Suxamethonium chloride, also known as suxamethonium or succinylcholine, or simply sux by medical abbreviation, is a medication used to cause short-term paralysis as part of general anesthesia. This is done to help with tracheal intubation or electroconvulsive therapy. It is given either by injection into a vein or muscle. When used in a vein onset of action is generally within one minute and effects last for up to 10 minutes.
A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics. Neuromuscular blockers act by interfering with transmission at the neuromuscular end plate and have no central nervous system (CNS) activity. They are often used during surgical procedures and in intensive care and emergency medicine to cause temporary paralysis. Spasmolytics, also known as "centrally acting" muscle relaxant, are used to alleviate musculoskeletal pain and spasms and to reduce spasticity in a variety of neurological conditions. While both neuromuscular blockers and spasmolytics are often grouped together as muscle relaxant, the term is commonly used to refer to spasmolytics only.
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.
Tubocurarine is a toxic 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. It is now rarely used as an adjunct for clinical anesthesia because safer alternatives, such as cisatracurium and rocuronium, are available.
Neuromuscular-blocking drugs block neuromuscular 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.
Rocuronium bromide is an aminosteroid non-depolarizing neuromuscular blocker or muscle relaxant used in modern anaesthesia to facilitate tracheal intubation by providing skeletal muscle relaxation, most commonly required for surgery or mechanical ventilation. It is used for standard endotracheal intubation, as well as for rapid sequence induction (RSI).
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. It can also be used to help with endotracheal intubation but suxamethonium (succinylcholine) is generally preferred if this needs to be done quickly. It is given by injection into a vein. Effects are greatest at about 4 minutes and last for up to an hour.
Gallamine triethiodide (Flaxedil) is a non-depolarising muscle relaxant. It acts by combining with the cholinergic receptor sites in muscle and competitively blocking the transmitter action of acetylcholine. Gallamine is a non-depolarising type of blocker as it binds to the acetylcholine receptor but does not have the biological activity of acetyl choline. Gallamine triethiodide has a parasympatholytic effect on the cardiac vagus nerve, which causes tachycardia and occasionally hypertension. Very high doses cause histamine release.
Sugammadex, sold under the brand name Bridion, is a medication for the reversal of neuromuscular blockade induced by rocuronium and vecuronium in general anaesthesia. It is the first selective relaxant binding agent (SRBA).
Doxacurium chloride is a neuromuscular-blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in anesthesia to provide skeletal muscle relaxation during surgery or mechanical ventilation. Unlike a number of other related skeletal muscle relaxants, it is rarely used adjunctively to facilitate endotracheal intubation.
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.
Bambuterol (INN) is a long-acting β adrenoceptor agonist (LABA) used in the treatment of asthma; it also is a prodrug of terbutaline. Commercially, the AstraZeneca pharmaceutical company produces and markets bambuterol as Bambec and Oxeol.
Butyrylcholinesterase, also known as BChE, BuChE, 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.
Laudanosine or N-methyltetrahydropapaverine is a recognized metabolite of atracurium and cisatracurium. Laudanosine decreases the seizure threshold, and thus it can induce seizures if present at sufficient threshold concentrations; however such concentrations are unlikely to be produced consequent to chemodegradable metabolism of clinically administered doses of cisatracurium or atracurium.
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.
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%.
Tetanic fade refers to the diminishing muscle twitch response from an evoked potential stimulation of muscle under the effect of either a non-depolarizing neuromuscular blocking agent, or a muscle that is under a phase 2 depolarizing neuromuscular blocking agent.
Neuromuscular blocking agents, or in abbreviation, NMBAs, are chemical agents that paralyse skeletal muscles by blocking the movement of neurotransmitter at the neuromuscular junction. They are often used during general anesthesia to optimize intubating and surgical conditions, specifically to facilitate endotracheal intubation. This class of medications helps to reduce patient movement, breathing, or ventilator dyssynchrony and allows lower insufflation pressures during laparoscopy including the generation of nerve impulses. It has several indications for use in the intense care unit. It can help reduce hoarseness in voice as well as injury to the vocal cord during intubation. In addition, it plays an important role in facilitating mechanical ventilation in patients with poor lung function. In the following section, neuromuscular blocking agent's history, usages, mechanisms, side effects, interactions and pharmacology will further be elaborated and discussed.
