Oral administration of medication is an unacceptable method of performing euthanasia, states the American Veterinary Medical Association. The use of oral medication is limited to the administration of sedatives prior to euthanasia.
There are many more acceptable methods of euthanasia such as by injection or by inhalation of a gas, reports the American Veterinary Medical Association. Drugs that are given by mouth react differently in every dog. Some medications may be more or less effective in certain pets, and many drugs do not absorb very well through the stomach lining.
The length of time between administration and the effect of the drug is another factor, explains the American Veterinary Medical Association. Oral medications do not take effect immediately, and thus a pet's suffering is prolonged after the administration of a fatal dose of medication. Due to these factors, the administration of oral medication is not considered to be a humane method of euthanasia.