I worry about this as well, but all the vets I have spoken to say that Revolution is very good. My yorkie has a compromised liver and this is the ONLY one that my vet will prescribe Miko because it is safe for him. We can't use any of the other ones no matter how good they are.
Revolution is also a heartworm preventative, so it's a 2 in 1 kind of thing.
__________________ Miko  's his Mommy |