Hello, I have a year and a half old dogo argentino. Yes the large white Argentinian Mastiff! He has been scratching himself relentlessly for quite some time and when on antibiotics, it seems to only relieve it temporarily. I remember when we first gave ivermectin from the vet as tablet form, that it definately cleared up the problem. my question now is, And Im Aware, where can i get the oral form online and in what percent solution? Also how much would I give, as the dog weighs about 100 pounds. Thanks very much.