Interceptor Plus for Dogs is one of the most popular drugs in the pharmaceutical market and has very few side effects when the drug is applied as per the normal dosage. But if by any chance you notice any abnormality in your pet, you must consult your veterinarian for further advice. The side effects can include weakness, vomiting, diarrhea, salivation, dizziness, depression, anorexia, lethargy, convulsions, and ataxia. Some other side effects may also occur.