Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Part 3 – PM3B COPY T > (PM3B) Local Anaesthetics > Flashcards

(PM3B) Local Anaesthetics Flashcards

1
Q

What is the resting membrane potential of a cell?

A

-70mV

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

What is the depolarised membrane potential following the overshoot?

A

+50mV

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

How long does an action potential take to generate and be reset?

A

5msec

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

What are the stages of action potential generation?

A

(1) Stimulating current (at -70mV)
(2) Depolarisation
(3) Overshoot (to +50mV)
(4) Repolarisation
(5) Hyperpolarising afterpotential

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

Which major currents determine an action potential?

A

(1) Sodium current
- moves inwards
- depolarising current

(2) Potassium current
- moves outward
- hyperpolarising current

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

Which sodium channel opens following activation?

A

m-gate (depolarisation)

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

Which sodium channel opens following inactivation?

A

h-gate

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

Which potassium channel opens following activation?

A

n-gate

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

What is TTX?

A

Tetrodotoxin

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

Which voltage-gated sodium channels are considered tetrodotoxin (TTX) sensitive?

A

(1) rNav1.1
(2) rNav1.2
(3) rNav1.3

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

Which voltage-gated sodium channels are considered tetrodotoxin (TTX) non-selective?

A

(1) rNav1.7
(2) rNav1.4
(3) rNav1.6

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

Which voltage-gated sodium channels are considered tetrodotoxin (TTX) resistant?

A

(1) rNav1.5
(2) rNav1.8
(3) rNav1.9

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

What are the main structures in cocaine, lidocaine, bupivacaine etc?

A

(1) Aromatic region
(2) Ester/ amide bond
(3) Basic amine

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

Why are cocaine, procaine, and tetracaine considered to be short-acting?

A

Have an ester bond

Esters metabolised by plasma esterases

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

Why are lidocaine and bupivacaine considered to be long-acting?

A

Have an amide bond

Metabolised by liver

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

What are the pathways utilised by local anaesthetics?

A

(1) Hydrophobic
(2) Hydrophilic

Depends on ionisation state of local anaesthetic

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

What is the hydrophilic pathway, in terms of local anaesthetics?

A

Major mode of local anaesthetic action

~90%

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

What is the hydrophobic pathway, in terms of local anaesthetics?

A

Secondary mode of local anaesthetic action

~10%

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

Describe the physicochemical properties of local anaesthetics.

A

Weak bases (pKa ~8-9)

Largely ionised at neutral pH

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

What ionisation of local anaesthetics is required to act?

A

Must cross membrane in unionised form

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

What is use-dependence?

A

More a channel is open the greater the drug block

Increased access to drug binding site

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

How is local anaesthetic action characterised?

A

(1) Duration of action/ degree of tissue penetration
(2) Use-dependent block of sodium channels

(3) Preferential block of small diameter nerve fibres
- nociceptive C and A-delta fibres are blocked more readily than Aß fibres

(4) Preferential block of inactivated state of sodium channels
- Local anaesthetics have a higher affinity for inactivated state

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

Describe the onset of action of cocaine.

A

Medium

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

Describe the onset of action of procaine.

A

Medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe the onset of action of lidocaine
Rapid
26
Describe the onset of action of tetracaine.
Very slow
27
Describe the onset of action of bupivacaine.
Slow
28
Describe the onset of action of prilocaine.
Medium
29
Describe the onset of action of articaine.
Rapid
30
Describe the duration of action of cocaine.
Medium
31
Describe the duration of action of procaine.
Short
32
Describe the duration of action of lidocaine.
Medium
33
Describe the duration of action of tetracaine.
Long
34
Describe the duration of action of prilocaine.
Medium
35
Describe the duration of action of articaine.
Short
36
Describe the tissue penetration of cocaine.
Good
37
Describe the tissue penetration of procaine.
Poor
38
Describe the tissue penetration of lidocaine.
Good
39
Describe the tissue penetration of tetracaine.
Moderate
40
Describe the tissue penetration of bupivacaine.
Moderate
41
Describe the tissue penetration of prilocaine.
Moderate
42
Describe the tissue penetration of articaine.
Good
43
What are the main undesirable effects of cocaine?
CV + CNS effects Due to block of amine uptake
44
What are the main undesirable effects of lidocaine?
Same as cocaine Less tendency to cause CNS effects
45
What are the main undesirable effects of procaine?
Same as cocaine Less tendency to cause CNS effects
46
What are the main undesirable effects of tetracaine?
Same as cocaine Less tendency to cause CNS effects
47
What are the main undesirable effects of bupivacaine?
Same as cocaine Less tendency to cause CNS effects Greater tendency to cause cardiotoxicity
48
What are the main undesirable effects of prilocaine.
No vasodilator activity
49
What are the main undesirable effects of articaine?
Same as cocaine Less tendency to cause CNS effects
50
What are the main undesirable effects of articaine?
Same as cocaine Less tendency to cause CNS effects
51
Describe the duration of action of articaine.
Short
52
Describe the tissue penetration of cocaine.
Good
53
Describe the tissue penetration of procaine.
Poor
54
Describe the tissue penetration of lidocaine.
Good
55
Describe the tissue penetration of tetracaine.
Moderate
56
Describe the tissue penetration of bupivacaine.
Moderate
57
Describe the tissue penetration of prilocaine.
Moderate
58
Describe the tissue penetration of articaine.
Good
59
What are the main undesirable effects of cocaine?
CV + CNS effects Due to block of amine uptake
60
What are the main undesirable effects of lidocaine?
Same as cocaine Less tendency to cause CNS effects
61
What are the main undesirable effects of procaine?
Same as cocaine Less tendency to cause CNS effects
62
What are the main undesirable effects of tetracaine?
Same as cocaine Less tendency to cause CNS effects
63
What are the main undesirable effects of bupivacaine?
Same as cocaine Less tendency to cause CNS effects Greater tendency to cause cardiotoxicity
64
What is IV regional anaesthesia?
Injected into limb Local anaesthesia diffuses rapidly to desired site of action Systemic toxicity prevented by a cuff
65
Why may inflamed tissue be resistant to local anaesthesia action? Why?
Inflamed tissue becomes acidic Local anaesthesia action is pH dependent (pKa ~8-9) - more acidic = more ionised - meaning less local anaesthesia entry - less block
66
When is cocaine used therapeutically?
Rarely Upper respiratory tract
67
When is procaine used therapeutically?
No longer used First synthetic agent
68
When is lidocaine used therapeutically?
Widely used for local anaesthesia + ventricular dysrhythmias
69
When is tetracaine used therapeutically?
Spinal + corneal anaesthesia
70
When is bupivacaine used therapeutically?
Widely used due to long duration of action Levobupivacaine used more commonly (racemate) - causes less cardiotoxicity - causes less CNS depression
71
When is prilocaine used therapeutically?
Widely used NOT in obstetric analgesia - risk of methaemoglobinaemia
72
What is articaine used therapeutically?
Dentistry
73
What are some potential routes of local anaesthesia?
(1) Surface anaesthesia (2) Infiltration anaesthesia (3) Nerve block anaesthesia (4) Spinal anaesthesia (5) Epidural anaesthesia (6) IV regional anaesthesia
74
What is surface anaesthesia?
Applied directly to mucous membrane Solution/ spray/ lozenge/ cream e. g. - lidocaine to mouth - tetracaine to cornea - lidocaine/ prilocaine cream to skin
75
What is infiltration anaesthesia?
Injected directly into tissue Anaesthetises nerve ending e.g. lidocaine/ prilocaine for wound stitching + minor surgery Danger of systemic toxicity - use vasoconstrictors concomitantly
76
What is nerve block anaesthesia?
Injected CLOSE TO nerve trunk Anaesthetises whole area of nerve distribution e.g. bupivacaine block of mandibular nerve in dental surgery Can be used to relieve neuropathic pain
77
What is spinal anaesthesia?
Injected into subarachnoid space (intrathecal) Between 2nd + 5th vertebrae e.g. bupivacaine/ levobupivacaine/ ropivacaine Used in Caesarean section/ rectal surgery Long duration of action
78
What is epidural anaesthesia?
Injected directly into epidural space e.g. bupivacaine in obstetrics
79
Why may inflamed tissue be resistant to local anaesthesia action? Why?
Inflamed tissue becomes acidic Local anaesthesia action is pH dependent (pKa ~8-9) - more acidic = more ionised - meaning less local anaesthesia entry - less block
80
(1) Will local anaesthesia have more action on a rapidly conducting nerve or a slower conducting nerve? (2) Why?
(1) Rapidly conducting nerve (2) Local anaesthesia is use-dependent - higher frequency = more opening - leads to more local anaesthesia entry - means greater depth of block - also promotes inactivity, where local anaesthesia have greater affinity

Part 3 – PM3B COPY T (33 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions