Clinical data | |
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Trade names | Tracrium, Acurium |
Other names | Atracurium besylate |
AHFS/Drugs.com | Monograph |
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Routes of administration | IV |
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Pharmacokinetic data | |
Bioavailability | 100% (IV) |
Protein binding | 82% |
Metabolism | Hofmann elimination (retro-Michael addition) and ester hydrolysis by nonspecific esterases |
Elimination half-life | 17–21 minutes |
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ECHA InfoCard | 100.058.840 |
Chemical and physical data | |
Formula | C65H82N2O18S2 |
Molar mass | 1243.49 g·mol−1 |
3D model (JSmol) | |
Melting point | 85 to 90 °C (185 to 194 °F) |
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Atracurium besilate, also known as atracurium besylate, is a medication used in addition to other medications to provide skeletal muscle relaxation during surgery or mechanical ventilation. [1] It can also be used to help with endotracheal intubation but suxamethonium (succinylcholine) is generally preferred if this needs to be done quickly. [1] It is given by injection into a vein. [1] Effects are greatest at about 4 minutes and last for up to an hour. [1]
Common side effects include flushing of the skin and low blood pressure. [1] [2] Serious side effects may include allergic reactions; however, it has not been associated with malignant hyperthermia. [1] [2] Prolonged paralysis may occur in people with conditions like myasthenia gravis. [1] It is unclear if use in pregnancy is safe for the baby. [1] Atracurium is in the neuromuscular-blocker family of medications and is of the non-depolarizing type. [1] It works by blocking the action of acetylcholine on skeletal muscles. [1]
Atracurium was approved for medical use in the United States in 1983. [1] It is on the World Health Organization's List of Essential Medicines. [3] Atracurium is available as a generic medication. [1]
Atracurium is a medication used in addition to other medications in to provide skeletal muscle relaxation during surgery or mechanical ventilation. It can be used to help with endotracheal intubation but takes up to 2.5 minutes to result in appropriate intubating conditions. [1]
Neuromuscular-blocking agents can be classified in accordance to their duration of pharmacological action, defined as follows:
Parameter | Ultra-short Duration | Short Duration | Intermediate Duration | Long Duration |
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Clinical Duration (Time from injection to T25% recovery) | 6-8 | 12-20 | 30-45 | >60 |
Recovery Time (Time from injection to T95% recovery) | <15 | 25-30 | 50-70 | 90-180 |
Recovery Index (T25%-T75% recovery slope) | 2-3 | 6 | 10-15 | >30 |
This section needs additional citations for verification .(December 2022) |
The tetrahydroisoquinolinium class of neuromuscular blocking agents, in general, is associated with histamine release upon rapid administration of a bolus intravenous injection. [4] There are some exceptions to this rule; cisatracurium (Nimbex), for example, is one such agent that does not elicit histamine release even up to 5×ED95 doses. The liberation of histamine is a dose-dependent phenomenon such that, with increasing doses administered at the same rate, there is a greater propensity for eliciting histamine release and its ensuing sequelae. Most commonly, the histamine release following administration of these agents is associated with observable cutaneous flushing (facial face and arms, commonly), hypotension and a consequent reflex tachycardia. These sequelae are very transient effects: the total duration of the cardiovascular effects is no more than one to two minutes, while the facial flush may take around 3–4 minutes to dissipate. Because these effects are so transient, there is no reason to administer adjunctive therapy to ameliorate either the cutaneous or the cardiovascular effects.
Bronchospasm has been reported on occasion with the use of atracurium. [5] [6] [7] [8] However, this particular undesirable effect does not appear to be observed nearly as often as that seen with rapacuronium, which led to the latter's withdrawal of approval for clinical use worldwide.
The issue of bronchospasm acquired prominence in the neuromuscular-blocking agents arena after the withdrawal from clinical use of rapacuronium (Raplon - a steroidal neuromuscular-blocking agent marketed by Organon) in 2001 [9] [10] after several serious events of bronchospasm, [11] [12] including five unexplained fatalities, [13] following its administration. Bronchospasm was not an unknown phenomenon prior to rapacuronium: occasional reports of bronchospasm have been noted also with the prototypical agents, tubocurarine [14] [15] [16] and succinylcholine, [17] [18] [19] [20] [21] as well as alcuronium, [22] pancuronium, [23] [24] vecuronium, [25] [26] and gallamine. [27]
Seizures rarely occur. [1]
Because atracurium undergoes Hofmann elimination as a primary route of chemodegradation, one of the major metabolites from this process is laudanosine, a tertiary amino alkaloid reported to be a modest CNS stimulant with epileptogenic activity [28] and cardiovascular effects such a hypotension and bradycardia. [29] As part of the then fierce marketing battle between the competing pharmaceutical companies (Burroughs Wellcome Co. and Organon, Inc.) with their respective products, erroneous information was quickly and subtly disseminated very shortly after the clinical introduction of atracurium that the clinical use of atracurium was likely to result in a terrible tragedy because of the significant clinical hazard by way of frank seizures induced by the laudanosine by-product [28] - the posited hypothesis being that the laudanosine produced from the chemodegradation of parent atracurium would cross the blood–brain barrier in sufficiently high enough concentrations that lead to epileptogenic foci. [30] Fortunately, both for the public and for atracurium, rapid initial investigations irrefutably failed to find any overt or EEG evidence for a connection between atracurium administration and epileptogenic activity. [31] [32] Indeed, because laudanosine is cleared primarily via renal excretion, a cat study modelling anephric patients went so far as to corroborate that EEG changes, when observed, were evident only at plasma concentrations 8 to 10 times greater than those observed in humans during infusions of atracurium. [33] Thus, the cat study predicted that, following atracurium administration in an anephric patient, laudanosine accumulation and related CNS or cardiovascular toxicity were unlikely - a prediction that correlated very well with a study in patients with kidney failure and undergoing cadaveric renal transplantation. [34] Furthermore, almost a decade later, work by Cardone et al.. [35] confirmed that, in fact, it is the steroidal neuromuscular-blocking agents pancuronium and vecuronium that, when introduced directly into the CNS, were likely to cause acute excitement and seizures, owing to accumulation of cytosolic calcium caused by activation of acetylcholine receptor ion channels. Unlike the two steroidal agents, neither atracurium nor laudanosine caused such accumulation of intracellular calcium. Just over two decades later with availability of atracurium, there is little doubt that laudanosine accumulation and related toxicity will likely never be seen with the doses of atracurium that are generally used. [29]
Laudanosine is also a metabolite of cisatracurium that, because of its identical structure to atracurium, undergoes chemodegradation via Hofmann elimination in vivo. Plasma concentrations of laudanosine generated are lower when cisatracurium is used. [29]
Atracurium is susceptible to degradation by Hofmann elimination and ester hydrolysis as components of the in vivo metabolic processes. [36] [37] The initial in vitro studies appeared to indicate a major role for ester hydrolysis [36] but, with accumulation of clinical data over time, the preponderance of evidence indicated that Hofmann elimination at physiological pH is the major degradation pathway [37] vindicating the premise for the design of atracurium to undergo an organ-independent metabolism. [38]
Hofmann elimination is a temperature- and pH-dependent process, and therefore atracurium's rate of degradation in vivo is highly influenced by body pH and temperature: An increase in body pH favors the elimination process, [39] [40] whereas a decrease in temperature slows down the process. [38] Otherwise, the breakdown process is unaffected by the level of plasma esterase activity, obesity, [41] age, [42] or by the status of renal [43] [44] [45] [46] or hepatic function. [47] On the other hand, excretion of the metabolite, laudanosine, and, to a small extent, atracurium itself is dependent on hepatic and renal functions that tend to be less efficient in the elderly population. [42] [45] The pharmaceutical presentation is a mixture of all ten possible stereoisomers. Although there are four stereocentres, which could give 16 structures, there is a plane of symmetry running through the centre of the diester bridge, and so 6 meso structures (structures that can be superimposed by having the opposite configuration then 180° rotation) are formed. This reduces the number from sixteen to ten. There are three cis-cis isomers (an enantiomeric pair and a meso structure), four cis-trans isomers (two enantiomeric pairs), and three trans-trans isomers (an enantiomeric pair and a meso structure). The proportions of cis−cis, cis−trans, and trans−trans isomers are in the ratio of 10.5 :6.2 :1. [cis-cis isomers ≈ 58% cis-trans isomers ≈ 36% trans-trans isomers ≈ 6%]. One of the three cis-cis structures is marketed as a single-isomer preparation, cisatracurium (trade name Nimbex); it has the configuration 1R, 2R, 1′R, 2′R at the four stereocentres. The beta-blocking drug nebivolol has ten similar structures with 4 stereocentres and a plane of symmetry, but only two are presented in the pharmaceutical preparation.
Atracurium besilate was first made in 1974 by George H. Dewar, [48] a pharmacist and a medicinal chemistry doctoral candidate in John B. Stenlake's medicinal chemistry research group in the Department of Pharmacy at Strathclyde University, Scotland. Dewar first named this compound "33A74" [48] before its eventual emergence in the clinic as atracurium. Atracurium was the culmination of a rational approach to drug design to produce the first non-depolarizing non-steroidal skeletal muscle relaxant that undergoes chemodegradation in vivo. The term chemodegradation was coined by Roger D. Waigh, Ph.D., [49] also a pharmacist and a postdoctoral researcher in Stenlake's research group. Atracurium was licensed by Strathclyde University to the Wellcome Foundation UK, which developed the drug (then known as BW 33A [50] ) and its introduction to first human trials in 1979, [40] [51] and then eventually to its first introduction (as a mixture of all ten stereoisomers [52] ) into clinical anesthetic practice in the UK, in 1983, under the tradename of Tracrium.
The premise to the design of atracurium and several of its congeners stemmed from the knowledge that a bis-quaternary structure is essential for neuromuscular-blocking activity: ideally, therefore, a chemical entity devoid of this bis-quaternary structure via susceptibility to inactive breakdown products by enzymic-independent processes would prove to be invaluable in the clinical use of a drug with a predictable onset and duration of action. Hofmann elimination provided precisely this basis: It is a chemical process in which a suitably activated quaternary ammonium compound can be degraded by the mildly alkaline conditions present at physiological pH and temperature. [53] In effect, Hofmann elimination is a retro-Michael addition chemical process. It is important to note here that the physiological process of Hofmann elimination differs from the non-physiological Hofmann degradation process: the latter is a chemical reaction in which a quaternary ammonium hydroxide solid salt is heated to 100 °C, or an aqueous solution of the salt is boiled. Regardless of which Hofmann process is referenced, the end-products in both situations will be the same: an alkene and a tertiary amine.
The approach to utilizing Hofmann elimination as a means to promoting biodegradation had its roots in much earlier observations that the quaternary alkaloid petaline (obtained from the Lebanese plant Leontice leontopetalum) readily underwent facile Hofmann elimination to a tertiary amine called leonticine upon passage through a basic (as opposed to an acidic) ion-exchange resin. [54] Stenlake's research group advanced this concept by systematically synthesizing numerous quaternary ammonium β-aminoesters [55] [56] [57] [58] and β-aminoketones [59] and evaluated them for skeletal muscle relaxant activity: one of these compounds, [51] [57] initially labelled as 33A74, [48] [60] eventually led to further clinical development, and came to be known as atracurium.
Isoflurane, sold under the brand name Forane among others, is a general anesthetic. It can be used to start or maintain anesthesia; however, other medications are often used to start anesthesia, due to airway irritation with isoflurane. Isoflurane is given via inhalation.
Sevoflurane, sold under the brand name Sevorane, among others, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used as an inhalational anaesthetic for induction and maintenance of general anesthesia. After desflurane, it is the most volatile anesthetic with the fastest onset. While its offset may be faster than agents other than desflurane in a few circumstances, its offset is more often similar to that of the much older agent isoflurane. While sevoflurane is only half as soluble as isoflurane in blood, the tissue blood partition coefficients of isoflurane and sevoflurane are quite similar. For example, in the muscle group: isoflurane 2.62 vs. sevoflurane 2.57. In the fat group: isoflurane 52 vs. sevoflurane 50. As a result, the longer the case, the more similar will be the emergence times for sevoflurane and isoflurane.
Awareness under anesthesia, also referred to as intraoperative awareness or accidental awareness during general anesthesia (AAGA), is a rare complication of general anesthesia where patients regain varying levels of consciousness during their surgical procedures. While anesthesia awareness is possible without resulting in any long-term memory of the experience, it is also possible for victims to have awareness with explicit recall, where they can remember the events related to their surgery.
Bispectral index (BIS) is one of several technologies used to monitor depth of anesthesia. BIS monitors are used to supplement Guedel's classification system for determining depth of anesthesia. Titrating anesthetic agents to a specific bispectral index during general anesthesia in adults allows the anesthetist to adjust the amount of anesthetic agent to the needs of the patient, possibly resulting in a more rapid emergence from anesthesia. Use of the BIS monitor could reduce the incidence of intraoperative awareness during anaesthesia. The exact details of the algorithm used to create the BIS index have not been disclosed by the company that developed it.
Tubocurarine is a toxic benzylisoquinoline alkaloid historically known for its use as an arrow poison. In the mid-1900s, it was used in conjunction with an anesthetic to provide skeletal muscle relaxation during surgery or mechanical ventilation. Safer alternatives, such as cisatracurium and rocuronium, have largely replaced it as an adjunct for clinical anesthesia and it is now rarely used.
Minimum alveolar concentration or MAC is the concentration, often expressed as a percentage by volume, of a vapour in the alveoli of the lungs that is needed to prevent movement in 50% of subjects in response to surgical (pain) stimulus. MAC is used to compare the strengths, or potency, of anaesthetic vapours. The concept of MAC was first introduced in 1965.
Neuromuscular-blocking drugs, or Neuromuscular blocking agents (NMBAs), block transmission at the neuromuscular junction, causing paralysis of the affected skeletal muscles. This is accomplished via their action on the post-synaptic acetylcholine (Nm) receptors.
Trimetaphan camsilate (INN) or trimethaphan camsylate (USAN), trade name Arfonad, is a sympatholytic drug used in rare circumstances to lower blood pressure.
Entropy monitoring is a method of assessing the effect of certain anaesthetic drugs on the brain's EEG. It was commercially developed by Datex-Ohmeda, which is now part of GE Healthcare.
Mivacurium chloride is a short-duration non-depolarizing neuromuscular-blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.
Cisatracurium besilate is a bisbenzyltetrahydroisoquinolinium that has effect as a neuromuscular-blocking drug non-depolarizing neuromuscular-blocking drugs, used adjunctively in anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. It shows intermediate duration of action. Cisatracurium is one of the ten isomers of the parent molecule, atracurium. Moreover, cisatracurium represents approximately 15% of the atracurium mixture.
Selective relaxant binding agents (SRBAs) are a new class of drugs that selectively encapsulates and binds neuromuscular blocking agents (NMBAs). The first drug introduction of an SRBA is sugammadex.. SRBAs exert a chelating action that effectively terminates an NMBA ability to bind to nicotinic receptors.
Dogliotti's principle is a principle in epidural anaesthesia first described by Professor Achille Mario Dogliotti in 1933. It is a method for the identification of the epidural space, a potential space. As a needle is advanced through the ligamentum flavum, to the epidural space, with constant pressure applied to the piston of a syringe, loss of resistance occurs once the needle enters the epidural space due to the change in pressure. The identification of this space, allows subsequent administration of epidural anaesthesia, a technique used primarily for analgesia during childbirth.
The Outcomes Research Consortium is an international clinical research group that focuses on the perioperative period, along with critical care and pain management. The Consortium's aim is to improve the quality of care for surgical, critical care, and chronic pain patients and to "Provide the evidence for evidence-based practice." Members of the Consortium are especially interested in testing simple, low-risk, and inexpensive treatments that have the potential to markedly improve patients' surgical experiences.
Gantacurium chloride is a new experimental neuromuscular blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in surgical anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. Gantacurium is not yet available for widespread clinical use: it is currently undergoing Phase III clinical development.
Laudexium metilsulfate is a neuromuscular blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in surgical anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.
BW A444U was an experimental neuromuscular blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, intended to be used adjunctively in surgical anesthesia to facilitate endotracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation. It was synthesized and developed in the early 1980s.
Postoperative residual curarization (PORC) or residual neuromuscular blockade (RNMB) is a residual paresis after emergence from general anesthesia that may occur with the use of neuromuscular-blocking drugs. Today residual neuromuscular blockade is defined as a train of four ratio of less than 0.9 when measuring the response to ulnar nerve stimulation at the adductor pollicis muscle using mechanomyography or electromyography. A meta-analysis reported that the incidence of residual neuromuscular paralysis was 41% in patients receiving intermediate neuromuscular blocking agents during anaesthesia. It is possible that > 100,000 patients annually in the USA alone, are at risk of adverse events associated with undetected residual neuromuscular blockade. Neuromuscular function monitoring and the use of the appropriate dosage of sugammadex to reverse blockade produced by rocuronium can reduce the incidence of postoperative residual curarization. In this study, with usual care group receiving reversal with neostigmine resulted in a residual blockade rate of 43%.
Neuromuscular drugs are chemical agents that are used to alter the transmission of nerve impulses to muscles, causing effects such as temporary paralysis of targeted skeletal muscles. Most neuromuscular drugs are available as quaternary ammonium compounds which are derived from acetylcholine (ACh). This allows neuromuscular drugs to act on multiple sites at neuromuscular junctions, mainly as antagonists or agonists of post-junctional nicotinic receptors. Neuromuscular drugs are classified into four main groups, depolarizing neuromuscular blockers, non-depolarizing neuromuscular blockers, acetylcholinesterase inhibitors, and butyrylcholinesterase inhibitors.
Paravertebral block is a technique used in medicine in order to ease chest pain. An analgetic agent, usually Bupivacaine or morphine, is injected into a narrow space that lies next to the spine. A fine tube is left in place in order to re-administer the local anesthetic whenever necessary. Complications of the paravertebral block are rare. They include vascular or lung injury, hypotension and pneumothorax. Paravertebral block is used in thoracic surgery, general surgery.