7 month old blue heeler. Have dose of worm/flea/heart worm pill yesterday. Hour later very lethargic. This morning same. Yawns a lot. Weak eyed

最佳回答：

This sounds like your pet Buster could possible be having an allergic reaction to the heart worm medication. Australian Cattle dogs are one of those breeds of dogs that can be susceptible to the active ingredient in heart worm medication, called Ivermectin. This Ivermectin sensitivity is caused by a genetic mutation in the MDR-1 gene that doesn't allow these dogs to break down Ivermectin appropriately and can lead to toxic effects. There is a test for the MDR-1 gene mutation (approx $200 test) that can be sent to the lab to see if Buster has this abnormality.

But the most immediate thing that you should consider is to have Buster checked by your veterinarian to ensure his vitals are ok and also to get him treated for a potential adverse reaction (i.e. anti-histamines +/- steroids +/- vasodilators). This should be treated right away to avoid a potentially unfavorable outcome for Buster.