is cheaper than the monthly application of the toxic chemicals.
You do need to treat the ENTIRE house and preferably use something outside also. It a bit of a job to sweep into most plush carpets but wood, ceramic and other hard surfaces just take a couple of minutes.
Email me privately if you want more info: planosmith@yahoo.com
I was not able to find it locally but did find it on line with "free" shipping.
Good luck and let us know what you decide to use and how it works.

Betty, =^..^=(Scarlet) and Angel =^ .^=(Honeycomb)