Succinylcholine Flashcards
Succinylcholine Class
Depolarizing muscle blocking agent
Succinylcholine Uses (3)
Rapid sequence induction
Laryngospasm
ECT
Succinylcholine Dosing
Induction dosing: 1 mg/kg
IM induction: 4 mg/kg
Laryngospasm: 40 mg
Succinylcholine Onset and DOA
Onset: 60 seconds
DOA: 15 minutes
Succinylcholine Redistribution
Diffusion away from the neuromuscular junction into the ECF
Succinylcholine Metabolism
Plasma cholinesterases, aka pseudocholinesterases or butyrocholinesterase
Plasma choliesterases are made by the liver
Metabolism is prolonged in patients with plasma cholinesterase deficiency
Succinylcholine Excretion
Eliminated by the kidneys
Succinylcholine CV Effects
Bradycardia due to direct stimulation of muscarinic receptors of the SA node
Succinylcholine Electrolyte Risks
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
Cause of Succinylcholine Hyperkalemia
proliferation of extrajunctional postsynaptic cholinergic nicotinic receptors
Conditions that can Cause Hyperkalemia with Succinylcholine Administrations
Thermal injury (burns)
Paraplegia or hemiplegia
Skeletal muscle trauma
Upper motor neuron injury (head injury, cerebrovascular accident, Parkinson’s disease)
Succinylcholine Increased Pressures
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
Succinylcholine Muscular Effects
Fasciculations/post op muscle pain (myalgias)
Rhabdomyolysis leading to hyperkalemia and cardiac arrest
Succinylcholine Early Sign of MH
Masseter spasm early sign of MH
Succinylcholine Potential Contraindications
Pre-existing Hyperkalemia
Conditions that increase proliferation of extrajunctional postsynaptic cholinergic nicotinic receptors
Severe Sepsis
Duchenne Muscular Dystrophy
Peds under 8
Drugs that Increase Succinylcholine DOA (8)
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)
Test to Assess Pseudocholinesterase Defect
Dibucaine test:
Local anesthetic that inhibits normal pseudocholinesterase by ~ 80%, but abnormal pseudocholinesterase types will be less inhibited
% inhibited = Dibucaine #
Heterozygous Pseudocholinesterase Defect
50-60% pseudocholinesterase inhibited
Prolonged by 1-2x
Homozygous Pseudocholinesterase Defect
20% pseudocholinesterase inhibited
Prolonged by up to 8 hrs
Other names for Plasma Cholinesterases
Pseudocholinesterases or butyrocholinesterase
