Neuromuscular blockers 4

Question 1

What are the two classes of nondepolarizing neuromuscular blockers?

Answer 1

aminosteroid compounds: rocuronium, vecuronium, pancuronium
benzylisoquinolinium compounds: atracurium, cisatracurium, mivacurium

Question 2

Hofmann elimination is base-catalyzed reaction that’s dependent on

Answer 2

normal blood pH & temperature

Question 3

Benzylisoquinolinium compounds undergo

Answer 3

spontaneous degradation in the plasma (Hofmann elimination & non-specific plasma esterases)

Question 4

___________ is a metabolite of both atracurium and cisatracurium

Answer 4

Laudanosine (more so w/ atracurium)

Question 5

Laudanosine can produce

Answer 5

seizures (CNS stimulant)

Question 6

The termination of action for aminosteroid neuromuscular blockers depends on

Answer 6

hepatic metabolism
biliary excretion
and/or renal excretion

Question 7

________________ compounds are better choices for patients with hepatic or renal dysfunction.

Answer 7

Benzylisoquinolinium

Question 8

Atracurium is hydrolyzed by

Answer 8

Hofmann elimination (33%) & non-specific plasma esterases (66%)

Question 9

Cisatracurium metabolism is dependent on

Answer 9

Hofmann elimination

Question 10

Mivacurium is metabolized by

Answer 10

pseudocholinesterase (explains it’s relatively short DOA)

Question 11

Hofmann elimination is faster with

Answer 11

alkalosis & hyperthermia

Question 12

Hofmann elimination is slower with

Answer 12

acidosis and hypothermia

Question 13

Is the metabolite laudanosine a concern in the OR?

Answer 13

no; only concerned with prolonged infusion in the ICU

Question 14

Rocuronium is eliminated through

Answer 14

biliary excretion as an unchanged molecule

Question 15

Vecuronium undergoes

Answer 15

hepatic deacetylation to 3-OH vecuronium (1/2 as potent as parent compound but rapidly metabolized)

Question 16

Pancuronium undergoes

Answer 16

hepatic deacetylation to 3-OH pancuronium (1/2 as potent as parent compound)

Question 17

Rocuronium is metabolized

Answer 17

it’s not!
eliminated via the liver >70% & renal elimination 10-25% & biliary excretion

Question 18

Vecuronium is metabolized

Answer 18

via the liver (30-40%)

Question 19

Pancuronium is metabolized via the

Answer 19

liver (10-20%)

Question 20

List 4 neuromuscular blockers that undergo organ-independent elimination?

Answer 20

atracurium
cisatracurium
mivacurium
succinylcholine

Question 21

Which drugs potentiate neuromuscular blockade? select 3
a. desflurane
b. gentamycin
c. phenytoin
d. mannitol
e. dantrolene
f. hydrocortisone

Answer 21

a. desflurane
b. gentamycin
e. dantrolene

Question 22

Factors that potentiate neuromuscular blockade increase

Answer 22

the difficulty of reversal as well as the risk of residual weakness

Question 23

What are the three groups of potentiating factors for neuromuscular blockade?

Answer 23

drugs
electrolytes
patient factors

Question 24

Patient factors that potentiate neuromuscular drugs include?

Answer 24

hypothermia (decreases metabolism & clearance)
gender (women are more sensitive to the effects of NMBs)

Question 25

Electrolytes that potentiate neuromuscular drugs include:

Answer 25

increased lithium increased magnesium decreased calcium decreased potassium

Question 26

Drugs that potentiate neuromuscular drugs include

Answer 26

volatile anesthetics antibiotics antidysrhythmics local anesthetics diuretics other drugs: dantrolene, cylcosporin, tamoxifen

Question 27

Which local anesthetics potentiate neuromuscular drugs?

Answer 27

probably all of them

Question 28

Which diuretics potentiate neuromuscular drugs?

Answer 28

furosemide

Question 29

What other drugs potentiate neuromuscular drugs?

Answer 29

dantrolene, cyclosporin, tamoxifen

Question 30

Which antidysrhythmics potentiate neuromuscular drugs?

Answer 30

verapamil, amlodipine, lidocaine, quinidine

Question 31

Which antibiotics potentiate neuromuscular durgs?

Answer 31

aminoglycosides polymyxins clindamycin lincomycin tetracycline

Question 32

Which inhaled anesthetic potentiates NMBs the most?

Answer 32

desflurane

Question 33

Which inhaled anesthetic potentiates NMBs the least?

Answer 33

nitrous oxide

Question 34

Which condition precludes the use of pancuronium? a. aortic regurgitation b. hypertrophic cardiomyopathy c. first degree AV block d. bradycardia

Answer 34

b. hypertrophic cardiomyopathy

Question 35

Pancuronium is a _____-

Answer 35

vagolytic (it increases heart rate)

Question 36

________, ___________, ____________ release histamine

Answer 36

succinylcholine, atracurium, & mivacurium

Question 37

The release of histamine leads to

Answer 37

tachycardia & vasodilation

Question 38

Patients who are ___________________ should not receive histamine-releasing drugs unless the clinical benefits outweighs the risk.

Answer 38

sensitive to a higher heart rate or reduced afterload

Question 39

Succinylcholine stimulates ________________ which can produce tachycardia

Answer 39

autonomic ganglia

Question 40

Succinylcholine can also stimulate ______________ which can produce bradycardia

Answer 40

M2 receptors in the SA node

Question 41

Pancuronium is unique in that it has a _________ effect in the SA node

Answer 41

vagolytic effect & stimulates the release of catecholamines

Question 42

The patient with ___________ should not receive pancuronium

Answer 42

hypertrophic cardiomyopathy

Question 43

Which neuromuscular blocker is MOST likely to cause anaphylaxis? a. atracurium b. cisatracurium c. succinylcholine d. rocuronium

Answer 43

c. succinylcholine

Question 44

__________________________ are the most common cause of perioperative allergic reactions

Answer 44

Neuromuscular blockers

Question 45

Which NMBs are associated with the highest incidence of anaphylaxis?

Answer 45

succinylcholine & rocuronium

Question 46

Do neuromuscular blocker drugs have cross-sensitivity?

Answer 46

yes, may occur in up to 70% of those who have experienced a previous allergic response

Question 47

How do allergic reactions develop as a result of NMBs?

Answer 47

the structures of NMBs contain one or more antigenic quaternary ammonium groups that interact with IgE causing mast cell and basophil degranulation

Question 48

It's possible that sensitivity to any NMBs can develop following

Answer 48

exposure to soaps or cosmetics (because they contain antigenic quaternary ammonium groups)

Question 49

What enzyme is measured to diagnose an anaphylactic reaction?

Answer 49

tryptase (an elevated tryptase level reflects mast cell and basophil degranulation (peaks between 15-120 minutes after exposure