Week 2 Flashcards

1
Q

New FDA law requires LA carpule labeling to say?

A

1.7 mL

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2
Q

Name 2 buffering agents that can be in the carpule

A

sodium hydroxide and sodium chloride

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3
Q

The vasoconstrictor present in the carpule

A

epi or levonordefrin

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4
Q

This vasoconstrictor preservative helps decrease the solution pH to delay the onset of the LA

A

sodium bisulfite

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5
Q

If a pt reported that they had an allergic rxn to a LA before 1984, then what were they probably allergic to?

A

parabens

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6
Q

Esters are metabolized in the ______ while amides are metabolized in the _________

A

blood; liver

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7
Q

T/F: Allergic rxns are rare with esters.

A

False bruh they’re hella common

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8
Q

ALL injectables LAs are?

A

amides

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9
Q

Describe the chemical structure of LAs

A

1) lipophilic aromatic ring
2) intermediate linkage
3) hydrophilic terminal amine

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10
Q

Which part of the chemical structure of LAs determines if it’s an ester/amide?

A

the intermediate linkage

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11
Q

Once the LA has gained a ________ ion, it’s now in it’s ___________ form

A

H+; active

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12
Q

L.A. molecules in the cartridge include anions and cations. How do they differ with their onset?

A

more anions: low pKa, more base, fast diffusion, rapid onset
more cations: high pka, less base, slow diffusion, slow onset

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13
Q

Infected tissues are acidic. What happens if you inject LA into this acidic tissue?

A

since the LA is also acidic, then there will be less molecules that cross the membrane = INADEQUATE ANESTHESIA

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14
Q

L.A. must penetrate _______mm of myelinated nerve length (3-4 nodes of Ranvier) to block a nerve impulse
↑ — of L.A. is required for large nerves (inferior alveolar n.)

A

8-10mm

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15
Q

↑___________ of L.A. is required for large nerves (inferior alveolar n.)

A

volume

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16
Q

Describe the onset if there is a high concentration of the LA and it has a low pKa

A

rapid onset

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17
Q

What happens to the dosage if the lipid solubility decreases?

A

have to increase the dose to enhance diffusion of drug through the nerve

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18
Q

What happens to the duration of the LA if there is increased protein binding?

A

increased duration

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19
Q

T/F: LAs are vasodilators

A

true

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20
Q

Pharmacokinetics of LAs include…. (fat list)

A

1) onset of action
2) induction
3) recovery from block
4) reinjection
5) duration / potency
6) distribution
7) absorption
8) biotransformation (metabolism)
9) excretion
10) systemic effects

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21
Q

period from LA deposit to blocked impulse conduction

A

onset of action

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22
Q

the primary factor of onset of action of a LA

A

pKa!!!
low pKa = rapid onset

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23
Q

secondary factor of onset of action of LA

A

site!
small diameter nerves have rapid onset

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24
Q

primary factor of induction of LAs

A

initial concentration
increased conc = rapid onset

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25
Q

Name some areas in the body where the anesthetic loses concentration from

A

-tissue fluid
-capillaries
-lymphatics
-anatomic barriers

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26
Q

Degree of ____________ to receptor site is primary factor for recovery from LA block

A

binding

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27
Q

T/F: Recovery is a slower process than induction

A

True

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28
Q

What will occur if i try to reinject a pt and their nerve fibers have fully recovered?

A

tachyphylaxis -> the LA is ineffective

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29
Q

3 factors that affect potency of LA

A

1) protein binding
2) vascularity of injection site
3) vasoconstrictor in LA

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30
Q

Examples of highly vascular organs

A

brain
heart
liver
lungs
kidneys

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31
Q

Which route of administration will allow for increased absorption?

A

topical

32
Q

T/F: The presence of a vasoconstrictor increases absorption.

A

false!! it decreases it cuz if you’re constricting the blood vessel aka making the diameter smaller then less flows into bloodstream

33
Q

Biotransformation refers to the ____________ of a drug

A

metabolism

34
Q

Name 3 ester LAs

A
  1. procaine
  2. tetracaine
  3. benzocaine
35
Q

Name 5 amide LAs

A
  1. lidocaine
  2. mepivacaine
  3. bupivacaine
  4. prilocaine
  5. articaine
36
Q

which amide LA has shortest half life?

A

Articaine

37
Q

Why is there an increased risk of systemic toxicity of LAs in severe renal disease?

A

due to build up of drug when not cleared by kidneys

38
Q

Although small amounts of both esters and amides L.A.s are excreted unchanged in urine, which is excreted in a greater percent this way?

A

amides

39
Q

At what point can LAs affect the CNS and CV system

A

after they are absorbed into blood (before metabolized)(↑blood levels = ↑toxicity)

40
Q

Toxicity and adverse reactions of LAs are directly related to what? (9)

A

1) Nature of specific L.A. (vasodilation)
2) Concentration of drug
3) Route of administration
4) Dose administered
5) Rate of injection
6) Vascularity of site
7) Age of patient
8) Weight of patient
9) Health of patient

41
Q

What color is the band for lidocaine -> 2% 1:100,000 epi

A

red

42
Q

Order of selection of LAs

A

1) duration of pain control needed
2) need for post op pain control
3) patient’s health assesment and current meds
4) allergic to the LA or sodium bisulfite
5) need for hemostasis

43
Q

If a pt is allergic to wine, dried fruit, or dried potatoes, they we assume they have a ___________ allergy

A

bisulfite

44
Q

highest dose of epi

A

1: 50,000

45
Q

T/F: Most LAs are short-acting.

A

False! They’re intermediate-acting so they last for about a hour

46
Q

Characteristics of lidocaine

A

-good for hemostasis if 1:50,000 epi
-duration: 60 mins
-good as topical
2-3 min onset
MRD = 500mg

47
Q

Characteristics of mepivacaine

A

-not used for hemostasis
-w/levo it lasts 60 mins
-NOT an effective topical agent
-onset is about 2 mins
-MRD = 400 mg

48
Q

Characteristics of prilocaine

A

-least toxic LA in dentistry
-good for pregnant pts
-risk of methemoglobinemia
-w/ epi it last 60-90 mins
-onset is 2 mins
MRD = 600 mg

49
Q

Characteristics of articaine

A

-very lipid soluble
-good choice in CV and liver disease pts
-have to give with vasoconstrictor
-duration = 45-75 mins
-NOT an effective topical
-onset: 3 mins
MRD: none

50
Q

Which LA is metabolized primarily in the blood? where is the rest of it metabolized?

A

articaine
10% in liver

51
Q

Characteristics of bupivacaine

A

-most potent and most toxic!!!
-good for long treatment
-NOT available w/o epi
-duration: 1.5-3hrs
-NOT an effective topical
-onset: 5-10 mins
-MRD: 90 mg

52
Q

The CNS is very sensitive to high levels of LA because they?

A

readily cross the blood-brain barrier

53
Q

Has this pt suffered from a moderate or high overdose of LAs?
presents with:
increased HR, RR, BP, and also has muscle twitching with tremors

A

moderate

54
Q

Has this pt suffered from a moderate or high overdose of LAs?
presents with:
decreased HR, RR, BP, they’re convulsing and experiencing unconsciousness

A

High!! They progressing to respiratory arrest cuz of CNS depression

55
Q

Has this pt suffered from a moderate or high overdose of LAs?
presents with:
increased HR, RR, BP, headache and feeling lethargic

A

moderate! they have initial cardiovascular stimulation

56
Q

Has this pt suffered from a moderate or high overdose of LAs?
presents with:
decreased HR, RR, BP, slurred speech, disoriented

A

high! progressing to cardiac arrest and cardiac depression

57
Q

4 functions of vasoconstrictors

A

1) constrict blood vessels @ site
2) increase duration of LA
3) provides hemostasis at injection site
4) decrease absorption rate of LA

58
Q

Which vasoconstrictor affects alpha and beta receptors equally?

A

epi

59
Q

T/F: Levonordefrin affects the alpha receptors more.

A

True! 75% is alpha and 25% is beta

60
Q

An overdose usually occurs via which route?

A

intravascular injection

61
Q

symptoms of an overdose

A

1) dysrhytmias
2) dramatic increase in HR
3) increased BP
4) headache
5) hyperventilation
6) tremors
7) anxiety

62
Q

Absolute contraindication for LA

A

allergy

63
Q

Relative contraindications of LA

A

1) H2 receptor blocker
2) beta blocker
3) CNS depressants

64
Q

Absolute contraindications for vasocontrictors

A

basically anything heart related
hypertension
angina
arrythmias
hyperthyroidism
glaucoma

65
Q

Relative contraindications of vasoconstrictors

A

CVD pts
Tricyclic antidepressants
nonselective beta blocker
digitalis

66
Q

MRD is based on:

A

-maximum dose per appointment
-body weight

67
Q

How do we calculate the amount of LA in 1 carpule

A

take the % x 10
take that number x 1.8ml/carpule

68
Q

MRD and AMD of lidocaine

A

MRD: 3.2 mg/lb
AMD: 500 mg

69
Q

What is the MRD of a 120lb pt if you wanna give them lidocaine?

A

MRD of lidocaine is 3.2 so take that x pt’s weight
3.2 x 120 = 384mg of lidocaine is the max dose

70
Q

Calculate the maximum amount of carpules if the pt weighs 120lbs and the max dose is 384 mg of lidocaine.

A

20 x 1.8 = 36mg of lidocaine
384/36 = 10.6 carpules

71
Q

How much lidocaine did you administer if you gave a pt 5 carpules?

A

in one carpule there is 36 mg of 5 x36 = 180 mg of lidocaine

72
Q

MRD and AMD of prilocaine

A

MRD: 4 mg/lb
AMD: 600mg

73
Q

MRD of vasoconstrictor in a healthy patient

A

EPI: 0.2 mg
Levonordefrin: 1 mg

74
Q

MRD of vasoconstrictor in a cardiac or medically compromised patient

A

EPI: .04mg
Levonordefrin: 0.2 mg

75
Q

Calculate the amount of epi in one carpule

A

1:100,000 epi -> .01mg
.01mg x 1.8 = .018 mg epi/carpule

76
Q

Calculate the max amount of epi carpules in a healthy pt and cardiac pt

A

Healthy: 0.2/.018 = 11 carpules max
Cardiac: .04/.018 = 2 carpules max

77
Q
A