Succinylcholine

Question 1

Brand Names

Answer 1

Annectine
Suxamethonium
SCh
Quelicin

Question 2

Broad category

Answer 2

Depolarizing Neuromuscular blocker

Question 3

Class

Answer 3

Depolarizer (only one in its class)

Question 4

Physical structure

Answer 4

2 ACh molecules bound together

Question 5

MOA

Answer 5

presynaptic: increase ACh release in synaptic junction

Postsynaptic: binds to both alpha subunits on nicotinic ACh receptor at motor endplate resulting in depolarization, Na+ rushes in muscle depolarizes. SCh stays bound which eventually desensitizes the receptor and becomes inactive

Question 6

Indications

Answer 6

Rapid muscle relaxation
Routine intubation
short cases
OB
RSI
Laryngospasm
Chest wall rigidity

Question 7

CV effects

Answer 7

Potential decrease in HR due to M2 stimulation
Can cause profound bradycardia or sinus arrest (esp. in peds)
may cause junctional rhythm
May cause Hyperkalemia especially in patients that are at higher risk

Question 8

Normal K+ serum increase

Answer 8

0.5 meq/L

Question 9

Other Side effects

Answer 9

Myalgias especially in large muscle groups (5mg ROC defasic or NSAIDs)

Question 10

Pressure changes

Answer 10

Increases intragastric/ LES pressure
Increased ICP (transient)
Increased IOP (peaks at 2-4 mins; gone by 6 mins)

Question 11

MH trigger?

Answer 11

YES; severe massetter spasm may be indicative

Question 12

Histamine release

Answer 12

minimal

Question 13

Absolute Contraindications

Answer 13

• MH history or Family History
• Peds (BLACK BOX WARNING D/T INCREASED RISK OF HYPERKALEMIA/RHABDO/CARDIAC ARREST WITH UNDIAGNOSED MYOPATHIES)
• Extrajunctional Receptor Upregulation (Burns, spinal cord injury, massive trauma, prolonged immobilization, guillain-barre, etc.)
• Atypical Pseudocholinesterase

Question 14

Induction dose (adults)

Answer 14

1-1.5 mg/kg

Question 15

Induction dose peds

Answer 15

1.5-2 mg/kg

Question 16

Induction dose peds IM

Answer 16

3-4 mg/kg

Question 17

Laryngospasm Dose

Answer 17

20 mg

Question 18

Onset

Answer 18

30-60 seconds

Question 19

Duration

Answer 19

5-15 mins

(Usually less than 10 mins)

Question 20

IM duration

Answer 20

10-30 mins

Question 21

Metabolism

Answer 21

Pseudocholinesterase (only 10% get to NMJ)

Question 22

Metabolites

Answer 22

Succinylmonocholine (weakly active) and Choline

Question 23

Drug to drug interactions (prolong)

Answer 23

Anticholinesterase will prolong block and may potentiate a phase II block

Question 24

What Factors decrease Pseudocholinesterase and thus prolong block

Answer 24

• severe liver disease
• advanced age
• pregnancy
  -malnutrition
• anticholinesterase drugs
• Reglan
• Oral contraceptives