Local anesthetic
Local anesthetic (LA) is a medication that causes reversible absence of pain sensation, although other senses are often affected as well. Also, when it is used on specific nerve pathways (local anesthetic nerve block), paralysis (loss of muscle power) can be achieved as well.
Clinical local anesthetics belong to one of two classes: aminoamide and aminoester local anesthetics. Synthetic local anesthetics are structurally related to cocaine. They differ from cocaine mainly in that they have a very low abuse potential and do not produce hypertension or (with few exceptions) vasoconstriction.
Local anesthetics are used in various techniques of local anesthesia such as:
Topical anesthesia (surface)
Infiltration
Plexus block
Epidural (extradural) block
Spinal anesthesia (subarachnoid block)
Medical uses
Acute pain
Acute pain may occur due to trauma, surgery, infection, disruption of blood circulation or many other conditions in which there is tissue injury. In a medical setting it is usually desirable to alleviate pain when its warning function is no longer needed. Besides improving patient comfort, pain therapy can also reduce harmful physiological consequences of untreated pain.