Lysthenon^® (Solution) Instructions for Use

ATC Code

M03AB01 (Suxamethonium chloride)

Active Substance

Suxamethonium chloride (Rec.INN registered by WHO)

Clinical-Pharmacological Group

Peripherally acting depolarizing-type muscle relaxant

Pharmacotherapeutic Group

Depolarizing peripheral-acting muscle relaxant

Pharmacological Action

A short-acting peripheral depolarizing muscle relaxant. It causes blockade of neuromuscular transmission. During phase I, suxamethonium chloride interacts with n-cholinergic receptors and causes depolarization of the end plate. The process spreads to adjacent membranes, causing a generalized disorganized contraction of muscle motor units.

Since acetylcholine is not metabolized in the synapse with sufficient efficiency, the membranes remain depolarized and do not respond to additional impulses. Since maintaining muscle tone requires the arrival of repeated impulses coupled with repolarization of the end plate, spastic paralysis occurs. During phase II, with continued contact with suxamethonium chloride, the membrane is unable to depolarize again under the influence of acetylcholine. The mechanism of this process remains unclear.

After administration of suxamethonium chloride, muscle relaxation occurs in the following sequence: muscles of the fingers, eyes, legs, neck, back; then the intercostal muscles and diaphragm. Suxamethonium chloride is rapidly destroyed by plasma pseudocholinesterase, which limits the intensity and duration of the neuromuscular blockade. It does not cross the intact BBB, and there is no data on a direct effect on cerebral functions. However, Suxamethonium chloride causes indirect activation of the EEG, an increase in cerebral blood flow and intracranial pressure under conditions of weak general anesthesia.

After IV administration, the effect develops in 54-60 seconds, after IM administration – in 2-4 minutes.

The duration of action is 2-6 minutes.

Pharmacokinetics

After IV administration, it is distributed in plasma and extracellular fluid. More than 90% is hydrolyzed by plasma pseudocholinesterase to succinic acid and choline. T_1/2 is 90 seconds with a normal level of pseudocholinesterase. It is excreted by the kidneys.

Indications

Surgical interventions requiring the cessation of spontaneous respiration (endotracheal intubation, bronchoscopy) and complete muscle relaxation (gynecological, thoracic, abdominal operations; reduction of dislocations, reposition of bone fragments in fractures and other interventions). Prevention of convulsions during electroconvulsive therapy. Tetanus. Strychnine poisoning.

ICD codes

Dosage Regimen

Administer Lysthenon^® intravenously or intramuscularly. The dose, route of administration, and duration of therapy are determined individually based on the patient’s body weight, clinical indication, and age.

For adult intravenous administration, use an initial dose of 0.3 to 1.1 mg per kg of body weight. The typical dose for endotracheal intubation is 1 mg/kg. Onset of action occurs within 30 to 60 seconds, with a duration of effect lasting 2 to 6 minutes.

For prolonged muscle relaxation, administer a continuous intravenous infusion at a rate of 2.5 to 4.3 mg per minute. Alternatively, use intermittent bolus injections of 0.04 to 0.07 mg/kg. Continuously monitor neuromuscular function with a peripheral nerve stimulator to guide dosing and avoid overdose.

For intramuscular administration when IV access is unavailable, use a dose of up to 4 mg/kg. Do not exceed a total dose of 150 mg per single IM injection. Onset of action after intramuscular injection is 2 to 4 minutes.

In pediatric patients, adjust the intravenous dose carefully. For infants and young children, a slightly higher initial dose per kg of body weight may be required compared to adults. Use with extreme caution due to an increased risk of bradycardia and other cardiac arrhythmias.

For electroconvulsive therapy, administer a single IV dose of 0.3 to 0.6 mg/kg to prevent trauma from convulsions. Titrate the dose to achieve the desired level of muscle relaxation.

Reduce the dosage in patients with reduced plasma pseudocholinesterase activity, as this condition prolongs the duration of neuromuscular blockade. Conditions associated with reduced enzyme activity include severe liver disease, renal failure, malnutrition, and late pregnancy.

Avoid multiple or repeated doses in patients with severe burns, major trauma, or neuromuscular diseases due to the high risk of life-threatening hyperkalemia. Use a single, standard dose only if no hyperkalemia is present.

Premedicate with atropine or glycopyrrolate to minimize bradycardia, particularly in pediatric patients or after a second dose. Pretreatment with a non-depolarizing muscle relaxant may reduce the incidence and severity of postoperative myalgia and muscle fasciculations.

Adverse Reactions

From the immune system: frequent – sudden redness of the skin, urticaria; rare – bronchospasm; very rare – anaphylactic shock with sudden redness of the skin, including accompanied by bronchospasm and decreased blood pressure.

From metabolism very common – myoglobinemia (found in 20% of children, less often in adults) with/without muscle fasciculations; very rare – life-threatening hyperkalemia, porphyria, malignant hyperthermia with/without muscle rigidity (trismus, increased end-tidal CO₂ concentration (on capnometry)), increased body temperature, severe acidosis, hemoglobinuria.

From the organ of vision frequent – increased intraocular pressure.

From the respiratory system rare – prolonged apnea in patients with impaired plasma cholinesterase activity, laryngospasm; very rare – late respiratory failure in neuromuscular transmission disorders, laryngeal edema, pulmonary edema.

From the digestive system frequent – increased intragastric pressure (risk of regurgitation in pregnant patients, patients with hiatal hernia, gastric and intestinal atony, ascites, and abdominal tumors), increased salivation.

From the musculoskeletal system very common – muscle fasciculations, myalgia (as a result of muscle fasciculations, most often develops in the neck, shoulder girdle, chest and back); not frequent – mild trismus (up to 60 seconds); rare – muscle contractions instead of relaxation (often against the background of dystrophic myotonia or congenital myotonia), prolonged paralysis due to the development of a dual block and impaired neuromuscular transmission, which can also be a consequence of idiosyncrasy, overdose or decreased plasma cholinesterase activity; very rare – acute rhabdomyolysis with established and unestablished neuromuscular conduction disorders.

From the cardiovascular system very common – arrhythmias (more common in children), mild bradycardia (especially in children); frequent – increase or decrease in blood pressure; infrequent – tachycardia; very rare – ventricular arrhythmias, ventricular fibrillation, cardiac arrest, (due to hyperkalemia), hypercalcemia (especially in children with undiagnosed skeletal muscle diseases); heart failure as a result of anaphylactoid reactions.

From the urinary system rare – myoglobinuria and increased CPK activity, mainly in children who received Suxamethonium chloride in combination with halothane; very rare – myoglobinuria leading to renal failure, mainly in patients with diagnosed or latent muscular dystrophy.

From the nervous system frequent – increased intracranial pressure.

Contraindications

Hypersensitivity to suxamethonium chloride; tendency to malignant hyperthermia, severe burns, multiple trauma, severe abdominal infections, sepsis, prolonged immobilization, penetrating eye injury with increased intraocular pressure, increased intracranial pressure; neuromuscular conduction disorders in myotonia, poliomyelitis, amyotrophic lateral sclerosis, multiple sclerosis, all forms of muscular dystrophy, severe myasthenia; denervation leading to secondary muscle atrophy (transverse syndrome); congenital cholinesterase deficiency; lactation (breastfeeding).

With caution: heart disease, lung disease, conditions accompanied by decreased cholinesterase activity, hypothermia, hypermagnesemia, hypocalcemia, hypokalemia; pregnancy.

Use in Pregnancy and Lactation

During pregnancy, it is possible to use according to indications in cases where the expected benefit to the mother outweighs the potential risk to the fetus or infant.

If it is necessary to use during lactation, the issue of stopping breastfeeding should be decided.

An increase in the intensity and duration of the neuromuscular blockade caused by suxamethonium chloride may be secondarily due to a decrease in plasma cholinesterase activity, which is observed during pregnancy and in the postpartum period.

Use in Hepatic Impairment

Contraindicated in acute liver failure.

Use in Renal Impairment

Should be used with caution in patients with renal failure. In the absence of hyperkalemia and neuropathy in patients with renal failure, Suxamethonium chloride can be administered once in average doses, but should not be used for multiple administration or in increased doses due to the risk of hyperkalemia.

Pediatric Use

Should be used with caution in children and adolescents, due to the increased risk in this category of patients of bradycardia, tachycardia; replacement nodal rhythm and ventricular extrasystole are possible.

Special Precautions

Used in a specialized hospital department with equipment for mechanical ventilation.

In the absence of hyperkalemia and neuropathy in patients with renal failure, Suxamethonium chloride can be administered once in average doses, but should not be used for multiple administration or in increased doses due to the risk of hyperkalemia.

The use of suxamethonium chloride should be avoided in congenital and dystrophic myotonia, Duchenne muscular dystrophy.

An increase in the intensity and duration of the neuromuscular blockade caused by suxamethonium chloride may be secondarily due to a decrease in plasma cholinesterase activity, which is observed in the following diseases and conditions: tetanus, tuberculosis and other severe or chronic infections; condition after severe burns; chronic diseases accompanied by nervous and physical exhaustion, malignant diseases, chronic anemia and malnutrition, end-stage liver failure, renal failure, myxedema, collagen diseases, condition after plasma transfusion, plasmapheresis, artificial circulation.

Suxamethonium chloride should not be administered simultaneously with blood products.

Effect on the ability to drive vehicles and machinery

Within 24 hours after the use of suxamethonium chloride, patients are prohibited from driving any vehicles and engaging in other activities that require high concentration and speed of psychomotor reactions.

Drug Interactions

An increase in the duration of the neuromuscular blockade caused by suxamethonium chloride is observed with the simultaneous use of drugs that reduce the normal activity of plasma pseudocholinesterase, including organophosphorus insecticides and metrifonate, trimethaphan, neostigmine, pyridostigmine, edrophonium, cyclophosphamide, thiotepa, promazine and chlorpromazine, ketamine, morphine and its antagonists, pancuronium, propanidid. It should be borne in mind that some drugs have the potential ability to reduce the activity of plasma pseudocholinesterase: aprotinin, diphenhydramine, promethazine, estrogens, oxytocin, high-dose corticosteroids, oral hormonal contraceptives.

Drugs that increase the intensity and duration of the neuromuscular blockade caused by suxamethonium chloride through mechanisms not related to a decrease in plasma pseudocholinesterase activity: magnesium salts, lithium carbonate, quinine, chloroquine, aminoglycoside antibiotics, clindamycin and polymyxins; antiarrhythmic drugs – quinidine, procainamide, verapamil, beta-blockers, lidocaine and procaine; inhalation anesthetics – halothane, enflurane, isoflurane, diethyl ether and methoxyflurane.

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Rx Only

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.