local anesthetics

局所麻酔薬

WordNet

1. relating to or applicable to or concerned with the administration of a city or town or district rather than a larger area; "local taxes"; "local authorities"
2. public transport consisting of a bus or train that stops at all stations or stops; "the local seemed to take forever to get to New York"
3. affecting only a restricted part or area of the body; "local anesthesia"
4. of or belonging to or characteristic of a particular locality or neighborhood; "local customs"; "local schools"; "the local citizens"; "a local point of view"; "local outbreaks of flu"; "a local bus line"
5. a drug that causes temporary loss of bodily sensations (同)anaesthetic, anesthetic_agent, anaesthetic agent
6. characterized by insensibility; "the young girls are in a state of possession--blind and deaf and anesthetic"; "an anesthetic state" (同)anaesthetic

PrepTutorEJDIC

1. 『一地方の』,ある土地の,(特に)自分の住んでいる土地の;地方に特有な / (全体からみて)『部分的な』,局部の,狭い部分の / 《米》各駅停車の / 《話》《しばしば複数形で》その土地に住んでいる人々 / 《米話》(新聞の)地方記事 / 《話》(各駅停車の)列車,電車,バス / 《米》(労働組合などの)支部
2. 低カロリーの

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/05/14 17:57:16」(JST)

wiki en

[Wiki en表示]

For the novel by Günter Grass, see Local Anaesthetic (novel).

Structure

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)

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.

Acute pain can often be managed using analgesics. However, conduction anesthesia may be preferable because of superior pain control and fewer side effects. For purposes of pain therapy, local anesthetic drugs are often given by repeated injection or continuous infusion through a catheter. Low doses of local anesthetic drugs can be sufficient so that muscle weakness does not occur and patients may be mobilized.

Some typical uses of conduction anesthesia for acute pain are:

• Labor pain (epidural anesthesia, pudendal nerve blocks)
• Postoperative pain (peripheral nerve blocks, epidural anesthesia)
• Trauma (peripheral nerve blocks, intravenous regional anesthesia, epidural anesthesia)

Chronic pain

Chronic pain is a complex and often serious condition that requires diagnosis and treatment by an expert in pain medicine. Local anesthetics can be applied repeatedly or continuously for prolonged periods to relieve chronic pain, usually in combination with medication such as opioids, NSAIDs, and anticonvulsants.

Surgery, Podiatry and Dentistry

Virtually every part of the body can be anesthetized using conduction anesthesia. However, only a limited number of techniques are in common clinical use. Sometimes conduction anesthesia is combined with general anesthesia or sedation for the patient's comfort and ease of surgery. Typical operations performed under conduction anesthesia include:

• Dentistry (surface anesthesia, infiltration anesthesia or intraligamentary anesthesia during restorative operations or extractions, regional nerve blocks during extractions and surgeries.)
• Podiatry (Cutaneous, nail avulsions, matricectomy and various other podiatric procedures)
• Eye surgery (surface anesthesia with topical anesthetics, retrobulbar block)
• ENT operations, head and neck surgery (infiltration anesthesia, field blocks, peripheral nerve blocks, plexus anesthesia)
• Shoulder and arm surgery (plexus anesthesia, intravenous regional anesthesia)
• Heart and lung surgery (epidural anesthesia combined with general anesthesia)
• Abdominal surgery (epidural/spinal anesthesia, often combined with general anesthesia)
• Gynecological, obstetrical and urological operations (spinal/epidural anesthesia)
• Bone and joint surgery of the pelvis, hip and leg (spinal/epidural anesthesia, peripheral nerve blocks, intravenous regional anesthesia)
• Surgery of skin and peripheral blood vessels (topical anesthesia, field blocks, peripheral nerve blocks, spinal/epidural anesthesia)

Other uses

Topical anesthesia, in the form of lidocaine/prilocaine (EMLA) is most commonly used to enable relatively painless venipuncture (blood collection) and placement of intravenous cannulae. It may also be suitable for other kinds of punctures such as ascites drainage and amniocentesis.

Surface anesthesia also facilitates some endoscopic procedures such as bronchoscopy (visualization of the lower airways) or cystoscopy (visualization of the inner surface of the bladder).

Undesired effects

Localized adverse effects

The local adverse effects of anesthetic agents include neurovascular manifestations such as prolonged anesthesia (numbness) and paresthesia (tingling, feeling of "pins and needles", or strange sensations). These are symptoms of localized nerve impairment or nerve damage.

Risks

The risk of temporary or permanent nerve damage varies between different locations and types of nerve blocks.

Recovery

Permanent nerve damage after a peripheral nerve block is rare. Symptoms are very likely to resolve within a few weeks. The vast majority of those affected (92%–97%), recover within four to six weeks. 99% of these people have recovered within a year. It is estimated that between 1 in 5,000 and 1 in 30,000 nerve blocks result in some degree of permanent persistent nerve damage.

It is suggested that symptoms may continue to improve for up to 18 months following injury.

Causes

Causes of localized symptoms include:

1. neurotoxicity due to allergenic reaction,
2. excessive fluid pressure in a confined space,
3. severing of nerve fibers or support tissue with the needle/catheter,
4. injection-site hematoma that puts pressure on the nerve, or
5. injection-site infection that produces inflammatory pressure on the nerve and/or necrosis.

General adverse effects

(See also local anesthetic toxicity)

General systemic adverse effects are due to the pharmacological effects of the anesthetic agents used. The conduction of electric impulses follows a similar mechanism in peripheral nerves, the central nervous system, and the heart. The effects of local anesthetics are therefore not specific for the signal conduction in peripheral nerves. Side effects on the central nervous system and the heart may be severe and potentially fatal. However, toxicity usually occurs only at plasma levels which are rarely reached if proper anesthetic techniques are adhered to. Additionally, persons may exhibit allergenic reactions to the anesthetic compounds and may also exhibit cyanosis due to methemoglobinemia.

Central nervous system

Depending on local tissue concentrations of local anesthetics, there may be excitatory or depressant effects on the central nervous system. At lower concentrations, a relatively selective depression of inhibitory neurons results in cerebral excitation, which may lead to generalized convulsions. A profound depression of brain functions occurs at higher concentrations which may lead to coma, respiratory arrest and death. Such tissue concentrations may be due to very high plasma levels after intravenous injection of a large dose. Another possibility is direct exposure of the central nervous system through the CSF, i.e., overdose in spinal anesthesia or accidental injection into the subarachnoid space in epidural anesthesia.

Cardiovascular system

Cardiac toxicity associated with overdose of intravascular injection of local anesthetic is characterized by hypotension, atrioventricular conduction delay, idioventricular rhythms, and eventual cardiovascular collapse. Although all local anesthetics potentially shorten the myocardial refractory period, bupivacaine avidly blocks the cardiac sodium channels, thereby making it most likely to precipitate malignant arrhythmias. Even levobupivacaine and ropivacaine (single-enantiomer derivatives), developed to ameliorate cardiovascular side effects, still harbor the potential to disrupt cardiac function.

Treatment of overdose: "Lipid rescue"

There is evidence that Intralipid, a commonly available intravenous lipid emulsion, can be effective in treating severe cardiotoxicity secondary to local anesthetic overdose, including human case reports of successful use in this way ('lipid rescue').

Hypersensitivity/allergy

Adverse reactions to local anesthetics (especially the esters) are not uncommon, but true allergy is very rare. Allergic reactions to the esters is usually due to a sensitivity to their metabolite, para-aminobenzoic acid (PABA), and does not result in cross-allergy to amides. Therefore, amides can be used as alternatives in those patients. Non-allergic reactions may resemble allergy in their manifestations. In some cases, skin tests and provocative challenge may be necessary to establish a diagnosis of allergy. There are also cases of allergy to paraben derivatives, which are often added as preservatives to local anesthetic solutions.

• Stub: Allergic reactions during anesthesia

Methemoglobinemia

The systemic toxicity of prilocaine is comparatively low, however its metabolite, o-toluidine, is known to cause methemoglobinemia. As methemoglobinemia reduces the amount of hemoglobin that is available for oxygen transport, this side effect is potentially life-threatening. Therefore dose limits for prilocaine should be strictly observed. Prilocaine is not recommended for use in labor pains or infants.

Mechanism of action

All local anesthetics are membrane stabilizing drugs; they reversibly decrease the rate of depolarization and repolarization of excitable membranes (like nociceptors). Though many other drugs also have membrane stabilizing properties, not all are used as local anesthetics (propranolol, for example). Local anesthetic drugs act mainly by inhibiting sodium influx through sodium-specific ion channels in the neuronal cell membrane, in particular the so-called voltage-gated sodium channels. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is inhibited. The receptor site is thought to be located at the cytoplasmic (inner) portion of the sodium channel. Local anesthetic drugs bind more readily to sodium channels in an activated state, thus onset of neuronal blockade is faster in neurons that are rapidly firing. This is referred to as state dependent blockade.

Local anesthetics are weak bases and are usually formulated as the hydrochloride salt to render them water-soluble. At a pH equal to the protonated base's pKa, the protonated (ionized) and unprotonated (unionized) forms of the molecule exist in equimolar amounts but only the unprotonated base diffuses readily across cell membranes. Once inside the cell the local anesthetic will be in equilibrium, with the formation of the protonated (ionized form), which does not readily pass back out of the cell. This is referred to as "ion-trapping". In the protonated form, the molecule binds to the local anesthetic binding site on the inside of the ion channel near the cytoplasmic end. Most local anaesthetics work on the internal surface of the membrane - the drug has to penetrate the cell membrane, which is achieved best in the non-ionised form.

Acidosis such as caused by inflammation at a wound partly reduces the action of local anesthetics. This is partly because most of the anesthetic is ionized and therefore unable to cross the cell membrane to reach its cytoplasmic-facing site of action on the sodium channel.

All nerve fibers are sensitive to local anesthetics, but due to a combination of diameter and myelination, fibers have different sensitivities to local anesthetic blockade, termed "Differential Blockade." Type B fibers (sympathetic tone) are the most sensitive followed by Type C (Pain), Type A delta (temperature), Type A gamma (proprioception), Type A beta (sensory touch and pressure) and Type A alpha (motor). Although Type B fibers are thicker than Type C fibers, they are myelinated, and thus are blocked before the unmyelinated, thin C Fiber.

Techniques

Local anesthetics can block almost every nerve between the peripheral nerve endings and the central nervous system. The most peripheral technique is topical anesthesia to the skin or other body surface. Small and large peripheral nerves can be anesthetized individually (peripheral nerve block) or in anatomic nerve bundles (plexus anesthesia). Spinal anesthesia and epidural anesthesia merges into the central nervous system.

Injection of local anesthetics is often painful. A number of methods can be used to decrease this pain including buffering of the solution with bicarb and warming.

Clinical techniques include:

• Surface anesthesia - application of local anesthetic spray, solution or cream to the skin or a mucous membrane. The effect is short lasting and is limited to the area of contact.
• Infiltration anesthesia - injection of local anesthetic into the tissue to be anesthetized. Surface and infiltration anesthesia are collectively topical anesthesia.
• Field block - subcutaneous injection of a local anesthetic in an area bordering on the field to be anesthetized.
• Peripheral nerve block - injection of local anesthetic in the vicinity of a peripheral nerve to anesthetize that nerve's area of innervation.
• Plexus anesthesia - injection of local anesthetic in the vicinity of a nerve plexus, often inside a tissue compartment that limits the diffusion of the drug away from the intended site of action. The anesthetic effect extends to the innervation areas of several or all nerves stemming from the plexus.
• Epidural anesthesia - a local anesthetic is injected into the epidural space where it acts primarily on the spinal nerve roots. Depending on the site of injection and the volume injected, the anesthetized area varies from limited areas of the abdomen or chest to large regions of the body.
• Spinal anesthesia - a local anesthetic is injected into the cerebrospinal fluid, usually at the lumbar spine (in the lower back), where it acts on spinal nerve roots and part of the spinal cord. The resulting anesthesia usually extends from the legs to the abdomen or chest.
• Intravenous regional anesthesia (Bier's block) - blood circulation of a limb is interrupted using a tourniquet (a device similar to a blood pressure cuff), then a large volume of local anesthetic is injected into a peripheral vein. The drug fills the limb's venous system and diffuses into tissues where peripheral nerves and nerve endings are anesthetized. The anesthetic effect is limited to the area that is excluded from blood circulation and resolves quickly once circulation is restored.
• Local anesthesia of body cavities (e.g. intrapleural anesthesia, intraarticular anesthesia)

• Transincision (or Transwound) catheter anesthesia, wherein a multilumen catheter is inserted through an insicion or wound and aligned across it on the inside as the incision or wound is closed, providing continuous administration of local anesthetic along the incision or wound.

Local anesthetics in clinical use

This LA system is designed to prevent needlestick injury. A cartridge of LA fits into the disposable needle, which can be locked when not in use and can be separated from the handle

Local anesthetic solutions for injection typically consist of the following ingredients:

• The local anesthetic agent itself
• A vehicle, which is usually water-based or just sterile water
• +/- Vasoconstrictor (see below)
• Reducing agent (antioxidant), e.g. if epinephrine is used then sodium metabisulfite is used as a reducing agent
• Preservative, e.g. methylparaben
• Buffer

Esters are prone to producing allergic reactions, which may necessitate the use of an Amide. The names of each locally clinical anesthetic have the suffix "-caine". Most ester local anesthetics are metabolized by pseudocholinesterases, while amide local anesthetics are metabolized in the liver. This can be a factor in choosing an agent in patients with liver failure, although since cholinesterases are produced in the liver, physiologically (e.g. very young or very old individual) or pathologically (e.g. cirrhosis) impaired hepatic metabolism is also a consideration when using amides.

Ester local anesthetics include:

Procaine

• Benzocaine
• Chloroprocaine
• Cocaine
• Cyclomethycaine
• Dimethocaine/Larocaine
• Piperocaine
• Propoxycaine
• Procaine/Novocaine
• Proparacaine
• Tetracaine/Amethocaine

Amide anesthetics include:

Lidocaine

• Articaine
• Bupivacaine
• Cinchocaine/Dibucaine
• Etidocaine
• Levobupivacaine
• Lidocaine/Lignocaine
• Mepivacaine
• Prilocaine
• Ropivacaine
• Trimecaine

Sometime local anesthetics are combined together, e.g.:

• Lidocaine/prilocaine (EMLA, eutectic mixture of local anesthetic)
• Lidocaine/tetracaine (Rapydan)

Local anesthetic solutions for injection are sometimes mixed with vasoconstrictors (combination drug) to increase the duration of local anesthesia by constricting the blood vessels, thereby safely concentrating the anesthetic agent for an extended duration, as well as reducing hemorrhage. Because the vasoconstrictor temporarily reduces the rate at which the systemic circulation removes the local anesthetic from the area of the injection, the maximum doses of LAs when combined with a vasoconstrictor is higher compared to the same LA without any vasoconstrictor. Occasionally, cocaine is administered for this purpose. Examples include:

• Prilocaine hydrochloride and epinephrine (trade name Citanest Forte)
• Lidocaine, bupivacaine, and epinephrine (recommended final concentrations of 0.5%, 0.25% and 1:200, respectively)
• Iontocaine, consisting of lidocaine and epinephrine
• Septocaine (trade name Septodont), a combination of articaine and epinephrine

It is safe to use local anesthetic with vasoconstrictor in regions supplied by end arteries. The commonly held belief that local anaesthesia with vasoconstrictor can cause necrosis in extremities such as the nose, ears, fingers and toes due to constriction of end arteries, is invalidated, since no case of necrosis has been reported since the introduction of commercial lidocaine with epinephrine in 1948.

Naturally derived local anesthetics

• Saxitoxin
• Neosaxitoxin
• Tetrodotoxin
• Menthol
• Eugenol
• Cocaine

Naturally occurring local anesthetics not derived from cocaine are usually neurotoxins, and have the suffix -toxin in their names. [1] Unlike cocaine produced local anesthetics which are intracellular in effect, saxitoxin, neosaxitoxin & tetrodotoxin bind to the extracellular side of sodium channels.

History

It is believed that in Peru the ancient Incas used the leaves of the coca plant as a local anaesthetic in addition to its stimulant properties. It was also used for slave payment and is thought to play a role in the subsequent destruction of Incas culture when Spaniards realized the effects of chewing the coca leaves and took advantage of it. Cocaine was isolated in 1860 and first used as a local anesthetic in 1884. 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.

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.

Spinal anesthesia was first used in 1885 but not introduced into clinical practice until 1899, when August Bier subjected himself to a clinical experiment in which he observed the anesthetic effect, but also the typical side effect of postpunctural headache. Within a few years, spinal anesthesia became widely used for surgical anesthesia and was accepted as a safe and effective technique. Although atraumatic (non-cutting-tip) cannulas and modern drugs are used today, the technique has otherwise changed very little over many decades.

Epidural anesthesia by a caudal approach had been known in the early 20th century, but a well-defined technique using lumbar injection was not developed until 1921, when Fidel Pagés published his article "Anestesia Metamérica". This technique was popularized in the 1930s and 1940s by Achile Mario Dogliotti. With the advent of thin flexible catheters, continuous infusion and repeated injections have become possible, making epidural anesthesia a highly successful technique to this day. Beside its many uses for surgery, epidural anesthesia is particularly popular in obstetrics for the treatment of labor pain.

See also

• Amylocaine
• Anesthetic
• General anesthetic
• List of cocaine analogues

References

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 局所麻酔剤の浸潤 infiltration of local anesthetics
• 2. 局所麻酔剤に対するアレルギー反応 allergic reactions to local anesthetics
• 3. 末梢神経ブロックの概要 overview of peripheral nerve blocks
• 4. 麻酔および麻酔剤選択の概要 overview of anesthesia and anesthetic choices
• 5. 頸動脈内膜剥離術および頸動脈ステント留置術の麻酔 anesthesia for carotid endarterectomy and carotid stenting

English Journal

• Antioxidant's cytoprotective effects on rotator cuff tenofibroblasts exposed to aminoamide local anesthetics.

• Kim RJ1, Hah YS2, Kang JR3, Park HB4.
• Journal of orthopaedic research : official publication of the Orthopaedic Research Society.J Orthop Res.2015 Jul;33(7):1001-7. doi: 10.1002/jor.22814. Epub 2015 Apr 14.
• Local anesthetics (LA) are among the drugs most frequently used for musculoskeletal problems, in procedures ranging from diagnosis to postoperative pain control. The cytotoxicity of LA is an emerging area of concern. The purpose of this study was to determine whether cyanidin, an antioxidant, exerts
• PMID 25639557

• Manipulations of extracellular Loop 2 in α1 GlyR ultra-sensitive ethanol receptors (USERs) enhance receptor sensitivity to isoflurane, ethanol, and lidocaine, but not propofol.

• Naito A1, Muchhala KH1, Trang J1, Asatryan L2, Trudell JR3, Homanics GE4, Alkana RL1, Davies DL5.
• Neuroscience.Neuroscience.2015 Jun 25;297:68-77. doi: 10.1016/j.neuroscience.2015.03.034. Epub 2015 Mar 28.
• We recently developed ultra-sensitive ethanol receptors (USERs) as a novel tool for investigation of single receptor subunit populations sensitized to extremely low ethanol concentrations that do not affect other receptors in the nervous system. To this end, we found that mutations within the extrac
• PMID 25827497

• EMLA and Lidocaine Spray: A Comparison for Surgical Debridement in Venous Leg Ulcers.

• Cuomo R1, D'Aniello C1, Grimaldi L1, Nisi G1, Botteri G1, Zerini I1, Brandi C1.
• Advances in wound care.Adv Wound Care (New Rochelle).2015 Jun 1;4(6):358-361.
• Objective: In this study the author proposes to compare eutectic mixture of local anesthetics (EMLA) and an odontoiatric spray solution of 10% Lidocaine (Ecocain) for surgical debridement in venous leg ulcers. Approach: Fifty patients were recruited and randomly assigned into two groups (A, B). All
• PMID 26029486

Japanese Journal

• 左深頸神経叢ブロック後に一過性の著明な高血圧を示した1症例

• 日本ペインクリニック学会誌 advpub(0), 2016
• NAID 130005110398

• 経皮吸収型製剤 : 局所麻酔薬 (特集 痛み治療に関わるドラッグデリバリーシステム)

• 麻酔 64(11), 1151-1159, 2015-11
• NAID 40020641441

• 症例報告 局所麻酔薬の添加物によるアレルギーが疑われた患者の抜歯に歯科用3%メピバカインが有効であった1症例

• 広島大学歯学雑誌 = The journal of Hiroshima University Dental Society 47(1), 41-44, 2015-06
• NAID 40020535677

Related Links

• Local anesthetic - Wikipedia, the free encyclopedia

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 ...

• Local Anesthetics - E-Medicine - Medscape

19 Apr 2013 ... Local Anesthetics. Cocaine is a naturally occurring compound indigenous to the Andes Mountains, West Indies, and Java.

Related Pictures

---

★リンクテーブル★

リンク元	「局所麻酔薬」
関連記事	「local」「anesthetic」

「局所麻酔薬」

　　[★]

英

local anesthetic, local anesthetics

同

局麻薬、局所麻酔剤

関

局所麻酔、局所麻酔薬一覧

構造

• ベンゼン環とアミノ基がエステル結合でつながっている：コカイン、プロカイン、テトラカイン
• ベンゼン環とアミノ基がアミド結合でつながっている：リドカイン、メピバカイン、ジブカイン、ブピバカイン

作用機序

• 電位依存性Naチャネルに結合して膜の脱分極を抑制、神経伝達を遮断。

商品

• アナペイン
• アネステジン
• アネトカイン
• アミノ安息香酸エチル
• エムラクリーム
• オリベス
• カルボカイン
• キシロカイン
• ストロカイン
• スルカイン
• テーカイン
• テトカイン
• ニチカイン
• ネオペルカミンＳ
• パートラン
• フリードカイン
• プロカイン塩酸塩
• プロカニン
• ペルカミンエス
• ペルカミン
• ペンレス
• ポプスカイン
• マーカイン
• メドカイン
• ユーパッチ
• リドカイン
• ロカイン
• 塩プロ
• 塩酸プロカイン
• 塩酸メピバカイン

「local」

　　[★]

• adj.

• 局所性の、局所的な、局所の、局在性の、地方の、地域の

関

area、district、endemic、focal、focally、locality、localization、localized、locally、locoregional、province、region、regional、regionally、spot、topical、topically

　 　 　 　 　 　

「anesthetic」

　　[★]

• ae`nэsθe'tik
• adj.

• 麻酔による

• n.

• 麻酔薬

• ex.

• anesthetic agent

関

anaesthetic、anaesthetics、anesthetic agent、anesthetic drug、anesthetics