Suxamethonium intravenous for adults

Who can administer

Administration restricted- see Appendix 1

Important information

  • Suxamethonium should be administered only by or under close supervision of an experienced clinician (anaesthetist, intensivist, emergency physician)
  • It is given intravenously after anaesthesia has been induced and should not be administered to the conscious patient
  • Anaphylactic reactions have been documented as has cross-reactivity with other neuromuscular blocking agents

Available preparations

Murexal 100mg/10mL solution for injection in pre-filled syringe

Suxamethonium 100mg per 2ml ampoule 

Reconstitution

Pre-filled syringe

  • Already in solution

Ampoules

  • Draw up using a 5micron filter needle

Infusion fluids

Glucose 5% or Sodium chloride 0.9%

Methods of intravenous administration

Bolus intravenous injection (pre-filled syringe is preferable)

  • The medicinal product should not be used if the tamper evident seal on the syringe is broken.
  • The external surface of the syringe is sterile until the blister is opened. The blister must not be opened until use
  • When handled using an aseptic method, this medicinal product can be placed on a sterile field once it has been removed from the blister
  • Administer required dose as a bolus intravenous injection

Continuous intravenous infusion (ampoules only)

  • Dilute to a concentration of either 1mg/ml or 2mg/ml (i.e. one ampoule of 100mg in 50 or 100ml infusion fluid)

Dose in adults

Usual dose to achieve endotracheal intubation 

  • Give 1 mg/kg body weight as a single dose 
  • This dose will usually produce muscular relaxation in about 30 to 60 seconds and has a duration of action of about 2 to 6 minutes
  • Larger doses will produce more prolonged muscular relaxation, but doubling the dose does not necessarily double the duration of relaxation
  • See also Further information
  • Supplementary doses of 50 to 100% of the initial dose may be administered for the maintenance of muscle relaxation during short surgical or other procedures performed under general anaesthesia, at intervals of 5-10 minutes as required 
  • During administration by repeated bolus injections: total dose should not exceed 500mg

Intravenous infusion (ampoules only)

  • Give at a rate of 2.5 to 4mg per minute
  • The infusion rate thereafter should be adjusted according to response

Elderly

  • Dose requirements of suxamethonium in elderly are comparable to those for adults.

Renal impairment

  • A single dose of suxamethonium may be administered to patients with renal insufficiency in the absence of hyperkalaemia
  • Multiple or larger doses may cause clinically significant rises in serum potassium and should not be used.

Hepatic impairment

  • No dose adjustment is required in patients with hepatic impairment  
  • Although plasma cholinesterase levels often fall in patients with liver disease, levels are seldom low enough to significantly prolong suxamethonium-induced apnoea

Further information

  • The use of small doses of non-depolarising muscle relaxants given minutes before suxamethonium administration has been advocated for the reduction of incidence and severity of suxamethonium-associated muscle pains.
  • This technique may require the use of doses of suxamethonium chloride in excess of 1 mg/kg to achieve satisfactory conditions for endotracheal intubation 

Storage

Murexal syringe

  • Store in a refrigerator (2-80C)
  • Do not freeze
  • Keep the pre-filled syringe in its unopened blister until use
  • Once removed from the refrigerator, the syringe may be stored at room temperature (not exceeding 250C)- for up to 30 days (however, it must be kept it its unopened blister)
  • Once taken out of the refrigerator- the syringe packaging must be marked with the date of removal from the fridge

Suxamethonium ampoules

  • Store in a refrigerator (2 - 80C)
  • Do not freeze

References

SPC: 09/01/2020

SPC Murexal 24/04/2020

Therapeutic classification

Ultra-short acting depolarising, neuromuscular blocking agent