Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

KLowe-Advanced Anes 2 (Rachel's Class) > Local Anesthetics > Flashcards

Local Anesthetics Flashcards

1
Q

Local anesthetics produce ___ (reversible/irreversible) conduction blockade of impulses along the ___ and ___ nerve pathways

A

Local anesthetics produce reversible conduction blockade of impulses along the central and peripheral nerve pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What was the first local anesthetic?

A

Cocaine–1884

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What was the first synthetic ester local?

A

Procaine–1905

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What was the first amide local?

A

Lidocaine–1943

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Chemical structure of local anesthetics–___philic and ___philic portion separated by ___

A

Chemical structure of local anesthetics–lipophilic and hydrophilic portion separated by hydrocarbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lipophilic portion of LA is the ___ ring

A

Lipophilic portion of LA is the benzene ring–necessary for activity!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What part of LA structure is necessary for its activity?

A

Lipophilic benzene ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

___ (ester/amide) intermediate chain = -CO

A

Ester local intermediate chain = -CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

___ (ester/amide) intermediate chain = -NHC-

A

Amide local intermediate chain = -NHC-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Core structure for local anesthetics = a ___ ring and a ___ amine separated by an intermediate ___ group

A

Core structure for local anesthetics = a benzene ring and a quaternary amine separated by an intermediate carbon group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The bond between the benzene ring and the carbon group determines whether the drug is an amide or an ester–T/F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

There are ___ (few/many) lipid layers for local anesthetics to cross

A

There are many lipid layers for local anesthetics to cross

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are (2) types of enantiomers?

A

S and R enantiomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Racemic mixtures contain ___ (one/both) type(s) of enantiomers

A

Racemic mixtures contain BOTH (S and R) types of enantiomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pure isomers contain ___ (one/both) type(s) of enantiomers

A

Pure isomers contain ONE type of enantiomer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the only (2) pure isomer local anesthetics? What enantiomer type are they?

A

-Ropivacaine
-Levobupivicaine
Both are pure isomers, S enantiomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Each enantiomer binds to different receptors or enzymes, which changes pharmacokinetics, pharmacodynamics, and toxicity–T/F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which enantiomer is more beneficial? (R or S?) Why?

A

S enantiomers are more beneficial because they are less neuro- and cardiotoxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do local anesthetics work?–inhibit ___ ions passage through ion-selective ___ channels; this ___ (slows/speeds up) the rate of depolarization; threshold potential ___ (is/is not) reached; action potential ___ (is/is not) propagated

A

LAs inhibit sodium ions passage through ion-selective sodium channels; this slows the rate of depolarization; threshold potential is NOT reached; action potential is NOT propagated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

LAs alter resting membrane potential and threshold potential–T/F?

A

FALSE–LAs do NOT alter resting membrane potential or threshold potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are (2) sodium channel subunits? Which subunit allows ion conduction and binds local?

A
  • Alpha
  • Beta

Alpha subunit allows ion conduction and binds local

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Local anesthetic binds to receptors in ___ (activated/inactivated/both) state(s)

A

Local anesthetic binds to receptors in BOTH activated/inactivated states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When local anesthetics bind to receptors, the cells become ___ (permeable/impermeable) to sodium

A

When local anesthetics bind to receptors, the cells become IMPERMEABLE to sodium

Threshold potential not reached, action potential not propagated as a result

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

LA binding on ___ (internal/external) part of channel is thought to be most important

A

LA binding on INTERNAL part of channel is thought to be most important

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

LA binding to receptors is ___ (strong/weak)

A

LA binding to receptors is WEAK

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

LAs have access to receptors only when in ___ (activated/inactivated) state

A

LAs have access to receptors only when in activated-open state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

More frequent firing = ___ (more/less) opportunity for access

A

More frequent firing = more opportunity for access

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Nerves with more activity = ___ (slower/faster) blockade

A

Nerves with more activity = faster blockade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Other sites of LA action–voltage-dependent ___ ion channels (much ___ [lower/higher] affinity); ___ ion currents (L-type); ___ protein-coupled receptors

A

Other sites of LA action–voltage-dependent potassium ion channels (much LOWER affinity); calcium ion currents (L-type); G protein-coupled receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Cm = minimum concentration required to produce ___ blockade; analogous to ___

A

Cm = minimum concentration required to produce conduction blockade; analogous to MAC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Larger nerve diameter ___ (increases/decreases) Cm

A

Larger nerve diameter INCREASES Cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Higher frequency and higher pH ___ (increase/decrease) Cm

A

Higher frequency and higher pH DECREASE Cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Cm for motor blockade is about ___ Cm for sensory blockade

A

Cm for motor blockade is about twice Cm for sensory blockade

Possible explanation for sensory block without motor block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Epidural vs. spinal–Cm is ___ (increased/decreased/unchanged); allows for direct access to nerves, so ___ (more/less) is needed

A

Epidural vs. spinal–Cm is unchanged; allows for direct access to nerves, so LESS is needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Nodes of Ranvier–must block at least ___, preferably ___

A

Nodes of Ranvier–must block at least 2, preferably 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Order of blockade/differential blockade (ATP-TP-MVP)

A
  • Autonomic
  • Temperature
  • Pain
  • Touch
  • Pressure
  • Motor
  • Vibration
  • Proprioception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Order of blockade/differential blockade (according to Nagelhout)

A
  • Autonomic
  • Superficial pain, touch, temperature
  • Motor function
  • Proprioception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

___ blockade is blockade of some fibers but not others

A

Differential blockade is blockade of some fibers but not others

i.e.: may block B fibers, C fibers, and small/medium A fibers but may NOT block large A fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Differential blockade results in ___thectomy; loss of sensation for ___ and ___; may still have ___ and ___ function

A

Differential blockade results in sympathectomy; loss of sensation for pain and temperature; may still have proprioception and motor function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Pharmacokinetics of LAs–___ (strong/weak) ___ (acids/bases); pK values ___-___; just above physiologic pH, thus get >50% ___ (ionized/unionized)

A

Pharmacokinetics of LAs–weak bases; pK values 7.6-8.9; just above physiologic pH, thus get >50% ionized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What form crosses the lipid bilayer–ionized or unionized?

A

UNIONIZED

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Locals with pKs nearest physiologic pH have a ___ (slower/faster) onset

A

Locals with pKs nearest physiologic pH have a FASTER onset

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is one local anesthetic that is a weak acid?

A

Benzocaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

pKa of benzocaine = ___

A

pKa of benzocaine = 3.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Benzocaine ___ (does/does not) ionize based on pH

A

Benzocaine does NOT ionize based on pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Mechanism of blockade with benzocaine is unknown–T/F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

pKa of lidocaine = ___

A

pKa of lidocaine = 7.9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

pKa = ___% ionized, ___% unionized

A

pKa = 50% ionized, 50% unionized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

If pH of environment is 7.9 and pKa of lidocaine is 7.9, what % is ionized, what % is unionized?

A

If pH of environment is 7.9 and pKa of lidocaine is 7.9, 50% is ionized, 50% is unionized

50
Q

If pH of environment is 7.2 and pKa of lidocaine is 7.9, ___ (more/less) will be ionized, ___ (more/less) will be unionized

A

If pH of environment is 7.2 and pKa of lidocaine is 7.9, MORE will be ionized and LESS will be unionized

Point is that if you inject a weak base into a more acidic pH, you will have more ionized (non-working) and less unionized (working)

51
Q

Adding bicarb [alkalization] to LA allows for ___ (faster/slower) onset by 3-5 minutes; higher pH thought to ___ (increase/decrease) sting of local infiltration

A

Adding bicarb [alkalization] to LA allows for faster onset by 3-5 minutes; higher pH thought to decrease sting of local infiltration

52
Q

Adding bicarb to LA allows for more ___ (ionized/unionized) to cross

A

Adding bicarb to LA allows for more unionized to cross

So you have more working local

53
Q

Absorption of LA into systemic circulation is influenced by ___ of injection, ___age, use of ___, and characteristics of the drug

A

Absorption of LA into systemic circulation is influenced by site of injection, dosage, use of epi, and characteristics of the drug

54
Q

Distribution of LA–1st = large uptake to ___; 2nd = distribution to highly perfused tissue–i.e.: ___, ___, ___; 3rd = distribution to low perfused tissue–i.e.: ___ and ___

A

Distribution of LA–1st = large uptake to lungs; 2nd = distribution to highly perfused tissue–i.e.: heart, brain, kidneys; 3rd = distribution to low perfused tissue–i.e.: muscle and fat

55
Q

___ (amides/esters) are more widely distributed

A

Amides are more widely distributed

56
Q

Placental transfer is influenced by ___ binding

A

Placental transfer is influenced by protein binding

57
Q

What (2) local anesthetics are highly protein bound?

A
  • Bupivacaine
  • Ropivacaine

Proteins are too large to cross placenta, so low risk of fetal transfer with bupi/ropi

58
Q

Which local anesthetic is not as protein bound?

A

-Lidocaine

Higher risk of placental transfer with lido

59
Q

What can occur in the fetus once local anesthetic crosses the placenta?

A

Ion trapping

60
Q

Why do we worry about which vasopressor can cause fetal acidosis?–once unionized local crosses placenta and hits low fetal pH, more drug becomes ___ (ionized/unionized) and ___ (can/cannot) cross back; build up of trapped local in fetal circulation leads to ___ in fetus

A

Once ionized local crosses placenta and hits low fetal pH, more drug becomes ionized and cannot cross back; build up of trapped local in fetal circulation leads to toxicity in fetus

61
Q

Potency is related to ___ solubility

A

Potency is related to lipid solubility

62
Q

More lipid soluble = ___ (easier/harder) to cross lipid bilayer

A

More lipid soluble = easier to cross lipid bilayer

63
Q

What is most important factor for determining onset of LA?

A

Most important for onset of LA = state of ionization

Lipid solubility also relates to onset of LA

64
Q

Duration of action for LA is related to ___ binding and ___ solubility

A

Duration of action for LA is related to protein binding and lipid solubility

65
Q

Higher affinity to proteins and lipids = ___ (stronger/weaker) attachment

A

Higher affinity to proteins and lipids = stronger attachment…drug remains close to the Na+ channels to act longer

66
Q

Metabolism/clearance of LAs–amides = mainly ___ metabolism; minimal ___ excretion of unchanged drug

A

Amides = mainly hepatic metabolism; minimal renal excretion of unchanged drug

67
Q

Amide with fastest metabolism = ___

A

Fastest = prilocaine

68
Q

Amides with intermediate metabolism = ___ and ___

A

Intermediate = lidocaine and mepivacaine

69
Q

Amides with slow metabolism = ___, ___, and ___

A

Slow = etidocaine, bupivacaine, and ropivacaine

70
Q

Ester anesthetics undergo rapid ___ by ___

A

Ester anesthetics undergo rapid hydrolysis by plasma cholinesterases

71
Q

Ester with rapid metabolism/clearance = ___

A

Ester with rapid metabolism/clearance = chloroprocaine

72
Q

Ester with intermediate metabolism/clearance = ___

A

Ester with intermediate metabolism/clearance = procaine

73
Q

Ester with slow metabolism/clearance = ___

A

Ester with slow metabolism/clearance = tetracaine

74
Q

Which ester anesthetic is an exception to rapid hydrolysis and instead undergoes significant metabolism in the liver?

A

Cocaine

75
Q

Metabolites of ester anesthetics are mostly ___ (active/inactive)

A

Metabolites of ester anesthetics are mostly inactive

76
Q

What metabolite of ester anesthetics has been linked to allergic reactions?

A

Paraaminobenzoic acid (PABA) has been linked to allergic reactions

77
Q

What common local injection site contains little to no cholinesterase enzyme? How does this effect ester anesthetics?

A

CSF

Must wait until the drug goes into systemic circulation for hydrolysis

78
Q

Plasma cholinesterase is inhibited in what (5) conditions?–___, ___ disease, increased ___, ___, ___ patients

A
  • Deficiency
  • Liver disease
  • Increased BUN
  • Parturients
  • Chemotherapy patients
79
Q

What are (3) vasoconstrictors that can be added to LAs? Which is superior?

A
  • Epi–superior
  • Phenylephrine
  • Norepi
80
Q

Which vasoconstrictor, when added to LA, can be used as a marker for intravascular injection?

A

Epi

81
Q

Adding epi to LA ___ (increases/decreases) systemic absorption; maintains drug concentration around ___; can prolong lidocaine by ___; no effect to ___; helps to decrease risk of ___

A

Adding epi to LA decreases systemic absorption; maintains drug concentration around nerves; can prolong lidocaine by 1/3; no effect to onset; helps to decrease risk of toxicity

82
Q

Which 2 local anesthetics have no vasodilator activity?

A
  • Cocaine

- Ropivacaine

83
Q

What happens when ropivacaine is given parenterally?–vaso___ activity

A

Vasoconstrictive activity

84
Q

When adding opioids to spinal or epidural, there is a risk for respiratory ___ and oxygen ___

A

When adding opioids to spinal or epidural, there is a risk for respiratory depression and oxygen desaturation

85
Q

What is a preservative free alpha-2 agonist that can be added to enhance neuraxial anesthesia and can be used in combo with opioids?

A

Clonidine

86
Q

Clonidine epidural dose–___ mcg or ___ mcg/kg

A

Clonidine epidural dose–150 mcg or 2 mcg/kg

87
Q

Clonidine added to epidural increases duration of action from ___ to ___ hours

A

Clonidine added to epidural increases duration of action from 1.8 to 5.3 hours

88
Q

Clonidine spinal dose–___-___ mcg

A

Clonidine spinal dose–15-45 mcg

89
Q

Clonidine 45 mcg increases spinal duration from ___ to ___ minutes

A

Clonidine 45 mcg increases spinal duration from 170 to 215 minutes

90
Q

Mixing locals allows for ___ (slower/faster) onset and ___ (shorter/longer) duration

A

Mixing locals allows for faster onset and longer duration

Examples:

  • Lido/bupi
  • Chloroprocaine/bupi
91
Q

Effects of mixing locals are ___, not ___

A

Effects of mixing locals are additive, NOT synergistic

92
Q

Allergic reactions from LAs are rare–T/F?

A

True–<1% allergic reaction

93
Q

Which are more likely to case allergic reaction–amides or esters?

A

Esters d/t PABA metabolite

94
Q

What preservative in some LAs may cause allergic reactions?

A

Methylparaben

95
Q

Is cross sensitivity likely?

A

No

i.e.: if someone had an allergic reaction to an ester LA, it is safe to use an amide LA instead

96
Q

Systemic toxicity is most common from ___ injection, less common from ___

A

Systemic toxicity is most common from IV injection, less common from absorption

97
Q

Magnitude of systemic toxicity is dependent on ___, ___ of site, presence of ___, properties of the drug

A

Magnitude of systemic toxicity is dependent on dose, vascularity of site, presence of epi, properties of the drug

98
Q

Systemic toxicity depends on volume or concentration used–T/F?

A

FALSE–depends on total amount of drug, NOT volume or concentration used

i.e.: 40 ml of 1% or 80 ml of 0.5% – both = 400 mg, so extent of systemic toxicity is equivalent

99
Q

___ progression describes the dose-dependent CNS effects from systemic lidocaine absorption

A

Hadzic’s progression describes the dose-dependent CNS effects from systemic lidocaine absorption

100
Q

Plasma lido concentration 1-5 mcg/ml = ___

A

1-5 mcg/ml = analgesia

101
Q

Plasma lido concentration 5-10 mcg/ml = circumoral ___; ___itus; skeletal muscle ___; systemic ___tension; myocardial ___

A

5-10 mcg/ml = circumoral numbness; tinnitus; skeletal muscle twitching; systemic hypotension; myocardial depression

102
Q

Plasma lido concentration 10-15 mcg/ml = ___ures, un___

A

10-15 mcg/ml = seizures, unconsciousness

103
Q

Plasma lido concentration 15-25 mcg/ml = __nea, ___

A

15-25 mcg/ml = apnea, coma

104
Q

Plasma lido concentration > 25 mcg/ml = CV ___

A

> 25 mcg/ml = CV depression

105
Q

Treatment of seizures from lidocaine toxicity = ___ with oxygen, administration of ___

A

Treatment of seizures from lidocaine toxicity = ventilation with oxygen, administration of benzos

106
Q

Systemic levels of LA are related to blood flow to tissue–T/F?

A

True

107
Q

Fastest to slowest absorption of LA–In Time I Can Please Everyone But Suzi and Sally

A
  • IV
  • Tracheal
  • Intercostal
  • Caudal
  • Paracervical
  • Epidural
  • Brachial plexus
  • Subarachnoid
  • Subcutaneous
108
Q

Transient Neurologic Symptoms (TNS) = moderate to severe pain in lower __, ___, posterior ___; unknown etiology; highest risk after intrathecal ___

A

TNS = moderate to severe pain in lower back, buttocks, posterior thigh; unknown etiology; highest risk after intrathecal lidocaine

109
Q

Cauda Equina Syndrome = diffuse injury across ___ plexus; various degrees of ___ anesthesia; ___ and ___ sphincter dysfunction; ___plegia; related to ___

A

Cauda Equina Syndrome = diffuse injury across lumbosacral plexus; various degrees of sensory anesthesia; bowel and bladder sphincter dysfunction; paraplegia; related to lidocaine

110
Q

Anterior Spinal Artery Syndrome = lower extremity ___ and variable ___ deficit

A

Anterior Spinal Artery Syndrome = lower extremity paresis and variable sensory deficit

111
Q

Cardiotoxicity is ___ (more/less) common than CNS toxicity from LAs

A

Cardiotoxicity is LESS common than CNS toxicity from LAs

Need ~3 times concentration for cardio toxicity to occur

112
Q

Cardiotoxicity = profound ___tension d/t ___ (contraction/relaxation) of arteriolar vascular smooth muscle; direct myocardial ___

A

Cardioxicity = profound hypotension d/t relaxation of arteriolar vascular smooth muscle; direct myocardial depression

113
Q

With what LA might you see cardiac symptoms before CNS?

A

Bupivacaine

114
Q

Treatment of LA toxicity–initial focus = ___ management, 100% ___; ___ suppression–give ___, AVOID ___ if CV instability

A

Treatment of LA toxicity–initial focus = airway management, 100% O2; seizure suppression–give benzos, avoid prop if CV instability

115
Q

Treatment of LA toxicity–management of arrhythmias–avoid ___, ___ blockers, ___ blockers, and ___ anesthetic; reduce epi to < ___ mcg/kg

A

Treatment of cardiotoxicity–management of arrhythmias–avoid vasopressin, calcium channel blockers, beta blockers, and local anesthetic; reduce epi to < 1 mcg/kg

116
Q

Treatment of LA toxicity–lipid emulsion (20%) therapy–___ ml/kg (lean body weight) IV over ___ minute; maintenance dose ___ ml/kg/min; repeat bolus ___ or ___ for persistent CV collapse; double infusion rate to ___ ml/kg/min if BP remains low; continue infusion for at least ___ mins after circulatory stability; upper limit approx ___ ml/kg lipid emulsion over first 30 minutes

A

Treatment of LA toxicity–lipid emulsion (20%) therapy–1.5 ml/kg (LBW) IV over 1 minute; maintenance dose 0.25 ml/kg/min; repeat bolus once or twice for persistent CV collapse; double infusion rate to 0.5 ml/kg/min if BP remains low; continue infusion for at least 10 mins after circulatory stability; upper limit approx 10 ml/kg lipid emulsion over first 30 minutes

117
Q

What locals can cause methemoglobinemia?–___ > 8mg/kg, ___, ___, ___

A

Prilocaine > 8mg/kg, benzocaine, cetacaine, lidocaine

118
Q

What other drugs (aside from local anesthetics) can cause methemoglobinemia?–___, ___, and ___

A

NTG, phenytoin, sulfonamides

119
Q

What happens in methemoglobinemia?–hemoglobin is ___ (oxidized/reduced) to methemoglobin and cannot carry ___

A

Hemoglobin is oxidized to methemoglobin and cannot carry oxygen

120
Q

Treatment of methemoglobinemia = ___

A

Methylene blue

121
Q

Dose of methylene blue to treat methemoglobinemia ___-___ mg/kg IV over ___ minutes

A

1-2 mg/kg IV over 5 minutes

122
Q

Methylene blue–do not exceed ___ mg/kg

A

Do not exceed 7.8 mg/kg

KLowe-Advanced Anes 2 (Rachel's Class) (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions