My 14 week old Yorkie, Bella, has thrown up multiple times late this afternoon and this evening. I gave her her first month's dose of heartworm medicine this morning, which she had no trouble gobbling down after it was mixed in with some wet puppy food. When I came home from class about an hour and a half later I saw that she had thrown up. I called the vet as soon as I saw it, but they were very rude and would only tell me to "try a different kind." That sure was helpful. This is my first puppy, and now that she's thrown up about 4 or 5 times since then I'm getting more concerned. The brand of heartworm medicine is Tri-Heart Plus, and I was told that she could have it at this age. The vet assistant didn't ask how old she was, her breed, what brand the medicine was, or anything else I thought might be relevant and was prepared to answer. If the solution really is that we just need to try a different brand of medicine that's fine, but I'm just a worried new mommy and would like some additional information.