suxamethonium chloride at a glance
Medicine class
Depolarising neuromuscular blocker.
Licensed use
Muscle relaxation during general anaesthesia.
Administration
Given into a vein by or under the close supervision of an experienced anaesthetist.
Important point
It paralyses breathing muscles without causing unconsciousness, so anaesthesia and assisted ventilation are essential.
What is suxamethonium chloride used for?
The selected UK product is licensed for muscle relaxation during general anaesthesia.
It may facilitate procedures such as inserting a breathing tube when rapid, brief muscle paralysis is required.
How does suxamethonium chloride work?
Suxamethonium acts like acetylcholine at receptors where motor nerves meet skeletal muscle. It persistently depolarises the muscle endplate, briefly causing visible muscle twitching before producing flaccid paralysis. Plasma cholinesterase normally breaks it down rapidly, allowing muscle function to return.
suxamethonium chloride preparations and strengths
Injection
Route: Parenteral
Strengths: 50 mg/mL
How to take suxamethonium chloride
This is not self-administered. It is given into a vein by injection or infusion under controlled anaesthetic conditions, with equipment and trained staff available to maintain the airway and breathing. Follow the hospital's instructions for preparing for and recovering from general anaesthesia.
Tell the anaesthetist about previous reactions to anaesthetics or muscle relaxants.
Mention any family history of malignant hyperthermia or unusually prolonged paralysis after an anaesthetic.
Provide a complete list of medicines and disclose recent pesticide exposure or blood transfusion.
suxamethonium chloride side effects
Common or expected effects
- Muscle twitching followed by muscle aches after the operation
- Slower or faster heart rate
- Skin flushing or rash
- Temporary rise in blood potassium
- Raised pressure inside the eye
- Abdominal discomfort or a feeling of fullness
Get urgent medical advice
- Severe allergic reaction, with breathing difficulty, swelling, rash, faintness or collapse
- Prolonged paralysis, weak breathing or inability to breathe independently
- Dangerous heart-rhythm disturbance or cardiac arrest
- Malignant hyperthermia, with a rapidly rising temperature and muscle rigidity
- Significant muscle breakdown, which may cause weakness, tenderness and dark urine
suxamethonium chloride in pregnancy
Suxamethonium chloride may be used during pregnancy when the anaesthetic team considers it necessary. Only small amounts cross the placenta, but reduced plasma cholinesterase activity during pregnancy and shortly after birth can mildly prolong paralysis, so specialist anaesthetic assessment and monitoring are important.
suxamethonium chloride while breastfeeding
It is unknown whether suxamethonium passes into breast milk, but effects in a breastfed infant are not anticipated because it is rapidly broken down. Breastfeeding can generally resume after anaesthesia once the parent is awake, stable and able to hold and feed the baby safely; discuss the complete anaesthetic and postoperative medicine plan with the clinical team.
suxamethonium chloride interactions
The anaesthetist needs a complete medicine and exposure history because several agents alter the intensity, duration or risks of suxamethonium.
Aminoglycosides and certain other antibiotics
Medicines including neomycin, vancomycin, clindamycin and polymyxins may enhance neuromuscular blockade.
Anticholinesterases
Neostigmine, pyridostigmine, donepezil and related medicines can intensify or prolong the depolarising block.
ACE inhibitors and other potassium-raising medicines
Concurrent use may increase the risk of hyperkalaemia.
Common questions about suxamethonium chloride
Answers are fully visible for fast scanning and source review.
Why is suxamethonium chloride used during an anaesthetic?
It produces rapid, brief skeletal-muscle paralysis, which can help the anaesthetist manage the airway and provide suitable muscle relaxation during general anaesthesia.
Does suxamethonium chloride make you unconscious?
No. It causes paralysis but does not cause unconsciousness or pain relief, so it must only be used with adequate anaesthesia.
Why is breathing support needed after suxamethonium chloride?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.