Final answer:
Barbiturates, specifically drugs like pentobarbital, are commonly used for euthanasia due to their ability to induce a painless and rapid onset of coma leading to death, and are administered by injection.
Step-by-step explanation:
The drug commonly used for euthanasia is a barbiturate. Barbiturates are central nervous system (CNS) depressants, and a specific type of barbiturate, such as pentobarbital, is frequently used to induce euthanasia in animals and is also used in human euthanasia where it is legal. These drugs are chosen because of their ability to induce coma rapidly and without causing pain, which eventually leads to death.
While morphine is primarily used to manage pain without affecting consciousness, acepromazine is a tranquilizer used in veterinary medicine, and telazol is a combination of a dissociative anesthetic and a sedative used for anesthesia, particularly in animals. None of them are primarily indicated or widely used for euthanasia. In contrast, barbiturates like pentobarbital are the drugs of choice for this purpose, and they are administered via injection to ensure rapid and reliable effects.