Succinylcholine Chloride

Description

Succinylcholine chloride is a potent relaxant of voluntary striated muscle but has little direct effect on smooth muscle. It has no anesthetic or pain-obliterating properties; therefore, immobilized animals remain completely conscious although unable to move. The duration of effect is quite brief because succinylcholine is rapidly destroyed by non-specific cholinesterases in the blood plasma and liver. Immobilization lasts five to 12 minutes in man and horses and somewhat longer in other species,with ruminants generally requiring longest recovery periods (Stowe et al. 1958).
Since the discovery of its curariform properties in 1949, succinylcholine has been widely used for immobilization of animals and in human surgical procedures. Several workers have used succinylcholine on bears (Black 1958, Knudsen 1959, Craighead et al. 1960, Troyer et al. 1961,Hornocker 1962, Mundy 1963,Pearson et al. 1968, Jonkel and Cowan 1971 and Mundy and Flook 1973).
Succinylcholine chloride is indicated as an adjunct to general anesthesia, to facilitate tracheal intubation, and to provide skeletal muscle relaxation during surgery or mechanical ventilation.

Chemical properties

Succinylcholine chloride is a white, odorless, slightly bitter powder and very soluble in water. The drug is unstable in alkaline solutions but relatively stable in acid solutions, depending upon the concentration of the solution and the storage temperature. Solutions of succinylcholine chloride should be stored under refrigeration to preserve potency.

Originator

Anectine,Glaxo Wellcome

The Uses of Succinylcholine Chloride

A neuromuscular blocking agent. Muscle relaxant (skeletal).

What are the applications of Application

Succinylcholine Chloride is a neuromuscular blocking agent

Definition

ChEBI: A chloride salt in which the negative charge of the chloride ions is balanced by succinylcholine dications.

Manufacturing Process

For the first time Fusko with coworkers synthesied the succinylcholine in 1949 year.
By the etherification of succinic acid chloroanhydride with dimethylaminoethanol hydrochloride in the presence of sodium hydroxide succinylcholine was prepared. Then the obtained succinylcholine was purified. To the succinylcholine the methylchloride was added (1:2 mols) and the succinylcholine dichloride was obtained as white powder.
The succinylcholine is used as succinylcholine diiodide. This salt may be prepeared identicaly.

brand name

Anectine (Sandoz); Quelicin (Hospira); Sucostrin (Apothecon).

Therapeutic Function

Muscle relaxant

World Health Organization (WHO)

Suxamethonium chloride is a short-acting muscle relaxant. It is used in surgery. Suxamethonium chloride is listed in the WHO Model List of Essential Drugs.

Biological Functions

Succinylcholine chloride (Anectine) is the only depolarizing- type blocker that is in widespread clinical use. It produces neuromuscular block by overstimulation, so that the end plate is unable to respond to further stimulation. Structurally, succinylcholine is equivalent to two ACh molecules joined back to back. The resulting 10- carbon atom spacing between the two quaternary ammonium heads is important for activation of the two binding sites on the AChR. Because the succinylcholine molecule is “thin,” binding to the two sites does not sterically occlude the open channel, and cations are allowed to flow and depolarize the end plate.
Neuromuscular block with succinylcholine occurs by two sequential events. An initial depolarization of the end plate produces muscle action potentials and fasciculation. Maintained depolarization past the threshold for firing produces Na channel inactivation, so that muscle action potentials cannot be generated. This is called phase I, or depolarization block. In the continued presence of succinylcholine, the membrane becomes repolarized, Na channel inactivation is reversed, and muscle membrane excitability is restored. Nonetheless, the neuromuscular block persists because of desensitization of the AChR. This is known as phase II, or desensitization block.
Although the mechanism for phase II block is not completely understood, a series of allosteric transitions in the AChR is suspected. One model to describe this has the AChR in equilibrium among four conformations: resting, active, inactive, and desensitized. Agonists stabilize the active and desensitized states, whereas antagonists tend to stabilize the resting and possibly the desensitized state.

General Description

Fine white powder.

General Description

Succinylcholine chloride,choline chloride succinate (2:1) (Anectine, Sucostrin),is a white, odorless, crystalline substance that is freely solublein water to give solutions with a pH of about 4. It isstable in acidic solutions but unstable in alkali. Aqueous solutionsshould be refrigerated to ensure stability.
Succinylcholine chloride is characterized by a very shortduration of action and a quick recovery because of its rapidhydrolysis after injection. It brings about the typical muscularparalysis caused by blocking nervous transmission at themyoneural junction. Large doses may cause temporary respiratorydepression, as with similar agents. Its action, in contrastwith that of (1)-tubocurarine, is not antagonized byneostigmine, physostigmine, or edrophonium chloride.These anticholinesterase drugs actually prolong the action ofsuccinylcholine chloride, which suggests that the drug isprobably hydrolyzed by cholinesterases. The brief durationof action of this curare-like agent is said to render an antidoteunnecessary if the proper supportive measures are available.Succinylcholine chloride has a disadvantage, however, inthat the usual antidotes cannot terminate its action promptly.

Air & Water Reactions

Water soluble.

Fire Hazard

Flash point data for SUCCINYLCHOLINE CHLORIDE are not available. SUCCINYLCHOLINE CHLORIDE is probably combustible.

Clinical Use

Succinylcholine Chloride is used as a muscle relaxant for the same indications asother curare agents. It may be used for either short or longperiods of relaxation, depending on whether one or severalinjections are given. In addition, it is suitable for continuousintravenous drip administration.
Succinylcholine chloride should not be used withthiopental sodium because of the high alkalinity of the latter.If used together, they should be administered immediatelyafter mixing; however, separate injection is preferable.

Veterinary Drugs and Treatments

Succinylcholine chloride is indicated for short-term muscle relaxation needed for surgical or diagnostic procedures, to facilitate endotracheal intubation in some species, and reducing the intensity of muscle contractions associated with electro- or pharmacological- induced convulsions. Dogs, cats, and horses are the primary veterinary species where succinylcholine chloride has been used.

Drug interactions

Potentially hazardous interactions with other drugs
Anaesthetics: increased risk of myocardial depression and bradycardia with propofol; enhanced effect with volatile liquid general anaesthetics.
Anti-arrhythmics: lidocaine and procainamide enhance muscle relaxant effect.
Antibacterials: effect enhanced by aminoglycosides, clindamycin, polymyxins, vancomycin and piperacillin.
Cardiac glycosides: increased risk of ventricular arrhythmias.

Metabolism

Suxamethonium is rapidly hydrolysed to succinylmonocholine a weak neuro-muscular blocking drug. This is metabolised to succinic acid with only a small amount excreted in the urine.