Local anesthesia is any technique to induce the absence of sensation in a specific part of the body, generally for the aim of inducing local analgesia, i.e. local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with reduced pain and distress. In many situations, such as cesarean section, it is safer and therefore superior to general anesthesia.
A local anesthetic (LA) is a medication that causes absence of all sensation in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sensation in the entire body and causes unconsciousness. Local anesthetics are most commonly used to eliminate pain during or after surgery. When it is used on specific nerve pathways, paralysis also can be induced.
Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia and ventricular fibrillation. When used for local anaesthesia or in nerve blocks, lidocaine typically begins working within several minutes and lasts for half an hour to three hours. Lidocaine mixtures may also be applied directly to the skin or mucous membranes to numb the area. It is often used mixed with a small amount of adrenaline (epinephrine) to prolong its local effects and to decrease bleeding.
4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA because the two functional groups are attached to the benzene ring across from one another in the para position) is an organic compound with the formula H2NC6H4CO2H. PABA is a white solid, although commercial samples can appear gray. It is slightly soluble in water. It consists of a benzene ring substituted with amino and carboxyl groups. The compound occurs extensively in the natural world.
Benzocaine, sold under the brand name Orajel amongst others, is a local anesthetic, belonging to the amino ester drug class, commonly used as a topical painkiller or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments such as products for oral ulcers. It is combined with antipyrine to form A/B ear drops. In the US, products containing benzocaine for oral application are contraindicated in children younger than two years old. In the European Union, the contraindication applies to children under 12 years of age.
An anesthetic or anaesthetic is a drug used to induce anesthesia — in other words, to result in a temporary loss of sensation or awareness. They may be divided into two broad classes: general anesthetics, which result in a reversible loss of consciousness, and local anesthetics, which cause a reversible loss of sensation for a limited region of the body without necessarily affecting consciousness.
Pseudocholinesterase deficiency is an autosomal recessive inherited blood plasma enzyme abnormality in which the body's production of butyrylcholinesterase is impaired. People who have this abnormality may be sensitive to certain anesthetic drugs, including the muscle relaxants succinylcholine and mivacurium as well as other ester local anesthetics.
Infiltration analgesia is deposition of an analgesic (pain-relieving) drug close to the apex of a tooth so that it can diffuse to reach the nerve entering the apical foramina. It is the most routinely used in dental local treatment.
Benzonatate, sold under the brand name Tessalon among others, is a medication that is used for the symptomatic relief of cough. A 2023 systematic review found that there is inadequate evidence to support the effectiveness and safety of benzonatate for cough and highlighted rising safety concerns. Benzonatate is taken by mouth. Effects generally begin within 20 minutes and last 3 to 8 hours.
Bupivacaine, marketed under the brand name Marcaine among others, is a medication used to decrease sensation in a specific small area. In nerve blocks, it is injected around a nerve that supplies the area, or into the spinal canal's epidural space. It is available mixed with a small amount of epinephrine to increase the duration of its action. It typically begins working within 15 minutes and lasts for 2 to 8 hours.
Phentolamine, sold under the brand name Regitine among others, is a reversible nonselective α-adrenergic antagonist.
Methohexital or methohexitone is a drug which is a barbiturate derivative. It is classified as short-acting, and has a rapid onset of action. It is similar in its effects to sodium thiopental, a drug with which it competed in the market for anesthetics.
Chloroprocaine is a local anesthetic given by injection during surgical procedures and labor and delivery. Chloroprocaine vasodilates; this is in contrast to cocaine which vasoconstricts. Chloroprocaine is an ester anesthetic.
Alfred Einhorn was a German chemist most notable for first synthesizing procaine in 1905 which he patented under the name Novocain. Until that time the primary anesthetic in use was cocaine, however its undesirable side effects led scientists to seek out newer anesthetic drugs. Novocain was found to be comparatively safe and effective, although its anesthetic effects were weaker than cocaine and some patients proved highly allergic. However, none of the other anesthetics developed during this period proved more effective and Novocain quickly became the standard local anesthesia. Although its use has largely been replaced by lidocaine, it is still in use today, most frequently in dentistry.
Butyrylcholinesterase, also known asBChE, BuChE, BuChase, pseudocholinesterase, or plasma (cholin)esterase, is a nonspecific cholinesterase enzyme that hydrolyses many different choline-based esters. In humans, it is made in the liver, found mainly in blood plasma, and encoded by the BCHE gene.
Dental anesthesia is the application of anesthesia to dentistry. It includes local anesthetics, sedation, and general anesthesia.
Amino esters are a class of local anesthetics. They are named for their ester bond and are unlike amide local anaesthetics.
Dimethocaine, also known as DMC or larocaine, is a compound with a stimulatory effect. This effect resembles that of cocaine, although dimethocaine appears to be less potent. Just like cocaine, dimethocaine is addictive due to its stimulation of the reward pathway in the brain. However, dimethocaine is a legal cocaine replacement in some countries and is even listed by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) under the category “synthetic cocaine derivatives”. The structure of dimethocaine, being a 4-aminobenzoic acid ester, resembles that of procaine. It is found as a white powder at room temperature.
Nitrobenzoic acids are derivatives of benzoic acid. Two are commercially important. They are about ten times more acidic than the parent benzoic acid.
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