Anesthetic agents are a class of medicine that can make animals temporarily imperceptive, especially at pain, in order to facilitate surgery. They are divided into two types, general anaesthetic and local anesthetics.
General anesthetics can be divided by administration into:
① inhalation anesthetics, such as ether, halothane, methoxyflurane, cyclopropane and nitrous oxide, etc.
② intravenous anesthetics such as chlo-ral hydrate, barbitals and ketamine, etc. Ketamine is also known as dissociative anaesthetic. When the body is anesthetized with it, it will enter a special state of separation of consciousness and feeling.
Local anesthetic is used for surface anesthesia, infiltrating anesthesia, conduction anesthesia and spinal anesthesia, where procaine, di-caine and lidocaine are in common use.