You could try supplementing your choice with natural methods to make it more effective. The things that I find work well as flea deterents (although in some areas with some dogs they will not be enough alone) are:
- garlic supplements (I use Grrr-Lick Garlic snacks and Only Natural Brewer's Yeast and Garlic Tablets)
- a little apple cider vinegar in the drinking water
- all things NEEM, including shampoo, spray, and essential oil combos with NEEM oil in them (I use Ark Naturals shampoo and spray, Doc Ackerman's Botanical Citronella shampoo, and Only Natural essential oil blend)
- diatomaceous earth on carpet and sleep areas (you spread it on and then use a broom to work it into the fiber, and then vaccuum it up three days later) plus there is pet-grade d.e. that you can put directly on your pet. It's totally safe for all mammals, and works by dehydrating insects.
- on a thread about natural flea prevention, cshellenberger suggested using nematodes in the yard: "They are a biological control, microscopic worms that eat flea larvae. You can get them at nurseries or online."
I use natural methods for flea deterence, and then when I occasionally get fleas I use frontline. Depending on your situation, though, you may need to use a medicine all the time and just use natural methods to help on top of that.
I wrote about this in another thread, but advantix has permethrin as the main ingredient, which is a known dog and cat killer. (Same chemical as in Bio Spot.) So I would seriously doubt that it is less reactive than Frontline...