Common side effects of the medication include sedation and a dry skin and haircoat. Serious side effects include low blood pressure, decreased body temperature, elevation of blood glucose, dilated pupils, slow heart rate, slowed intestinal rate, ataxia, prolonged sedation, vasoconstriction, vomiting, diarrhea, and seizures. Death may occur. toxic dose depends on the amount ingested, the size of your dog and the tolerance to Amitraz. i would recommend taking him to the vet immediately just in case.