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FreakinLOCALanesthesia!!! > Part 1-PharmacoDynamicsTWO > Flashcards

Part 1-PharmacoDynamicsTWO Flashcards

1
Q

Inclusion of more ______ in solution has specific benefits: Greater stability, Increased solubility of the initially powdered, drug in water, Ease of sterilization

A

CATIONS

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2
Q

The _________ (____) is a measure of a molecules AFFINITY of hydrogen ions

A

dissociation constant (pKa)

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3
Q

When pH of solution = _____ of the local anesthetic, 50% is cation form and 50% is base form

A

pKa

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4
Q

What is more important in clinical practice-diffusion of the LA molecule or binding to the receptor site?

A

diffusion!

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5
Q

________ of anesthetic action is related to pKa of the LA*

A

Rate of onset

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6
Q

The _______ the pKa, the longer the onset of anesthesia*

A

HIGHER

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7
Q

LA with a high pKa value has very few molecules available in the ______ form at a tissue pH of 7.4

A

base

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8
Q

What are the typical pKa ranges of LA’s?

A

7.7-8.1

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9
Q

Some anesthetics fall outside of the range of usefulness as injectables (pKa is very _____) but are still effective as topical anesthetics…Example: Benzocaine = pKa of ____

A

LOW (a low affinity for H+ ions, and therefore penetrates really well as base, but does not want to become cation for profound anesthesia!)…Benzocaine - pKa of 3.5

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10
Q

Why is bu-piv-a-caine such a long acting anesthetic?

A

lots of base diffuses and converts to cation to block the signal

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11
Q

The higher the percentage of uncharged base at time of injection, the ______ the anesthetic penetrates the membrane.

A

quicker

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12
Q

Most LA solutions have pH between ___ and ___

A

5.5-7

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13
Q

Repeat concept: LA solutions that contain vasoconstrictor are acidified to slow _______ – prolongs period of effectiveness of drug…WHAT IS THE preservative used?

A

oxidation…SODIUM BISULFATE

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14
Q

Which part of the LA solution can cause allergies?

A

Sodium Bisulfate perservative

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15
Q

Whats faster in onset-LA with vasoconstrictor or plain LA?

A

Plain…it is less acidic (no preservatives)

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16
Q

What is the way LA can get past the impenetrable barrier of intact skin?

A

E…M….L….A….eutectic mixture of local anesthetics…REAL slow

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17
Q

Topicals with pH between 5.5 to 6.5 lowers regional pH to below normal = less ____ formed, Diffusion through to free nerve endings is _____, Nerve block is _______

A

base…limited…ineffective

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18
Q

Increasing pH of the topical anesthetic provides more base form (RN) Increases _______ of the topical anesthetic 􏰀 Shelf life ______ as drug pH increases

A

POTENCY….decreases

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19
Q

A peripheral nerve is composed of _______ to ________ of tightly packed axons

A

hundreds to thousands

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20
Q

ANATOMY REVIEW!!! Single nerve cell is called a _______

A

nerve fiber

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21
Q

ANATOMY REVIEW!!! What covers each individual nerve fiber?

A

endoneurium

22
Q

ANATOMY REVIEW!!! Whats the name for bundles of 500 to 1000 nerve fibers??

A

Fasciculi

23
Q

ANATOMY REVIEW!!! What covers the fasciculi?

A

PeriNeurium

24
Q

ANATOMY REVIEW!!! What is the innermost layer of the perineurium?

A

Perilemma

25
Q

ANATOMY REVIEW!!! What is the alveolar connective tissue supporting fasciculi and carrying nutrient vessels?

A

Epineurium

26
Q

ANATOMY REVIEW!!! What is the outer layer of the Epineurium?

A

Epieneural sheath

27
Q

Which anatomical component of the nerve is the GREATEST barrier to the penetration of LA?

A

Perineurium (covering the 500-1000 bundles of fibers)

28
Q

Fasciculi that are located near the surface of the nerve are called _________

A

mantle bundles

29
Q

What are the first type of individual fibers that are reached by LA?

A

mantle bundles

30
Q

Fasciculi found closer to the center of the nerve are called ________

A

core bundles

31
Q

interesting…..Nerve fibers in ______ bundles innervate structures in close proximity to them…..Fibers in _____ bundles innervate structures some distance away from them

A

mantle = close….core = distance

32
Q

EXAMPLE: Inferior alveolar nerve block given near
entrance to the mandibular canal: Fibers in mantle layer innervate ______ region Fibers in core layer innervate ______ mandible (lips, chin and anterior teeth)

A

molar….anterior

33
Q

Structures receiving ____ bundle innervation anesthetize later and with more difficulty

A

core

34
Q

Lack of labial and mental soft tissue signs and symptoms of anesthesia after administration of inferior alveolar nerve block indicates that _____ bundles have not yet been adequately anesthetized

A

core

35
Q

In NO clinical situation are ALL fibers within a peripheral nerve ______

A

blocked

36
Q

What are the two factors for complete block of nerves?

A

adequate volume and concentration of LA

37
Q

________ time : Time from deposition of the anesthetic solution to complete conduction blockade

A

INDUCTION time

38
Q

Review: Drugs with a _____ pKa possess a more rapid onset of action

A

lower

39
Q

What is the cause of potency in an LA? Duration of action?

A

potency = lipid solubility…..duration = degree of protein binding

40
Q

INTERESTING!!! Proteins constitute ___% of nerve membrane

A

10%

41
Q

What property of LA naturally shortens its own duration of action?

A

vasodilation

42
Q

Recovery from LA- which bundles are going to recover faster?

A

mantle much faster than core

43
Q

Where does recovery from LA first occur?

A

proximal to the injection site

44
Q

_______ is slower process than induction

A

Recovery

45
Q

What is happening with the bundles when the Pt can start to feel the LA wearing off? What can we do about it??

A

the mantle bundles are losing their LA…more LA administered will diffuse and numb again

46
Q

WHAT IS increasing tolerance to a drug that is administered repeatedly??

A

Tachyphylaxis!!! (second injection)

47
Q

________ is more likely to develop if nerve function is allowed to return before second injection*

A

Tachyphylaxis

48
Q

Three factors that affect the rate of removal of an LA: 1. Degree of ______ binding 2._______ at the injection site 3. Presence or absence of ________

A

protein….vascularity…..vasoconstrictor

49
Q

a new first- in-class local anesthetic reversal agent…WHAT is the name and what is its MECH of action?

A

ORA - VERSE…its a VASODILATOR

50
Q

Oraverse: Not recommended for children less than __ yrs and/or less than ___lbs

A

6yrs…33lbs

51
Q

Oraverse: What is contraindicated?….What does the label look like?

A

NO contraindications!….Label is GREEN

52
Q

What is the ratio used with OraVerse to LA? What is the MAX?

A

1:1 ratio, but limit 2 OraVerse

FreakinLOCALanesthesia!!! (11 decks)

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