A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general anesthetic. When it is used on specific nerve pathways (local anesthetic nerve block), paralysis (loss of muscle power) also can be achieved. Examples
Short Duration & Low Potency
Procaine
Chloroprocaine
Medium Duration & Potency
Lidocaine
Prilocaine
High Duration & Potency
Tetracaine
Bupivacaine
Cinchocaine
Ropivacaine
Clinical LAs belong to one of two classes: aminoamide and aminoester local anesthetics. Synthetic LAs 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. They are used in various techniques of local anesthesia such as:

Topical anesthesia (surface)
Topical administration of cream, gel, ointment, liquid, or spray of anaesthetic dissolved in DMSO or other solvents/carriers for deeper absorption
Infiltration
Brachial plexus block
Epidural (extradural) block
Spinal anesthesia (subarachnoid block)
IontophoresisThe suffix "-caine" at the ends of these medication names was extracted from the word "cocaine", because cocaine was formerly used as a local anesthetic. Medical uses
Acute pain
Acute pain may occur due to trauma, surgery, infection, disruption of blood circulation, or many other conditions in which tissue injury occurs. In a medical setting, pain alleviation is desired when its warning function is no longer needed. Besides improving patient comfort, pain therapy can also reduce harmful physiological consequences of untreated pain.Acute pain can often be managed using analgesics.
The search for a less toxic and less addictive substitute led to the development of the aminoester local anesthetics stovaine in 1903 and procaine in 1904. Since then, several synthetic local anesthetic drugs have been developed and put into clinical use, notably lidocaine in 1943, bupivacaine in 1957, and prilocaine in 1959. The invention of clinical use of local anaesthesia is credited to the Vienna School which included Sigmund Freud (1856-1939), Carl Koller (1857-1944) and Leopold Konigstein (1850-1942). They introduced local anaesthesia, using cocaine, through self-experimation on their oral mucosa before introducing it to animal or human experimentation. The Vienna school first started using cocaine as local anaesthesia in ophthalmology and it was later incorporated into ophthalmologic practice. Dr. Halsted and Dr. Hall, in the United States in 1885 described an intraoral anaesthetic technique of blocking the inferior alveolar nerve and the antero-superior dental nerve using 4% cocaine. {Shortly after the first use of cocaine for topical anesthesia, blocks on peripheral nerves were described. Brachial plexus anesthesia by percutaneous injection through axillary and supraclavicular approaches was developed in the early 20th century. The search for the most effective and least traumatic approach for plexus anesthesia and peripheral nerve blocks continues to this day. In recent decades, continuous regional anesthesia using catheters and automatic pumps has evolved as a method of pain therapy. Intravenous regional anesthesia was first described by August Bier in 1908. This technique is still in use and is remarkably safe when drugs of low systemic toxicity such as prilocaine are used.