I would definitely suspect they are having a reaction to it and would try another. Here are the side effects for Interceptor.
What are the side effects
Side effects of Interceptor are rare although some animals may exhibit depression, drowsiness, vomiting, loss of appetite, diarrhea, hypersalivation, seizures and weakness.
What special precautions are there
This medication should not be used in animals allergic to it. |