Posted : 12/12/2009 11:27:33 PM
As I said above -- it's systemic. I won't use ANYTHING systemic on my dogs -- first off it makes NO sense. Why use a flea preparation that the flea has to BITE the dog to die. And there has to be some further chemical that causes it to linger in the body because ivermectin is a 24 hour drug.
Advantage and Frontline and Vectra stay topical -- they either pool in the oil glands/hair follicles (Frontline and Vectra) or Advantage "crystalizes" over the skin -- but they don't go into the bloodstream.
The only way ivermectin would kill a parasite is if it were in the bloodstream. That's how it works -- when the blood-feasting parasite 'bites' the dog the ivermectin crosses the semi-permeable brain membrane of the parasite and it disrupts the nervous system SO totally that it causes the parasite to die.
THAT is exactly why it is so dangerous to some breeds of dogs (many herding breeds, Irish Water Spaniels. Whippets, and others) -- it crosses the semi-permeable brain membrane of the DOG and it disrupts the nervous system and can cause death in a sensitive animal.
Ivermectin is a good drug for certain breeds ... BUT altering it so it stays in the body that way? Man -- that would make me run for the hills.