I have a 4 year old Rat Terrier nuetered male who is mostly layed back, but can be playful at times. The problem I have with him is his obsessive chewing and scratching himself like a dog infested with fleas, but I have checked, my vet checked him and he wears a flea and tick collar. I can find no other signs of bugs, scabs or hot spots on him either, but it is really disturbing and bothersome that he is constantly digging at himself. A friend of mine who is a dog breeder and has a boarding kennel suggested dosing him with Fulvicin U/F as she has used it on some of her Poms with the same problem. I have used this on miniature horses, but it was for ringworm and my dog shows not signs of that. How safe is it to use on my dog, and in what dosage? Thanks for any help, Gary