Local Anesthetics 1 Flashcards

1
Q

Name the short duration Ester

A

Procaine

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2
Q

Name the long duration Ester

A

Tetracaine

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3
Q

What are the 2 surface action Esters

A
  • Benzocaine
  • Cocaine (medium)
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4
Q

Name the 2 medium duration Amides

A
  • Lidocaine
  • Mepivacaine
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5
Q

Name the 2 long duration Amides

A
  • Bupivacaine
  • Ropivacaine
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6
Q

Name the medium duration ester

A

Cocaine

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7
Q

Which Ester is for Surface Use only

A

Benzocaine

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8
Q
  • Name the highest potency ester
  • Name the lowest potency ester
A
  • Tetracaine
  • Procaine
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9
Q

Name the medium duration Amide used for dental anesthesia

A

Articaine

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10
Q
  • Which ester onsets quickest?
  • Which ester takes longest to onset?
A
  • Procaine
  • Tetracaine
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11
Q
  • Which 2 amides have the shortest onset?
  • Which amide has the longest onset?
A
  • Lidocaine / Prilocaine
  • Ropivacaine
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12
Q

Local Anesthesia

  • Sensory transmission from local area of body to the ___ is blocked
  • Chemically similar agents (esters & amides) block _____ of excitable membranes
  • Administered in which 2 ways?
A
  • CNS
  • sodium channels
  • injection in target area / topical
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13
Q

Local Anesthetics MOA:

  • Block voltage-dependent ____
  • Reduce influx of ______
  • Prevents depolarization of the membrane
  • Blocks conduction of ______
A
  • sodium channels
  • sodium ions
  • action potential
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14
Q

Local Anesthetics MOA:

  • Both ____ and ____ forms of the drug play important roles
  • Which one reaches the receptor site first?
  • Which one causes the effect?
A
  • non-ionized (uncharged) & ionized (charged)
  • non-ionized (uncharged)
  • ionized (charged)
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15
Q

Local Anesthetics MOA:

  • Onset of action may be accelerated by the addition of _____, which enhances intracellular access of these weakly ____ compounds
A
  • sodium bicarbonate
  • basic
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16
Q

Sodium Channel

  • Excitable membrane
  • Sodium ions are not able to pass through the channel when the drug is ______
  • The local anesthetic diffuses within the membrane in its ____ form
  • In the aqueous extracellular and intracellular spaces, the ___ form of the drug is also present.
A
  • bound to the receptor
  • uncharged
  • charged
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17
Q

The lower the pH, (acidic) the ________.

A

harder it is to anesthetize

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18
Q

Local Anesthetics Pharmacokinetics: absorption/distribution

  • Duration of local action is limited unless blood flow to area is ______
  • Administration of an ______ (_____) w/ shorter acting local anesthetic agents prolongs duration**
A
  • reduced
  • alpha-agonist sympathomimetic vasoconstrictor (epinephrine)
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19
Q

Local Anesthetics Pharmokinetics: absorption/distribution

  • _______ agents often do not need a vasoconstrictor (which 3?)
  • Topical local anesthetics dependent on _____ (which 4?)
A
  • Longer acting
    • bupivicaine
    • ropivicaine
    • tetracaine
  • surface activity
    • cocaine
    • benzocaine
    • lidocaine
    • tetracaine
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20
Q

Local Anesthetics PK: Metabolism

  • Ester local anesthetics metabolized by ________ (very rapid)
    • Procaine is fastest / Tetracaine is slowest
  • Amide local anesthetics are metabolized by _____
A
  • plasma cholinesterases
  • the liver
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21
Q
  • Are smaller or larger fibers blocked more easily?
  • Are myelinated fibers or unmyelinated fibers blocked more easily?
  • Are fibers in the periphery of a thick nerve bundle or fibers in the core blocked sooner? Why?
A
  • smaller
  • myelinated
  • periphery, they are exposed earlier to higher concentrations of the anesthetic
22
Q

? Alpha / Beta / Gamma / Delta ?

  • Proprioception, motor
  • Fiber type?
A
  • Alpha
  • Type A
23
Q

? Alpha / Beta / Gamma / Delta ?

  • Touch, pressure
  • Fiber type?
A
  • Beta
  • Type A
24
Q

? Alpha / Beta / Gamma / Delta ?

  • Muscle spindles
  • Fiber type?
A
  • Gamma
  • A
25
Q

? Alpha / Beta / Gamma / Delta ?

  • Pain, temperature
  • Fiber type?
A
  • Delta
  • A
26
Q

Which fiber type?

  • Preganglionic autonomic
A

B

27
Q

Fiber type?

  • Pain
A

Type C / Dorsal root

28
Q

Fiber type?

  • Postganglionic
A

Type C, sympathetic

29
Q

Which nerve fiber?

  • Proprioception (muscle sense)
A

A-alpha

30
Q

Which nerve fiber?

  • touch
A

A-beta

31
Q

Which nerve fiber?

  • pain & temperature
A

A-delta

32
Q

Which nerve fiber?

  • pain, temperature, itch
A

C-nerve

33
Q

Which nerve fiber is largest and which is smallest?

A
  • A: large
  • C: small
34
Q

Differential Block, local anesthesia

  • Capable of what?
  • Central neuraxial techniques (spinal/epidural)
    • Motor paralysis my impair what?
    • Autonomic nerve blockade may promote what?
A
  • blocking all nerves
  • respiratory activity
  • hypotension
35
Q

Differential Block

  • Motor paralysis may be desirable during surgery, but disadvantageous in other settings:
    • Motor weakness due to epidural during obsterical labor may limit ______
    • When used for post-op analgesia
      • hampers a pts ability to _____
      • residual blockade may interefere w/ ____ resulting in ______.
A
  • pt’s ability to bear down (push) during delivery
  • ambulate w/o assistance –> risk of fall
  • bladder function –> urinary retention / need for cath
36
Q

Clinical Block

  • What is the order of block? (5)
  • “Successful” surgical anesthesia may require _____, not just ______.
A
  • sympathetic -> temperature -> pain -> light touch -> motor block
  • loss of touch / ablation of pain
37
Q

Effect of added vasoconstrictors

  • Localized neuronal uptake is enhanced because of higher sustained local tissue concentrations, which translates to —> ______
  • May enable adequate anesthesia for ______
  • Extends duration of _______ and lower total anesthetic requirement
A
  • clinically longer duration block
  • more prolonged procedures
  • post-op pain control
38
Q

Effect of added vasoconstrictors

  • Peak blood levels of anesthetics will be ______, as absorption is more closely matched to metabolism & elimination
  • Risk of systemic toxic effects is _____
A
  • lowered
  • reduced
39
Q

Effect of Added Vasoconstrictors

  • Incorporated into a spinal anesthetic
    • _____ contributes to prolongation of the local anesthetic effect via its _____ properties
    • Exerts a direct analgesic effect mediated by ____ within the spinal cord
A
  • Epinephrine / vasoconstrictor
  • post-synaptic alpha 2 adrenoceptors
40
Q

Epidural Anesthesia

  • FDA banned the use of _______ in obsterics due to _____
  • What is the antidote?
A
  • 0.75% bupivacaine / cardiotoxicity
  • Lipid Resuscitation
41
Q

Clinical use of local anesthetics

  • Minor surgical procedures
  • Spinal anesthesia
  • Produce ____ blockade in ischemic conditions
  • SLow _____ infusion at low concentrations for post-op analgesia
  • IV local anesthetics used for _______
  • Oral & Parenteral forms of local anesth used adjunctively in _____ pain states
A
  • autonomic
  • epidural
  • reducing pain in peri-operative period
  • neuropathic
42
Q

Epinephrine bottles have what color cap?

A

Red

43
Q

Amide Local Anesthetics

  • Blockade of _____, prevents _____
  • _____ metabolism via CYP450
  • Routes: topical, injection
  • Route: rarely ____
  • Which amide has CV effects? (vasodilation, hypotension, arrhythmias)
  • What are the other ADEs?
A
  • Na channels / action potential propagation
  • Hepatic
  • IV
  • Bupivacaine
  • CNS excitiation: seizures
44
Q

Ester Local Anesthetics

  • What is the name of the main one?
  • Which one has intrinsic sympathomimetic actions?
  • Rapid metabolism via _____ (short half lives)
  • Analgesia topical only for ___ and ____
A
  • Benzocaine
  • Cocaine
  • plasma esterases
  • cocaine & benzocaine
45
Q

Ester Local Anesthetics

  • Cocaine ______
  • When abused, has caused what 3 things?
A
  • Vasoconstricts
  1. hypertension
  2. seizures
  3. cardiac arrhythmias
46
Q

Lidocaine metabolism / excretion

  • Average elimination half-life
    • Increased from ___ hours in normal pt to more than ___ hours in pts w/ severe liver disease
    • Prilocaine (fastest) / Ropivacaine (slowest)
  • Decreased ____ elimination
    • in pts w/ reduced ___ blood flow
    • anesthetized w/ volatile anesthetics (which reduce ___ blood flow) slower than anesthetized w/ IV anesthesia
  • Delayed Metabolism
    • Impaired ____ blood flow leading to ____.
A
  • 1.5 / 6
  • hepatic
  • hepatic
  • hepatic
  • CHF
47
Q

Toxicity

  • CNS effects more common in esters or amides?
    • light-headedness / sedation
    • restlessness
    • nystagmus
    • Tonic-clonic convulsions (may lead to ____ w/ resp & CV depression)
A

Amide

  • coma
48
Q

4 cardiovascular effects associated w/ Amide: Lidocaine

A
  • Vasodilator
  • Heart block
  • Arrhythmias
  • Hypotension
49
Q

Individual unique effects:

  • ____ metabolized to o-toluidine-capable of converting hemoglobin to methoglobin
  • ____ type metabolized products can cause ____ formation (so use ___ agent)
  • High concentrations - local neurotoxic action may cause ______
A
  • Prilocaine
  • Ester / antibody / (amide)
  • permanent impairment of function
50
Q

Treatment of Toxicity

  • What is the antidote?
  • Convulsions managed with _____
A
  • No antidotes
  • IV diazepam
51
Q
  • What does EMLA stand for?
  • What is in the mixture?
  • Permits anesthetic penetration of the ____ layer of the skin, producing local numbness
  • Commonly used in _____ to anesthetize the skin prior to venipuncture for IV cath placement
A
  • Eutectic Mixture of Local Anesthetics
  • Lidocaine 2.5% & Prilocaine 2.5%
  • keratinized
  • pediatrics