Pharmacology of Local Anesthetics Flashcards

1
Q

What class of local anesthetic is longer-acting?

A

Amide LAs - Ester LAs are shorter-acting but potentially less toxic

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

What types of nerve bundles (Mantle/Core) are more susceptible to LAs?

A

Mantle Bundles - they are placed more proximally

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

What is the effect of inflammation on tissue pH?

A

Inflammation lowers tissue pH - thus reducing the effectiveness of most LAs

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

Injection administration of an LA is used to target what nerves?

A

Peripheral nerve endings, nerve trunks, or nerve roots

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

What is the purpose of the inactive form of LAs?

A

Weak bases that can readily cross the cell membrane in order to bind Na+ channels once active

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

How should an LA be administered to target only superficial nerves?

A

Topically

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

What are the Amide LAs?

A

Lidocaine, Prilocaine, Articaine, Bupivacaine

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

True/False. pKa predicts the rate of onset of a LA.

A

True - Lower pKa indicated faster onset while Higher pKa indicated longer onset

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

True/False. LAs have antihistaminic, anticholinergic, and antiarrhythmic effects

A

True - particularly lidocaine

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

Methemoglobinemia is most associated with what LA?

A

Prilocaine

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

What is the effect of lipid solubility on LA potency?

A

The greater the lipid solubility, the more potent the LA

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

What Ester LA is considered the longest lasting and used for spinal anesthesia and ophthalmic procedures?

A

Tetracaine

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

These types of nerve fibers are most susceptible to LAs.

A

Pain > Temperature > Light Touch > Deep Pressure > Proprioception

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

True/False. Myelination has a greater effect on LA effectiveness than fiber diameter.

A

False. Fiber diameter is more influential than myelination

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

How do intrinsic neuronal properties influence the effectiveness of LAs?

A

Small-diameter fibers, myelinated axons, and neurons with hire firing rates are most susceptible to LAs

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

What are the commonly used topical LAs?

A

Lidocaine, Benzocaine (only used topically)

17
Q

A metabolite of this class of local anesthetics may cause serious allergic reactions in some patients.

A

Ester LAs

18
Q

What is neuraxial anesthesia?

A

Administration of an LA directly into the fatty tissue surrounding nerve roots as they exit the spine

19
Q

What is the active form of an LA?

A

Charged cationic form

20
Q

What may be used to reverse cardiac ADRs of LAs?

A

IV lipid infusion

21
Q

This vasoconstrictor has fewer cardiac effects than epinephrine, but potentially interacts with tricyclic antidepressants.

A

Levonordefrin

22
Q

What are the commonly injected LAs?

A

Lidocaine, Bupivocaine, Mepivacine, Procaine

23
Q

What effect does vasodilation have on LA effect?

A

Most LAs as vasodilators. This reduces the time LAs are within tissues and decreases their duration of action

24
Q

What is the effect of low pH on the effectiveness of LAs?

A

Low pH favors the active form of LAs. This means there is less of the LA in inactive form to cross the cell membrane. The result is longer induction and lower effectiveness

25
Q

What vasoconstrictors are commonly administered with LAs?

A

Epinephrine, Levenordefrin

26
Q

What is the only LA that is a vasoconstrictor, rather than vasodilator?

A

Cocaine

27
Q

True/False. Greater protein binding increases the effectiveness of LAs.

A

False. The higher the degree of protein binding, the less effective the LA

28
Q

What is the MOA of LAs?

A

Bind inside voltage-gated Na+ channels to block initiation and propagation of action potentials

29
Q

What are the most common cardiac ADRs associated with LA use?

A

Bradycardia, hypotension, shock

30
Q

What are the common Ester LAs?

A

Procaine, Chloroprocaine, Tetracaine, Benzocaine, Proparacaine