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GNURS625/Pharmacology for Anesthesia > Nueromuscular Blockers > Flashcards

Nueromuscular Blockers Flashcards

1
Q

T/F: Neuromuscular blockers DO provide anesthetic and analgesics.

A

FALSE

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2
Q

What receptor does acetylcholine work at?

A

Nicotinic Receptor

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3
Q

T/F: Acetylcholine activates both arms of the autonomic system. (Para-sympathetic and sympathetic)

A

TRUE

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4
Q

Choline and Acetyl CoA make what?

A

Acetylcholine

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5
Q

T/F: Acetylcholine is calcium mediated action potential.

A

TRUE

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6
Q

What deactivates Acetylcholine?

A

Acetylcholinesterase –> (Breaks DOWN to acetate and choline)

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7
Q

T/F: On the nicotinic receptor only one ACh alpha receptor has to be filled for the activation of the K+Na-ATP pump.

A

FALSE

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8
Q

Define a depolarizing neuromuscular blocker

A

Depolarize the muscle fiber leaving it constantly stimulated and unable to be affected by ACh.(Succinylcholine)

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9
Q

Define a non-depolarizing neuromuscular blocker.

A

Competitively block Ach from biding to receptors postsynaptically.

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10
Q

Define ED 95.

A

Dose of NMB necessary to produce 95% suppression of the single twitch response
Describes potency during nitrous oxide-barbiturate-opioid anesthesia
With volatile anesthetic: greatly reduced
2x ED95 dose = tracheal intubation

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11
Q

What are the first muscles to go when using a NMB?

A

Small rapidly moving muschels first (Eyes, fingers)

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12
Q

What are the last muscles to go when using a NMB?

A

Abd. muscle (Diaphram)

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13
Q

What is the structure activity relationship of NMB?

A 
Quaternary ammonium
Highly ionized, water soluble
Vd similar to extracellular fluid volume
No CNS effects
Will no absorb orally
Does not cross placenta
Binds to alpha subunit post-synaptically
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14
Q

What structure activity relationship are NOT completely specific?

A

Cardiac muscarinic receptors

Autonomic ganglia nicotinic receptors

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15
Q

Pharmacokinetics of NMB

A

Not highly protein bound

Not effected by volatile anesthetics (PHARMODYNAMICS interaction)

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16
Q

Name one depolarizing drug.

A

Succinylcholine (Only One)

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17
Q

Name a long acting non-depolarizing NMB drug.

A

Pancuronium (Pavulon) (A)

Doxacurium (Nuromax) (B) Pipecuronium (Arduan) (A)

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18
Q

Name intermediate acting non-depolarizing NMB drug.

A

Atracurium (Tracrium) (B)
Vecuronium (Norcuron) (A)
Rocuronium (Zemuron) (A)
Cisatracurium (Nimbex) (B)

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19
Q

Name a short-acting non-depolarizing NMB drug

A

Mivacurium (Mivacron) (B)

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20
Q

What is the onset and duration of succinylcholine?

A

30-60 seconds (Onset)

3-5 minutes (duration)

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21
Q

What is the method of action for succinylcholine?

A

MOA: Binds one or both alpha subunits at nicotinic receptor. Mimics ACh

Minor presynaptic effects

Important postsynaptic effects

Leakage of potassium out of the cell for extended time: Increase K by ~0.5 meq/L

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22
Q

T/F: Succinylcholine has slower hydrolysis which equals longer duration than ACh.

A

True

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23
Q

T/F: Receptors cannot respons to subsequent ACh molecules when succinylcholine is used.

A

TRUE

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24
Q

What occurs during phase 1 blockade of succinylcholine?

A

-Depolarizing block- receptor stimulation
-Decreased contraction in response to single twitch stimulation
-Decreased amplitude by sustained response to continuous stimulation
-TOF ratio >0.7
-Absence of POSTTENANIC facilitation
Augmentation of neuromuscular blockade after reversal agent
Accompanied by fasiculations at onset

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25
T/F: There is no increase in K+ in the blood serum when using succinylcholine?
FALSE
26
What occurs during Phase 2 of Succinylcholine?
Desensitization: Similar to non-depolarizers May be antagonized by a reversal agent Manifests as tachyphylaxis
27
What is the dose of Succinylcholine?
Tracheal Intubation 1 mg/kg IV Minimum Does: 0.56 mg/kg MAX Dose: 1.5 mg/kg
28
Plasma Cholinesterase of Succinylcholine.
Hydrolyzes SCh Metabolite very weak NMB Hydrolyzed again to succinic acid and choline Must diffuse away from the NMJ to plasma to be metabolized Severe liver disease, neostigmine, high estrogen levels reduces amount Reglan inhibits enzyme Increased in obese patients Atypical cholinesterase may be present
29
What are the side effects of Succinylcholine?
Sinus bradycardia, junctional rhythm, sinus arrest Cardiac muscarinic receptors- mimics ACh Increased risk: 2nd dose within 5 minutes Atropine will not help May increase heart rate and BP due to ANS ganglia stimulation
30
What can you do to reduce side effects?
Pretreatment with a non-depolarizer may reduce side effects | All except hyperkalemia
31
Consideration of hyperkalemia with Succinylcholine?
Increased risk Muscular dystrophy Third degree burns Skeletal muscle atrophy or severe trauma Upper motor neuron lesions May develop within 96 hours, last up to 6 months or more Very high risk: male children with undiagnosed myopathy
32
What myalgias of succinylcholine?
Neck, back, abdomen High risk: young adults, minor surgical procedures, early ambulation Unsynchronized contractions? Pediatric patients: Myoglobinuria: possible damage
33
Where might increased pressure may be seen at with Succinylcholine?
``` Intragastric: Inconsistent, possibly related to intensity of fasiculations Increased risk of aspiration Intraocular 2-4 min post-admin Transient Intracranial Low risk, not normally observed ```
34
Generals about nondepolarizing NMB?
MOA: Compete with ACh for alpha subunits at nicotinic receptors Mostly postjunctional Characteristic Responses Decreased twitch response to single stimulus Unsustained response during continuous stimulation TOF ratio <0.7 Posttetanic potentiation Potentiation or other nondepolarizers Antagonism by anticholinesterases
35
Cardiovascular effect of Nondepolarizing NMB?
Histamine release (Atracurium, Mivacurium) Cardiac muscarinic receptors (Pancuronium) Nicotinic autonomic ganglia (mostly SCh) Rarely achieve clinical significance Most have a wide “autonomic margin of safety”
36
What are some critical myopathy with nondepolarizing NMB?
Long term paralysis for mech ventilation (>6 days) Unpredictable duration More common with aminosteroids Higher risk with corticosteroids given
37
What are the allergic responses to nondepolarizing NMB?
Possible cross-sensitivity Single quaternary ammonium groups  less risk than SCh Females have higher incidence Soaps and cosmetics with quat groups desensitize patient
38
T/F: Women are more sensitive to nondepolarizing NMB?
TRUE
39
What is the onset and duration of Pancuronium?
Onset; 3-5 minutes | Duration: 60-90 minutes
40
What is the ED95 of Pancuronium?
0.07 mg/kg
41
What class is Pancuronium?
Long acting | Bisquaternary aminosteroid
42
How is Pancuronium eliminated?
80% through the urine unchanged
43
What metabolite does Pancuronium produce?
3-desacetylpancuronium (half as potent)
44
What are the cardiovascular effects of Pancuronium?
Increase heart rate Increased MAP Increased cardiac output Mechanism: vagal blockade; SNS activation; muscarinic interference Dysrhythmias, esp. in combo with Digoxin
45
T/F: Pancuronium is enhanced by respiratory acidosis.
TRUE
46
Aging will have what effect on Pancuronium?
Reduced clearance
47
What is the onset and duration of Doxacurium?
Onset: 4-6 minutes Duration: 60-90 minutes
48
What class is Doxacurium (Neuromedics)?
Long acting | Benzylisoquinolinium, bisquaternary
49
What is the ED 95 of Doxacurium?
0.03 mg/kg
50
T/F: Doxacurium has no cardiovascular effects.
TRUE
51
T/F: Doxacurium dose will INCREASE with volatile anesthetics.
FALSE
52
What is the onset and duration of Pepecuronium?
Onset: 3-5 minutes Duration: 60-90 minutes
53
What is the ED 95 of Pipecuronium?
0.05-0.06 mg/kg
54
What class is Pepecuronium.
Long acting | Bisquaternary aminosteroid
55
T/F: There are NO cardiovascular and hepatic effects with pipecuronium.
TRUE
56
What about use of Pipecuronium with infants?
Increase potency and shorter duration
57
What is typical of intermediate NDNMB?
Better clearance All have similar onset (except Roc) 1/3 duration of long acting Faster recovery rate than long acting Minimal to no cardiovascular side effects Reliably reversal by anticholinesterase drugs
58
What is the priming principle with intermediate NDNMB?
``` Priming principle Alternative to SCh for intubation 1: Small dose binds spare receptors no clinical effect 2: 4 minutes later deliver the rest deepens the neuromuscular blockade rapidly Just give Roc x1 ```
59
What is the onset and duration of Atracurium?
Onset: 3-5 minutes Duration: 20-35 minutes
60
What class is Atracurium?
Bisquaternary benzylisoquinolinium | (Intermediate acting)
61
What is the ED 95 of Atracurium?
0.2 mg/kg
62
How much Atracurium is protein bound?
82% (albumin)
63
Does Atracurium have a slow clearance effect?
NO (rapid clearance)
64
Describe Hoffman elimination.
Spontaneous at normal body temp and pH Accelerated by alkalosis, slowed by acidosis Both Atracurium and Cisatracurium HE  hydrolysis  HE Laudanosine  Metabolite Independent of renal and hepatic function Safety net of elimination
65
What is laudanosine during the Hoffman elimination?
CNS stimulant Inactive at NMJ Peripheral vasodilation Increase MAC of volatile anesthetics
66
What is the electrophillic acrylates in the hoffman effect?
Capable of damaging cell membranes | Clinical significance unknown
67
T/F; Infants that receive atracurium get half a dose of older children.
True (more sensitive and faster clearance)
68
What cardiovascular effect does atracurium have?
At x3 ED 95 increase HR Decrease MAP
69
T/F: Histamine release occurs with Atracurium?
True
70
What is the onset and duration of Cisatracurium?
Onset: 3-5 minutes Duration: 20-35 minutes
71
What is the ED 95 of Cisatracurium?
0.05 mg/kg
72
What class is Cisatacurium?
Bisquaternary Benzylisoquinolinium | Intermediate
73
T/F; Cisatracuium will have a prolong effect in the obese patient.
True
74
T/F: There is no cardiovascular effect with Cisatracurium.
TRUE
75
T/f: Hoffman elimination occurs with Cisatracurium and Atracuium.
TRUE
76
What is the onset and duration of vecuronium?
Onset: 3-5 minutes Duration: 20-35 minutes
77
What is the ED 95 of Vecuronium?
0.05 mg/kg
78
What class is vecuronium?
Monoquaternary aminosteroid | intermediate
79
T/F:Vecuronium deals both with hepatic and renal clearance.
True
80
What is the metabolite of vecuronium?
* 3-desacetylvecuronium - Half as potent - converted to 3,17-desacetylvecuronium
81
Vecuronium is ___% unchanged in the bile.
40
82
Vecuronium is __% unchanged in the urine.
30
83
T/F: Vecuronium does not have any cardiovascular changes.
TRUE
84
Hypercarbia post injection enhances effect of _________.
Vecuronium
85
Vecuronium has less Vd than ________, but more than _________.
pancuronium, atracurium
86
Vecuronium duration is _______ in infants and _______ in children.
longest, shortest
87
What is the onset and duration of Rocuronium?
Onset: 1-2 minutes Duration: 20 -35 minutes
88
What class is Rocuronium?
Monoquaternary aminosteroid | intermediate
89
What is the dose of rocuronium ED 95.
0.3 mg/kg
90
Rocuronium x3-x4 ED95 mimics ________.
PANCURONIUM
91
Rocuronium is excreted unchanged in the _____.
bile
92
Rocuronium is prolonged in _______ dysfunction.
renal
93
Cardiovascular effect of rocuronium.
Slight vagolytic effect--->no CV effect with rapid infusion. No histamine effect.
94
What is the onset and duration of Mivacurium?
Onset: 2-3 minutes Duration: 12-20 minutes
95
What is the ED 95 dose of Mivacurium
.08 mg/kg
96
What class is mivacurium?
Bisquaternary benzylisoquinolinium | Fast acting
97
T/F: Mivacurium has inactive metabolites.
True
98
Mivacurium is hydrolyzed by ________ _______.
Pasma cholinesterase
99
T/F: Neostigmine reduces plasma cholinesterase?
True
100
T/F; Burn injury has less cholinesterase activity.
True
101
Cardiovascular effect of mivacurium.
- Decrease MAP - Hypotension prominent in hypertensive patients - Possibly risk of bonchospasm.

GNURS625/Pharmacology for Anesthesia (13 decks)

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