General Description
Fine white powder.
Air & Water Reactions
Water soluble.
Fire Hazard
Flash point data for this chemical are not available. SUXAMETHONIUM DICHLORIDE is probably combustible.
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
Uses
A neuromuscular blocking agent. Muscle relaxant (skeletal).
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.
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.
