Anesthesia can be described as a temporarily induced loss of bodily sensation or awareness. In the context of substance use, it refers specifically to the blocking of transmission of nerve impulses between a targeted part of the body and the central nervous system, causing loss of sensation in the targeted body part (which can also extend to the entire body). A person under regional or local anesthesia remains conscious unless general anaesthesia or sedation is administered at the same time.
- Local blockade inhibits sensory perception in an isolated part of the body, such as numbing a tooth for dental work or administering a nerve block to inhibit sensation in an entire limb.
- Central, or neuraxial, blockade administers the anesthetic in the region of the central nervous system itself, suppressing incoming sensation from outside the area of the block.