A local anesthetic (LA) is a drug that causes reversible local anesthesia, generally for the aim of having a local analgesic effect, that is, inducing absence of pain sensation, although other local 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)
