Once the dog is euthanized it takes around 2 to 3 minutes for the dog to go unconscious and die.
The dog is usually given a sedative first which causes them to go to sleep and be unaware of anything going on and then the dog is given an injection through an IV in their leg usually.
The injection through the IV that the vet introduces into their system is a drug called pentobarbital which is a seizure medication.
The medication in large doses stops the dogs heart as well as brain functions within a few minutes and then the dog is dead within at most 5 minutes of the procedure being done.
The cost to euthanize a dog ranges from as low as $50.00 to as much as $300.00 but usually you'll be paying less than $300.00 for the pet euthanasia.
If you have in home pet euthanasia the vet will charge more for the travel to and from your home so it's cheaper to have your dog or other pet taken to the vet to be euthanized.