I've not had any experience with this medication (actually had to consult the Google), but you should talk to your vet about what what you've observed, and possibly have it reported to the company. If I remember correctly, he has a of of herding breed in him? Are you sure that the Embark test came back as clear for the MDR1 gene mutation? It might be worthwhile to have another lab run just the MDR1 test. GenSol, VetGen, and Vetnostics all do the test as a stand-alone.