Princess has been dealing with fleas & flea allergies. We did a month of Frontline & she still itched like crazy & had the dang things. I wanted to switch to something else but my vet really believes in Frontline so I bought another dose along with Capstar-it's a pill that kills any live fleas on the pup for 24 hours. After doing that she was itch/flea free for just about a week, then I repeated the Capstar & she's felt relief again. I bought one pill which was quartered up for her (8lbs),$7.00, & will probably give them weekly if she starts itching until the apt. is free of them. The vet said the Frontline has to be used for 3-6 months non-stop on all animals in the home to kill the population off.
Long story short, this is the second month & I'm seeing results. That may or may not be due to adding the Capstar. Good luck.