Suxamethonium

Question 1

Suxamethonium - Type

Answer 1

Depolarising muscle relaxant

Question 2

Suxamethonium - Presentation

Answer 2

100mg in 2ml

Question 3

Suxamethonium - Action

Answer 3

Acts like the neurotransmitter acetylcholine at the neuromuscular junction.

Persists for a period long enough to exhaust the motor endplate by prolonged depolarisation

Onset approx. 45 sec, duration 5-7 min

Question 4

Suxamethonium - Use

Answer 4

To facilitate airway management in selected pts

Question 5

Suxamethonium - Adverse effects (5)

Answer 5

1. Bradycardia
2. Potassium release
3. Increased intraocular and intragastric pressure
4. Occasionally, prolonged paralysis
5. Has been associated with malignant hyperthermia

Question 6

Suxamethonium - Contraindications (3)

Answer 6

1. Previous reaction to suxamethonium
2. Suspected hyperkalaemia
3. Use in children

Question 7

Suxamethonium - Precautions (5)

Answer 7

1. Elderly pt
2. Neuromuscular disease
3. Hypothermic pt
4. Fitting pt
5. Pt with reversible pathology

Select pts carefully, always have a fallback position

Question 8

Suxamethonium - Dose

Answer 8

Adult - 1.5mg/kg IV over 30-60 sec to max 150mg

Question 9

Suxamethonium - Special notes

Answer 9

If HR <50 consider atropine prior to suxamethonium
May cause bradycardia, consider atropine
NB Bradycardia may be a result of a head injury and raised ICP, thus BP will be elevated. In this case there is no requirement for atropine regardless of the degree of bradycardia.
Prior to admin give IV ketamine 1mg/kg over 30-60 sec
Follow up with additional ketamine 1mg/kg doses IV at 1-5 minute intervals post intubation.