Ask a Dog Vet and Get Answers to Your Dog Health Questions
Insulin overdose would be a horrible death.
Do you have any large animal/horse/cattle vets in the area?
The word euthanize literally means painless death.... An insulin overdose will kill your dog, so will antifreeze, snail bait, rat poison, or any assortment of lethal toxins. But it will not euthanize your dog.