Suxamethonium Ethypharm
Suxamethonium chloride dihydrate 50 mg/ml – Solution for injection/infusion
Quick Facts: Suxamethonium Ethypharm
Key Takeaways
- Ultra-rapid onset: Suxamethonium works within 30-60 seconds, making it the fastest neuromuscular blocker for emergency intubation
- Short duration: Muscle relaxation lasts only 2-6 minutes, allowing rapid recovery of spontaneous breathing
- Hospital use only: This medicine is exclusively administered by experienced anesthesiologists with ventilation equipment available
- Malignant hyperthermia risk: Patients with personal or family history must not receive this drug due to potentially fatal hyperthermia
- Strict contraindications: Must not be used in Duchenne muscular dystrophy, hyperkalemia, or pseudocholinesterase deficiency
What Is Suxamethonium Ethypharm and What Is It Used For?
Suxamethonium Ethypharm contains suxamethonium chloride (also known as succinylcholine), a depolarizing neuromuscular blocking agent that produces rapid, short-duration muscle relaxation during general anesthesia in adults and children. It is the gold standard for rapid sequence intubation (RSI) in emergency airway management.
Suxamethonium belongs to a class of medicines known as depolarizing neuromuscular blocking agents. These drugs work by mimicking the action of acetylcholine — the natural neurotransmitter at the neuromuscular junction — causing initial brief muscle contractions (fasciculations) followed by a sustained state of muscle paralysis. This mechanism distinguishes suxamethonium from non-depolarizing agents such as rocuronium or vecuronium, which block the acetylcholine receptor without initial stimulation.
The primary clinical use of suxamethonium is to facilitate endotracheal intubation during rapid sequence induction of anesthesia. This is a procedure used when the patient requires emergency airway management and there is a risk of aspiration of stomach contents into the lungs. Suxamethonium is ideal for this purpose because it has the fastest onset of any neuromuscular blocking agent (30-60 seconds) and an ultra-short duration of action (2-6 minutes), which means that if intubation fails, the patient will regain the ability to breathe spontaneously within minutes.
Suxamethonium is also used for short surgical procedures that require brief periods of muscle relaxation, such as repositioning dislocated joints or electroconvulsive therapy (ECT). In emergency medicine, it remains a cornerstone of airway management protocols worldwide, endorsed by organizations including the Difficult Airway Society, the American Society of Anesthesiologists (ASA), and the European Society of Anaesthesiology and Intensive Care (ESAIC).
Suxamethonium is metabolized rapidly by plasma cholinesterase (also called pseudocholinesterase or butyrylcholinesterase), an enzyme found in the blood. This rapid metabolism accounts for its ultra-short duration of action. However, in patients with inherited or acquired deficiency of this enzyme, the drug's effects may be significantly prolonged.
Suxamethonium Ethypharm is a hospital-only medication. It will always be administered by a specialist anesthesiologist in a controlled environment with full resuscitation and ventilation equipment available. You will not be expected to manage this medication yourself.
What Should You Know Before Receiving Suxamethonium Ethypharm?
Before receiving suxamethonium, your anesthesiologist must be informed about your full medical history, especially any family history of malignant hyperthermia, muscle diseases, or unusual reactions to anesthesia. Several serious contraindications exist that absolutely prevent the use of this drug.
Contraindications
You must not receive Suxamethonium Ethypharm if:
- You are allergic to suxamethonium chloride dihydrate or any of the other ingredients in this medicine
- You have been told by a doctor that you have abnormal cholinesterase activity (cholinesterase is an enzyme that breaks down the drug — if it does not work properly, the drug's effects can last dangerously long)
- You or anyone in your family has ever experienced malignant hyperthermia (a rare but potentially fatal condition causing extremely high body temperature during anesthesia)
- You have abnormally high levels of potassium in your blood (hyperkalemia)
- You or anyone in your family has a condition causing muscle weakness such as myotonia congenita or dystrophia myotonica
- You have Duchenne muscular dystrophy or another form of muscular dystrophy causing progressive muscle weakness and loss of muscle tissue
Malignant hyperthermia is a rare, inherited condition triggered by certain anesthetic agents including suxamethonium. It causes a rapid, uncontrolled rise in body temperature, muscle rigidity, and metabolic crisis that can be fatal if not treated immediately with dantrolene. If you have any family history of unusual reactions to anesthesia, unexplained deaths during surgery, or high fevers during anesthesia, you must inform your anesthesiologist immediately.
Warnings and Precautions
Your anesthesiologist will exercise particular caution if you have any of the following conditions. Tell the medical team before your procedure if you:
- Have an infection that causes muscle stiffness (tetanus) or tuberculosis
- Feel generally unwell, have a fever, or have cancer
- Have a blood disorder called anemia or suffer from malnutrition
- Have serious problems with your liver or kidneys
- Have an autoimmune disease, such as a thyroid condition (myxedema)
- Have a connective tissue disease causing joint problems
- Have heart problems (including previous heart attack, heart disease, or irregular heartbeat)
- Have had or are currently having plasma exchange therapy (plasmapheresis)
- Have had any form of head injury or are recovering from major trauma or severe burns
- Have a spinal cord injury, nerve damage, or muscle wasting
- Have a muscle disease such as myasthenia gravis
- Have recently injured your eye or have glaucoma (increased eye pressure)
- Have ever had an allergic reaction to any muscle relaxant given during an operation
- Have been immobile for a long period
- Have blood poisoning (sepsis)
Suxamethonium causes a transient rise in intraocular pressure, which is why it must be used with extreme caution in patients with open eye injuries or glaucoma. It also causes a temporary increase in intragastric pressure, though this is generally offset by the simultaneous increase in lower esophageal sphincter tone. The drug can cause a transient rise in serum potassium levels of approximately 0.5 mmol/L in healthy individuals, but this rise can be massive and life-threatening in patients with burns, denervation injuries, prolonged immobilization, or undiagnosed myopathies.
Allergic Reactions
Serious allergic reactions (anaphylaxis) can occur, even if you have never previously received a neuromuscular blocking agent. Suxamethonium is one of the most common causes of anaphylaxis during anesthesia. Symptoms typically manifest as skin flushing or rash (either over the entire body or at the injection site), and may be followed by breathing difficulties, swelling, dizziness, rapid heart rate, sweating, and loss of consciousness. At the first sign of an allergic reaction, your anesthesiologist will stop the infusion immediately and initiate emergency treatment.
Pregnancy and Breastfeeding
If you are pregnant, breastfeeding, think you may be pregnant, or are planning to have a baby, tell your doctor before receiving this medicine. Suxamethonium crosses the placenta in small amounts. While there is limited data on its use in pregnancy, it has been used historically for rapid sequence intubation in pregnant patients requiring emergency cesarean section under general anesthesia. The decision to use suxamethonium during pregnancy will be made by your anesthesiologist based on the individual clinical situation. There is no specific information regarding the excretion of suxamethonium in breast milk, but given its ultra-short duration of action and rapid metabolism, significant exposure of the infant is considered unlikely.
Use in Children
Extra caution and monitoring are required when suxamethonium is administered to infants and children. In many countries and hospital guidelines, the routine use of suxamethonium in children has been largely replaced by rocuronium due to rare reports of cardiac arrest from hyperkalemia in children with undiagnosed muscular dystrophies. However, suxamethonium remains available and is used in emergency situations when no alternative is suitable, such as laryngospasm or emergency intubation when intravenous access is not available (in which case intramuscular administration may be used).
How Does Suxamethonium Ethypharm Interact with Other Drugs?
Suxamethonium has significant interactions with many drugs. Some medications can prolong or enhance its neuromuscular blocking effect, while others can increase the risk of serious adverse effects such as hyperkalemia or cardiac arrhythmias. Your anesthesiologist will review all your current medications before administration.
Tell your doctor, nurse, or appropriate hospital staff if you are taking, have recently taken, or might take any other medicines. The following list covers the most clinically important drug interactions. Many of these interactions relate to the inhibition of plasma cholinesterase, the enzyme responsible for metabolizing suxamethonium, or to additive effects on the neuromuscular junction or cardiovascular system.
Major Interactions
| Drug / Drug Class | Effect of Interaction | Clinical Significance |
|---|---|---|
| Anticholinesterases (neostigmine, donepezil, echothiopate) | Inhibit plasma cholinesterase, prolonging suxamethonium block | May cause prolonged paralysis and respiratory depression |
| Cyclophosphamide, thiotepa (cytotoxic agents) | Reduce plasma cholinesterase levels | Significantly prolonged duration of neuromuscular block |
| MAO inhibitors (phenelzine) | Inhibit plasma cholinesterase | Unpredictably prolonged paralysis |
| Bambuterol | Potent cholinesterase inhibitor | Can prolong block by several hours |
| Cardiac glycosides (digoxin) | Suxamethonium-induced hyperkalemia may potentiate digitalis toxicity | Risk of fatal cardiac arrhythmias |
Other Important Interactions
| Drug / Drug Class | Effect of Interaction | Clinical Significance |
|---|---|---|
| Local anesthetics (lidocaine, procaine) | Enhance neuromuscular block; reduce cholinesterase activity | Prolonged paralysis |
| Antibacterials (neomycin, vancomycin, polymyxin B) | Additive neuromuscular blocking effect | Prolonged block possible |
| General anesthetics (propofol, volatile agents) | Enhance neuromuscular block | Reduced dose of suxamethonium may be needed |
| Benzodiazepines (diazepam, midazolam) | May reduce intensity of fasciculations | Generally beneficial; no dose adjustment needed |
| Calcium channel blockers (nifedipine, verapamil) | May enhance neuromuscular block | Monitor recovery closely |
| Magnesium salts | Enhance neuromuscular block | Important in eclampsia patients receiving magnesium |
| Antiepileptics (carbamazepine, phenytoin) | May cause resistance to non-depolarizing agents but can prolong suxamethonium block | Monitor for prolonged effect |
| Antimalarials (quinine, chloroquine) | Reduce cholinesterase activity | Prolonged paralysis |
| Metoclopramide | Inhibits plasma cholinesterase | Prolonged block possible |
You should also tell your anesthesiologist if you have been recently exposed to organophosphate insecticides (such as sheep dip chemicals), as these irreversibly inhibit cholinesterase and can cause dangerously prolonged paralysis. Similarly, recent blood transfusions may affect cholinesterase levels and should be disclosed.
Suxamethonium Ethypharm must not be mixed with other medicines except those specifically mentioned in the dilution instructions. It is an acidic solution and must not be mixed with strongly alkaline solutions such as barbiturates (e.g., thiopental), as this can cause precipitation and loss of efficacy.
What Is the Correct Dosage of Suxamethonium Ethypharm?
The dose of suxamethonium depends on body weight, the degree of muscle relaxation required, the route of administration, and the individual patient's response. Standard intravenous dose for adults is 1 mg/kg. The maximum total dose should not exceed 500 mg. This medicine is always administered by an anesthesiologist in a hospital.
Suxamethonium Ethypharm is given as an injection into a vein (intravenously) or as a continuous intravenous infusion. Your anesthesiologist will determine the appropriate dose based on your weight, the type of procedure, and your expected response to the drug. Ventilatory support equipment will always be available when this medicine is administered.
Adults, Elderly, and Adolescents Over 12 Years
Intravenous Injection (Bolus)
The standard dose for endotracheal intubation is 1 mg per kg body weight. This dose typically produces muscle relaxation within approximately 30 to 60 seconds with a duration of action of approximately 2 to 6 minutes. Larger doses will prolong the duration of block, but doubling the dose does not necessarily double the duration of relaxation.
Supplemental doses: Additional doses of 50% to 100% of the initial dose may be given at 5 to 10-minute intervals to maintain muscle relaxation during short surgical procedures.
Intravenous Infusion (Continuous)
Suxamethonium may be given as a continuous intravenous infusion as a 0.1% to 0.2% solution, diluted with 5% glucose solution or sterile isotonic saline, at a rate of 2.5 to 4 mg per minute. The infusion rate should be adjusted according to the individual patient's response.
Maximum total dose: 500 mg.
Children
Infants and younger children are more resistant to the effects of suxamethonium compared to adults, requiring higher doses per kilogram of body weight.
| Age Group | Route | Dose | Notes |
|---|---|---|---|
| Children 1–12 years | Intravenous injection | 1–2 mg/kg | Higher dose range often required |
| Infants under 1 year | Intravenous injection | 2 mg/kg | Most resistant age group |
Elderly Patients
The dose for elderly patients is the same as for adults. However, elderly patients may be more susceptible to cardiac arrhythmias, particularly if they are taking digitalis-type medications (such as digoxin). Careful cardiac monitoring is essential in this population, and the anesthesiologist may opt for an alternative agent if significant cardiac risk factors are present.
Overdose
Since suxamethonium is administered in a hospital setting under careful medical supervision, overdose is unlikely. If an overdose does occur, the primary manifestation is prolonged neuromuscular paralysis with respiratory depression. Management consists of maintaining ventilatory support (mechanical ventilation) until the drug is metabolized and spontaneous breathing returns.
The use of neostigmine and other anticholinesterase agents should generally be avoided, as these drugs prolong the depolarizing effect of suxamethonium. However, if a Phase II block develops (which can occur after repeated or prolonged use), reversal with neostigmine may be considered by the anesthesiologist, guided by neuromuscular monitoring (train-of-four stimulation). When neostigmine is used, it must be given together with an anticholinergic agent such as atropine.
What Are the Side Effects of Suxamethonium Ethypharm?
Like all medicines, suxamethonium can cause side effects, although not everyone experiences them. The most common side effects are post-operative muscle pain (myalgia), fasciculations, and gastrointestinal discomfort. Rare but serious side effects include malignant hyperthermia, severe hyperkalemia, cardiac arrhythmias, and anaphylaxis.
If you experience any side effects after your operation, tell your doctor, nurse, or hospital staff. This includes any effects not listed below. Serious allergic reactions (anaphylaxis) to suxamethonium are rare but can occur, even in patients who have never previously received a neuromuscular blocking agent. Seek immediate medical attention if you notice any signs of a severe allergic reaction such as difficulty breathing, wheezing, swelling of the face, lips, tongue, or throat, skin rash, hives, itching, or feeling faint.
Very Common
May affect more than 1 in 10 people
- Abdominal cramps, pain, feeling of nausea or bloating
- Visible muscle twitching (fasciculations) under the skin
- Post-operative muscle pain (myalgia) — your doctor will monitor you for this
Common
May affect up to 1 in 10 people
- Anaphylactic reactions with breathing difficulties, swelling, dizziness, rapid heart rate, sweating, and loss of consciousness
- Increased fluid pressure in the eye, which may cause headache or blurred vision
- Skin flushing and skin rash
- Elevated potassium levels in the blood (hyperkalemia)
- Fast or slow heart rate (tachycardia or bradycardia)
- Rhabdomyolysis (muscle breakdown releasing proteins into the blood) — may cause dark, red- or cola-colored urine, muscle pain, stiffness, and weakness
Rare
May affect up to 1 in 1,000 people
- Abnormal heart rhythm (arrhythmia)
- Cardiac problems, changes in heartbeat pattern, or cardiac arrest
- Difficulty breathing or temporary shortness of breath (bronchospasm)
- Difficulty opening the mouth (trismus / masseter muscle rigidity)
Very Rare
May affect up to 1 in 10,000 people
- Malignant hyperthermia — a life-threatening condition with dangerously elevated body temperature, treated with dantrolene
Not Known
Frequency cannot be estimated from available data
- Excessive saliva production (hypersalivation)
- High or low blood pressure
Contact your doctor or nurse immediately if you experience: difficulty breathing, wheezing, or breathing problems; swelling of eyelids, face, lips, tongue, or other body parts; rash, itching, or hives on the skin; feeling faint; dark or cola-colored urine with muscle pain or weakness.
How Should Suxamethonium Ethypharm Be Stored?
Suxamethonium Ethypharm must be stored in a refrigerator between 2°C and 8°C. It must not be frozen. The solution should be kept in its original packaging to protect from light and used immediately after opening.
This medicine will be stored and handled by the pharmacy and anesthesia departments in your hospital. However, the following storage requirements apply:
- Temperature: Store in a refrigerator at 2°C to 8°C. Do not freeze.
- Light protection: Keep in the original packaging to protect from light, as the solution is light-sensitive.
- Single use: This medicine should be used immediately after opening. Any remaining solution must be discarded.
- Visual inspection: Do not use if the solution is discolored or contains visible particles.
- Expiry date: Do not use after the expiry date shown on the carton and ampoule after "EXP." The expiry date refers to the last day of that month.
- Disposal: Unused medicine should be disposed of in accordance with local hospital protocols to protect the environment. It should not be disposed of via wastewater or household waste.
The requirement for refrigeration is important because suxamethonium degrades at room temperature, losing potency over time. The degradation products include succinylmonocholine and choline, which have reduced neuromuscular blocking activity. Hospital pharmacies typically have strict protocols for monitoring the cold chain to ensure the drug remains effective.
Keep this medicine out of the sight and reach of children, although as a hospital-only medicine, this is managed by hospital staff.
What Does Suxamethonium Ethypharm Contain?
Each 2 ml ampoule contains 100 mg of suxamethonium chloride dihydrate (equivalent to 73.1 mg suxamethonium) as the active substance, with hydrochloric acid for pH adjustment and water for injections as excipients.
Active Substance
The active substance is suxamethonium chloride dihydrate at a concentration of 50 mg/ml. Each 2 ml clear glass ampoule therefore contains 100 mg of suxamethonium chloride dihydrate, which is equivalent to 73.1 mg of suxamethonium base. Suxamethonium (also known internationally as succinylcholine) is a synthetic diacetylcholine ester — essentially two molecules of acetylcholine joined together — which explains its pharmacological activity at the neuromuscular junction.
Other Ingredients (Excipients)
- Hydrochloric acid — used for pH adjustment to maintain the acidic pH necessary for stability
- Water for injections — the solvent base
Appearance and Packaging
Suxamethonium Ethypharm solution for injection/infusion is a clear, colorless solution supplied in clear glass ampoules. Each 2 ml ampoule contains 100 mg of suxamethonium chloride dihydrate. The product is packaged in cartons of 10 ampoules.
Marketing Authorization Holder
Ethypharm, 194 Bureaux de la Colline, Bâtiment D, 92213 Saint-Cloud CEDEX, France.
This medicine is authorized across the European Economic Area under various names including Suxamethonium Chloride Ethypharm (Belgium, Ireland, Netherlands, United Kingdom), Suxamethonium chloride dihydrate Ethypharm (Denmark, Norway), and Suxametonio Ethypharm (Spain).
Dilution Instructions (For Healthcare Professionals)
For continuous intravenous infusion, suxamethonium may be diluted to a 0.1% to 0.2% solution using 5% glucose solution (50 mg/ml glucose) or sterile isotonic saline solution. The infusion rate should be adjusted to 2.5 to 4 mg per minute according to the patient's response. The product is for single use only; any unused solution should be discarded.
Frequently Asked Questions About Suxamethonium Ethypharm
Suxamethonium (succinylcholine) is a depolarizing neuromuscular blocking agent used to produce rapid, short-duration muscle relaxation during general anesthesia. Its primary use is in rapid sequence intubation (RSI) for emergency airway management — a procedure where a breathing tube is placed quickly into the trachea to secure the airway. It is also used for short surgical procedures requiring brief muscle relaxation, such as electroconvulsive therapy (ECT) and repositioning of dislocated joints. With an onset of just 30-60 seconds, it is the fastest-acting neuromuscular blocker available.
The most dangerous side effects include malignant hyperthermia (a rare but life-threatening condition causing extreme body temperature rise), severe hyperkalemia (dangerously high potassium levels that can cause cardiac arrest, particularly in patients with burns, spinal cord injuries, or undiagnosed myopathies), anaphylaxis (severe allergic reaction), and cardiac arrhythmias including bradycardia and cardiac arrest. Prolonged paralysis can also occur in patients with pseudocholinesterase deficiency. All of these are managed by the anesthesiology team in a hospital setting.
Suxamethonium is absolutely contraindicated in patients with: known hypersensitivity to suxamethonium; abnormal plasma cholinesterase activity; personal or family history of malignant hyperthermia; hyperkalemia (high blood potassium); and neuromuscular disorders such as Duchenne muscular dystrophy, myotonia congenita, or dystrophia myotonica. It should also be used with extreme caution (or avoided) in patients with major burns, severe trauma, spinal cord injuries, or prolonged immobilization after the first 24 hours due to the risk of massive potassium release.
Suxamethonium has the fastest onset of any neuromuscular blocking agent. When given intravenously at the standard dose of 1 mg/kg, complete muscle relaxation suitable for intubation occurs within 30 to 60 seconds. The effect then lasts approximately 2 to 6 minutes, after which the drug is metabolized by plasma cholinesterase and spontaneous breathing returns. This ultra-rapid onset and short duration make it ideal for rapid sequence intubation in emergency situations.
Yes, suxamethonium can be given to children, though with extra caution and monitoring. Children aged 1-12 years typically require 1-2 mg/kg intravenously, while infants under 1 year need 2 mg/kg because they are more resistant to the drug. In many countries, routine use in children has been largely replaced by rocuronium due to rare reports of cardiac arrest from hyperkalemia in children with undiagnosed muscular dystrophies. However, suxamethonium remains available for emergency situations such as laryngospasm.
Suxamethonium Ethypharm must be stored in a refrigerator at 2-8°C and must not be frozen. It should be kept in its original packaging to protect from light, as it is light-sensitive. The solution must be used immediately after opening the ampoule, and any remaining solution must be discarded. Suxamethonium degrades at room temperature, so maintaining the cold chain is critical for ensuring the drug remains effective.
References
- European Medicines Agency (EMA). Suxamethonium Chloride – Summary of Product Characteristics. Available at: www.ema.europa.eu
- British National Formulary (BNF). Suxamethonium Chloride. National Institute for Health and Care Excellence. Available at: bnf.nice.org.uk
- Martyn JAJ, Richtsfeld M. Succinylcholine-induced hyperkalemia in acquired pathologic states: etiologic factors and molecular mechanisms. Anesthesiology. 2006;104(1):158-169. doi:10.1097/00000542-200601000-00022
- Difficult Airway Society (DAS). Guidelines for management of unanticipated difficult intubation in adults. British Journal of Anaesthesia. 2015;115(6):827-848.
- World Health Organization (WHO). Model List of Essential Medicines, 23rd List (2023). Geneva: WHO; 2023.
- Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: a review. Orphanet Journal of Rare Diseases. 2015;10:93. doi:10.1186/s13023-015-0310-1
- Naguib M, Lien CA. Pharmacology of muscle relaxants and their antagonists. In: Miller RD, ed. Miller's Anesthesia. 9th ed. Philadelphia: Elsevier; 2020:832-882.
- European Society of Anaesthesiology and Intensive Care (ESAIC). Neuromuscular blockade guidelines. European Journal of Anaesthesiology. 2023;40(5):313-339.
- U.S. Food and Drug Administration (FDA). Anectine (Succinylcholine Chloride) Prescribing Information. Available at: www.fda.gov
- Appropriate use of neuromuscular blocking drugs. In: WHO Model Formulary 2008. Geneva: World Health Organization; 2008.
About the Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, comprising licensed physicians specializing in anesthesiology, pharmacology, and critical care medicine. Our team follows the GRADE evidence framework and bases all recommendations on peer-reviewed research and international guidelines from WHO, EMA, BNF, and FDA.
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