Local anesthetics (LAs) can be defined as drugs that reversibly block transmission of a nerve impulse, without affecting consciousness. Medical use of local anesthetic agents began some years after the isolation of cocaine from Peruvian coca in the 1860s. Chance discovery in 1884 by Freud while using cocaine to wean a morphine addict lead Koller to use cocaine successfully in ophthalmic surgery as a topical anesthetic. Halsted and Hall took more invasive steps by directly injecting cocaine into oral cavity nerves in order to produce anesthesia for removal of a wisdom tooth [1
However, the euphoria, subsequent addiction, and cases of mortality from the clinical use of the natural ester cocaine created a drive to the development of the less toxic newer amino esters. Einhorn's synthesis of procaine in 1905 was to dominate LA use for the next forty years, but with amino esters slow onset of action and allergen potential, the hypoallergenic amino amides gradually came into force with lignocaine appearing in 1948 and is still the most commonly used LA in dentistry.
Amino amides mepivacaine, prilocaine, and bupivacaine were all developed by 1963 and all have roles in modern dentistry. In 1969, articaine was synthesized by chemist Muschaweck, and with its potency and safety profile is now the most common LA for dental procedures in most of Europe [2
Despite these efforts, all of the amide LAs harbor varying levels of cardiovascular (CVS) and central nervous system (CNS) toxicity that is still a major complication seen today. Methods of administration have also progressed since August Bier first practiced intravenous regional anesthesia in 1908, allowing a whole limb to be anesthetized with the aid of a tourniquet and LA [3
Simultaneously, plexus anesthesia came about in the early 1900s with brachial plexus blocks for upper limb surgeries, these peripheral techniques more refined in recent decades to prolong blocks via continuous infusion regional anesthesia using catheters and pumps [4
The use of LA in neuraxial anesthesia is another significant development that began with James Corning's experiment in 1885 of spinal anesthesia on a dog [5
], but it was not used clinically until 1899 by August Bier [6
]. Lumbar epidural anesthesia came about later in 1921 by Spanish military surgeon Fidel Pages. It was popularized by the Italian surgeon Dogliotti in the 1930s [7
The idea of continuous infusion of epidural anesthesia, however, was not started until use of caudal blocks for emergency caesareans in 1942 [8
], and in more recent decades the introduction of small flexible catheters has improved safety, delivery, and duration of epidural anesthesia.