Welcome to JustAnswer, this is Dr. Christie.
Unfortunately there is no safe way to put your dog down at home.
Trying to overdose them on medication can cause more pain and suffering.
The safest and most humane way to have your dog put down is through a veterinarian.
You could call around to a few different clinics to see if there are any vets who do house calls.
This way, your dog could be put down at home.
If there is the concern of aggression at the vet's office, you can certainly discuss with the vet the option of sedation prior to the dog coming into the clinic.
Some clinics will also come out to your car (at the clinic) to perform the euthanasia.
This is not an easy decision, and if there were a safe way to put a dog or cat down at home, I would tell you.
But unfortunately there is not.