Succinylcholine

Question 1

Succinylcholine Class

Answer 1

Depolarizing muscle blocking agent

Question 2

Succinylcholine Uses (3)

Answer 2

Rapid sequence induction

Laryngospasm

ECT

Question 3

Succinylcholine Dosing

Answer 3

Induction dosing: 1 mg/kg

IM induction: 4 mg/kg

Laryngospasm: 40 mg

Question 4

Succinylcholine Onset and DOA

Answer 4

Onset: 60 seconds
DOA: 15 minutes

Question 5

Succinylcholine Redistribution

Answer 5

Diffusion away from the neuromuscular junction into the ECF

Question 6

Succinylcholine Metabolism

Answer 6

Plasma cholinesterases, aka pseudocholinesterases or butyrocholinesterase

Plasma choliesterases are made by the liver

Metabolism is prolonged in patients with plasma cholinesterase deficiency

Question 7

Succinylcholine Excretion

Answer 7

Eliminated by the kidneys

Question 8

Succinylcholine CV Effects

Answer 8

Bradycardia due to direct stimulation of muscarinic receptors of the SA node

Question 9

Succinylcholine Electrolyte Risks

Answer 9

Hyperkalemia risk: plasma K+ concentration may increase by 0.5 mEq/liter in normal patients and 5–10 mEq/liter in burn, trauma, or head-injury patients

Question 10

Cause of Succinylcholine Hyperkalemia

Answer 10

proliferation of extrajunctional postsynaptic cholinergic nicotinic receptors

Question 11

Conditions that can Cause Hyperkalemia with Succinylcholine Administrations

Answer 11

Thermal injury (burns)

Paraplegia or hemiplegia

Skeletal muscle trauma

Upper motor neuron injury (head injury, cerebrovascular accident, Parkinson’s disease)

Question 12

Succinylcholine Increased Pressures

Answer 12

Increase in ICP: mitigate with defasciculating dose of non depolarizer

Intraocular pressure (IOP): short duration (6 min), do not administer with open globe injury

Gastric pressure: prevent with defasciculating dose of non depolarizer

Question 13

Succinylcholine Muscular Effects

Answer 13

Fasciculations/post op muscle pain (myalgias)

Rhabdomyolysis leading to hyperkalemia and cardiac arrest

Question 14

Succinylcholine Early Sign of MH

Answer 14

Masseter spasm early sign of MH

Question 15

Succinylcholine Potential Contraindications

Answer 15

Pre-existing Hyperkalemia

Conditions that increase proliferation of extrajunctional postsynaptic cholinergic nicotinic receptors

Severe Sepsis

Duchenne Muscular Dystrophy

Peds under 8

Question 16

Drugs that Increase Succinylcholine DOA (8)

Answer 16

Antibiotics (neomycin, streptomycin, dihydrostreptomycin, kanamycin, gentamicin, polymyxin A, polymyxin B, colistin, lincomycin)

Amide local anesthetics

Anticholinesterase agents

Hyperkalemia

Hypermagnesemia

Lithium

Calcium channel blockers

Inherited pseudocholinesterase defect (atypical pseudocholinesterase)

Question 17

Test to Assess Pseudocholinesterase Defect

Answer 17

Dibucaine test:
Local anesthetic that inhibits normal pseudocholinesterase by ~ 80%, but abnormal pseudocholinesterase types will be less inhibited

% inhibited = Dibucaine #

Question 18

Heterozygous Pseudocholinesterase Defect

Answer 18

50-60% pseudocholinesterase inhibited

Prolonged by 1-2x

Question 19

Homozygous Pseudocholinesterase Defect

Answer 19

20% pseudocholinesterase inhibited

Prolonged by up to 8 hrs

Question 20

Other names for Plasma Cholinesterases

Answer 20

Pseudocholinesterases or butyrocholinesterase