Brainscape's Knowledge GenomeTM

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


See full index

BMB W9 > 10-09 L4 Local anesthetic drugs > Flashcards

10-09 L4 Local anesthetic drugs Flashcards

1
Q

Name the three kinetic phases for sodium channel.

A
  • -Open (active),
  • Closed (inactive),
  • Closed (resting)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Alterations of sodium channel function occur where?

A

LA’s block sodium channels at sites near the intracellular side of the channel.

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

Blocking of sodium channel function is dependent on what two factors?

And what phase do they act on, on the 3 phases?

A
  • Time and voltage dependent
  • LA’s are greater in rapidly firing axons compared to resting fibers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is (are) the most potent sodium blockers?

A

Tetrototoxin (it will kill you!)

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

What are the advantages of local anesethetics?

A
  • They are spontaneous
  • predictable
  • completely reversible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Differential block

A

Different nerve fibers have different sensitivities to LA block.

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

What are the characteristics that nerve fibers affect sensitivity to LA block

A
  • **Fiber diameter: ** thinner fibers more sensitive to block than thicker fibers
  • Firing frequency: rapidly/repetitively firing fibers more sensitive than resting fibers
  • Fiber position in nerve bundle: Outer fibers more sensitive to block than inner fibers.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the most susptible nerve fibers to LA?

A

Type A-Delta and Type C

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

What are LA composed of:

A
  • a lipiophilic group (an aromatic ring)
  • an intermediate chain (an ester or amide)
  • an ionizable group (a tertiary amine: this group is hydrophilic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List the 4 Ester drugs and their time duration.

A
  • Short:
    • Procaine (Novocain)
    • Chloroprocaine (Nesacaine)
    • Cocaine
  • Long:
    • Tetracaine (Pontocaine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

List the 5 different amides and theri duration time.

A
  • **Intermediate: **
    • Lidocaine (Xylocaine)
    • Mepivacaine (Carbocaine)
    • Prilocaine (Citanest)
  • **Long: **
    • Bupivacaine (Marcaine)
    • Ropivacaine (Naropin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are Ester type of LA metabolized in the plasma?

A

Plasma cholinesterases

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

How are Amide linkage LA hydrolyzed? what are the two components that hydrolyzation is dependent on?

A
  • they are hydrolyzed by hepatic cytochrome P450 isoenzymes
    • depenedent on blood flow to the liver and liver fuction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the 5 physiochemical properties of LA? (M-CLIP)

A
  • Molecular Weight
  • Chirality
  • Lipid solubility
  • Ionization
  • Protein binding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the correlation of the pKa and the pH of the LA penetrating the lipid membrane?

A
  • Lower the pKa the less the % ionized
    • thus the more LA molecule can diffuse across the lipid membrane to bind to the intracellular NA channel binding site.
  • the higher the pKa the more the % ionized
    • thus the less LA molecule can diffuse across the lipid membrane to bind to the intracellular NA channel binding site.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the only achiral LA?

A

Lidocaine

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

Which of the following is more potent between S (+) and R (-) isomers?

A
  • S(+) isomer (levobupivacaine) is more potent than R (-) isomer (bupivacaine)
18
Q

What is used to counteract vasodilitory effects?

A

Epinephrine

19
Q

What are topical creams used for?

A

-Starting iv’s -dental procedures

20
Q

What are infiltrations used for?

A

Suturing laceration, plastic surgery

21
Q

What are Intravenous (Bier Block) used for?

A

Hand and wrist surgery

22
Q

What are peripheral nerve block used for?

A

Extremity surgery

23
Q

Epidural anesthesia is used for what?

A
  • C-section
  • Lower extremity surgery
  • post-operative analgesia.
24
Q

Who uses spinal anesthesia and why?

A
  • Urology,
  • gynecology,
  • lower extremity surgery

because they are cheap.

25
Q

What does Epinerphrine as an additive do?

A
  • (vasoconstrictor)
    • decreases systemic absorption
  • increases duration.
26
Q

What does sodium bicarbonate as an additive do?

A
  • increases pH,
  • increases proportion of LA in the uncharged form
  • increased lipid solubility and speed of the onset of the block.
27
Q

What does local acidiosis do?

A
  • It decreases diffusion
    • (more LA is in the charged form)
  • produce tachyphaylaxis.
28
Q

What does pregnancy do in terms of LA?

A

It increases the likelihood of LA toxicity.

29
Q

What is important about the highly protein bound LA’s being adminsitered to a pregnant patient?

A
  • Highly bound LA’s (bupivacaine; ropivacaine) poorly cross the placenta at normal concentrations,
  • making them suitable for epidural analgeaisa for labor
30
Q

Why is Chloroprocaine a good choice for anesthesia for emergent delievery?

A
  • Chloroprocaine has a rapid onset
  • rapidly metabolized (reducing the likelihood for fetal toxicity).
31
Q

Neuropathic pain states characterized by rapid repetitive firing of sensory nerve fibers can be treated by what two LA’s?

A

IV (lidocaine) and Oral (mexiletine)

32
Q

Local Anesthetics can lead to cardiovascular toxicity by four ways what are they?

A
  • Blockage of autonomic nerves
    • (hypotension, bradycardia),
  • Direct myocardial depression,
  • cardiac arrhythmias
33
Q

What is used to treat severe cardiotoxicity?

A

Lipid rescue

34
Q

What are the two allergic reactions to LA’s?

A
  • angioneurotic edema
  • Anaphylaxis (most commonly p-aminobenzoic acid, an ester type metabolite)

Allergy to amide-types is extremely rare

35
Q

What is the cause of Methemoglobinemia?

A
  • caused by prilocaine or benzocaine overdosage -o-toluidine:
  • a metabolite of prilocaine, oxidizes hemoglobin to methemoglobin,

pt may appear cyanotic, SpO2 85% regardless of PaO2

36
Q

What would you use to treat a pt that walks in with cyanotic lips, and a SpO2 85%?

A

-pt has methemoglobinemia treat pt with methylene blue 1-2 mg/kg IV

37
Q

Which drug has high surface local anesthetic activity and i_ntrinsic vasoconstrictor actions that reduce bleeing_ in the mucous membranes?

A
  • Cocaine!
38
Q

How does cocaine cause intrinsic vasoconstricor activity?

A
  • blocks the reuptake of noreepinephrine released from sympathetic nerve endings.
  • side note: cocaine has a signifciante surface local anesthetic activity
    • favored for head neck and pharyngeal surgery.
39
Q

What is the side effects of Bupivacaine?

A
  • cardiovascular collapse
    • marked drop in blood pressure
  • arrhythmia
40
Q

Prilocaine is relatively contraindiated in pt’s with cardiovascular or pulmonary disease because of?

A
  • Can cause decompenstion through formation of O-Toluidine
    • O-toluidine converts hemoglobin to methemoglobine
      • pts. appear cyantoic
      • blood= chocolate-colored
    • high plasma leves of methemoglobin have resulted in decompensation in patients with cardiac or pulmonary disease.

BMB W9 (9 decks)

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