I have a 3lb poodle and a 5 lb yorkie and my vet said it was fine to split the dose between them, I really hate to overmedicate them if I don't have to.
You should probably ask your own vet though for your own peice of mind.
I know the breeder I bought the yorkie from said she does ths with her dogs and has never had a problelm
__________________ 
Lil Cheeky Charlie's mom  |