Suxamethonium iodide (Solution) Instructions for Use

ATC Code

M03AB01 (Suxamethonium chloride)

Active Substance

Suxamethonium iodide (PhBs Pharmacopoeia of Slovakia)

Clinical-Pharmacological Group

Peripherally acting depolarizing-type muscle relaxant

Pharmacotherapeutic Group

Peripherally acting muscle relaxant

Pharmacological Action

A short-acting depolarizing muscle relaxant. It causes a blockade of neuromuscular transmission. By stimulating n-cholinergic receptors, it causes depolarization of the end plate. The process spreads to adjacent membranes, causing a generalized disorganized contraction of myofibrils (i.e., the development of blockade is preceded by muscle fasciculations – a result of a brief facilitation of neuromuscular transmission). The membranes, remaining depolarized, do not respond to additional impulses; since maintaining muscle tone requires the arrival of repeated impulses associated with repolarization of the end plate, spastic paralysis occurs.

After intravenous administration, muscle relaxation occurs in the following sequence: eyelid muscles, masticatory muscles, muscles of the fingers, eyes, limbs, neck, back and abdomen, vocal cords; then the intercostal muscles and diaphragm.

It increases cerebral blood flow and intracranial pressure under general anesthesia.

After intramuscular administration, the effect develops in 2-4 minutes; after intravenous administration – in 54-60 seconds, within 2-3 minutes muscle relaxation reaches its maximum and remains in full for 3 minutes. The duration of action is 5-10 minutes.

The severity of the action depends on the administered dose: 0.1 mg/kg – relaxation of skeletal muscles without significant effect on the respiratory muscles, 0.2-1 mg/kg – complete relaxation of the abdominal wall muscles and respiratory muscles (significant limitation or complete cessation of spontaneous breathing occurs). For prolonged muscle relaxation, repeated administration is necessary. The rapid onset of effect and subsequent rapid recovery of muscle tone allow for controlled and manageable muscle relaxation.

Pharmacokinetics

After intravenous administration, it is distributed in plasma and extracellular fluid. More than 90% is hydrolyzed by blood cholinesterase to succinic acid and choline. T_1/2 is 90 seconds at normal cholinesterase concentration. It is excreted by the kidneys. It does not cross the intact blood-brain barrier. It does not accumulate.

Indications

Interventions requiring muscle relaxation (usually short-term): switching off spontaneous breathing (endotracheal intubation, bronchoscopy); complete muscle relaxation (endoscopy, reduction of dislocations, reposition of fractures, gynecological, thoracic, abdominal surgeries); prevention of convulsions during electroconvulsive therapy; strychnine poisoning; tetanus (symptomatic therapy).

ICD codes

Dosage Regimen

Solution

Adults: IV slowly, as a bolus or by drip (for prolonged drip infusion, a 0.1% solution is used). Depending on the clinical situation with IV administration, a single dose varies from 0.1 to 1.5-2 mg/kg.

IM – 3-4 mg/kg, but not more than 150 mg. IM is used in children at doses up to 2.5 mg/kg, but not more than 150 mg, IV – 1-2 mg/kg.

For tracheal intubation – 0.2-0.8 mg/kg; for muscle relaxation and switching off spontaneous breathing – 0.2-1 mg/kg; for skeletal muscle relaxation during reduction of dislocations and reposition of bone fragments in fractures – 0.1-0.2 mg/kg; for endoscopy and EEG – 0.2 mg/kg; for prevention of complications during electroconvulsive therapy (convulsions, muscle and tendon avulsion) – 0.1-1 mg/kg IV and up to 2.5 mg/kg IM, but not more than 150 mg.

For prolonged muscle relaxation throughout the entire surgery, it can be administered fractionally, every 5-7 minutes, at 0.5-1 mg/kg. Repeated doses act for a longer duration.

Adverse Reactions

Allergic reactions: anaphylactic shock, bronchospasm.

From the cardiovascular system: decreased blood pressure, arrhythmias, bradycardia (more often in children, with repeated administration – in children and adults), conduction disturbance, cardiogenic shock.

From the sensory organs: increased intraocular pressure.

From the musculoskeletal system: myalgia (in the postoperative period); prolonged paralysis of the respiratory muscles (associated with genetically determined impairment of serum cholinesterase formation); rarely – rhabdomyolysis with the development of myoglobinemia and myoglobinuria.

Other: hyperkalemia, hypersalivation, fever.

Contraindications

Malignant hyperthermia (including in the anamnesis); myasthenia gravis; congenital and dystrophic myotonia; Duchenne muscular dystrophy; angle-closure glaucoma; acute hepatic failure; pulmonary edema; penetrating eye injuries; bronchial asthma; hyperkalemia; infancy (under 1 year); pregnancy, lactation period (breastfeeding); hypersensitivity to suxamethonium iodide.

Use in Pregnancy and Lactation

Use is contraindicated during pregnancy and lactation (breastfeeding).

Use in Hepatic Impairment

Contraindication: acute hepatic failure.

Use in Renal Impairment

Patients with renal failure (without signs of hyperkalemia and neuropathy) are administered a single dose at average doses, but it is not used for multiple administrations or in increased doses due to the risk of hyperkalemia.

Pediatric Use

Use is contraindicated in children under 1 year of age.

Use with caution in children over 1 year of age.

Special Precautions

Use with caution in emergency surgery in patients with a “full stomach”, decreased activity of serum cholinesterase (terminal stage of hepatic failure, anemia, cachexia, prolonged starvation, chronic infections, extensive burns, trauma, postpartum period, tetanus, tuberculosis, malignant neoplasms, chronic renal failure, myxedema, collagen diseases, conditions after plasma transfusion, plasmapheresis, surgeries under cardiopulmonary bypass, acute or chronic intoxication with insecticides – cholinesterase inhibitors (upon ingestion) or cholinesterase inhibitors (neostigmine methylsulfate, physostigmine, distigmine bromide, ecothiopate iodide), simultaneous use of drugs competing with suxamethonium iodide for cholinesterase (for example, procaine IV).

With an appropriate dose and repeated administration, it can also be used for longer operations, however, for prolonged muscle relaxation, non-depolarizing muscle relaxants are usually used, which are administered after preliminary tracheal intubation against the background of suxamethonium iodide.

It is used only in specialized departments with equipment for artificial lung ventilation and personnel proficient in this technique, and against the background of general anesthesia.

To prevent severe bradycardia, increased bronchial secretion and other effects associated with m-cholinomimetic action, it is recommended to administer atropine before the administration of suxamethonium iodide.

Patients with renal failure (without signs of hyperkalemia and neuropathy) are administered a single dose at average doses, but it is not used for multiple administrations or in increased doses due to the risk of hyperkalemia.

Prolonged muscle relaxation with possible apnea can be caused by several reasons: “atypical” serum cholinesterase, hereditary deficiency of serum cholinesterase or a temporary decrease in its concentration in severe liver diseases, severe anemia, after prolonged starvation, in cachexia, dehydration, febrile conditions, after acute poisonings or chronic exposure to insecticides – cholinesterase inhibitors (upon ingestion) or cholinesterase inhibitors (neostigmine methylsulfate, physostigmine, distigmine bromide), as well as with simultaneous use of drugs competing with suxamethonium iodide for cholinesterase (for example, procaine IV).

With prolonged administration at doses of 3-5 mg/kg, a so-called “dual block” may develop – a prolonged curare-like action, which can be eliminated by neostigmine methylsulfate.

Drug Interactions

It enhances the effects of cardiac glycosides.

It reduces the effectiveness of antimyasthenic drugs.

Cholinesterase inhibitors, procaine, procainamide, lidocaine, verapamil, beta-blockers, aminoglycosides, amphotericin B, clindamycin, cyclopropane, propanidid, organophosphorus insecticides, magnesium and lithium salts, quinidine, quinine, chloroquine, non-depolarizing muscle relaxants enhance and prolong the muscle relaxant action.

Halogen-containing drugs for general anesthesia enhance, while sodium thiopental and atropine reduce the undesirable effect on the cardiovascular system.

Drugs with the potential ability to reduce the activity of blood cholinesterase (aprotinin, diphenhydramine, promethazine, estrogens, oxytocin, glucocorticosteroids in high doses, oral contraceptives) enhance and prolong the muscle relaxant action of suxamethonium iodide.

It is pharmaceutically incompatible with donor blood (hydrolysis occurs), blood preservatives, serum preservatives, blood products, barbiturate solutions (precipitate forms) and alkaline solutions.

Storage Conditions

Store at 2°C (36°F) to 8°C (46°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.