Neuro 2: Local Anesthetics

Front 1

What is the general method of action of LA?

Back 1

Nerve conduction is blocked by direct application to axon (In Na channels)

Front 2

What slows the uptake into circulation of LA?

Back 2

Vasoconstrictors (Epi)

Front 3

Are LA reversible?

Back 3

YES

Front 4

What type of molecules can cross the nerve membrane?

Back 4

uncharged

Front 5

What type of molecules interact with the Na+ channel receptor?

Back 5

Charged

Front 6

What does activity at the axoplasm occur?

Back 6

When the drug is in its ionized form

Front 7

What do LA do to the threshold?

Back 7

> it

Front 8

What nerve fibers are the most sensitive to a LA?

Back 8

high frequency or pain fibers

Front 9

What drug is used to tx cardiac disease and why?

Back 9

Lidocaine as it is a vasodilator and also slows Na channels in the heart

Front 10

As the LA becomes more lipid soluble, it is more/less potent

Back 10

More

Front 11

What maintain a receptor's sensitivity?

Back 11

PG, Thromboxane and prostacyclin

Front 12

Structurally, what 3 things make up a LA?

Back 12

aromatic ring (lipophilic/hydrophobic), ester or amide linkage and tertiary amine (hydrophilic)

Front 13

Which is metabolized in the liver, amide or ester?

Back 13

Amide

Front 14

Name 3 ester type LA

Back 14

Cocaine, Procaine, Tetracaine

Front 15

Name 2 amide type LA

Back 15

Lidocaine and Mepivacaine

Front 16

What LA is unique due to its vasoconstrictive properties?

Back 16

Cocaine

Front 17

Net lipophilic (Aromatic ring)

Back 17

Slower onset but longer duration of action (loves the receptor)

Front 18

Net Hydrophlic (Tertiary Amine)

Back 18

Faster onset, but shorter duration

Front 19

What determines the route of metabolism?

Back 19

Amide or ester

Front 20

Axoplasmic movement is proportional to what?

Back 20

Hydrophilicity (Tertiary amine)

Front 21

What is the normal ratio of ionized:un-ionized drug in the axoplasm?

Back 21

Same

Front 22

What will the pH of an infected tissue be?

Back 22

acidic

Front 23

What is the significance of acidic infected tissue and a LA?

Back 23

If pH <, > cationic form which < diffusion into nerves, thus < LA effectiveness

Front 24

What occurs in infected tissue that may shorten the duration of action?

Back 24

Vasodilation

Front 25

What allows for smaller nerve fibers to be most sensitive to LA?

Back 25

They have a larger SA:Volume ratio

Front 26

Low potency and short duration

Back 26

Procaine

Front 27

Intermediate potency and duration

Back 27

Lidocaine and mepivacaine

Front 28

High potency and long duration

Back 28

tetracaine

Front 29

Acidification of the urine would promote what?

Back 29

Drug ionization and excretion of weak bases (LA)

Front 30

What is a concern for toxicity of an ester?

Back 30

idiosyncrasy for plasma cholinesterase

Front 31

What is a concern for toxicity of an amide?

Back 31

hepatic dysfunction

Front 32

What 3 LA is epi most effective?

Back 32

Procaine, Lidocaine and mepivacaine

Front 33

What are the initial effects of a CV toxicity and LA?

Back 33

HT and tachycardia

Front 34

What are the intermediate effects of CV toxicity and LA?

Back 34

< cardiac output and HypOtension

Front 35

What is an allergy most likely to in a LA?

Back 35

ester types

Front 36

What is the concern for tissues supplied by end arteries and LA?

Back 36

gangrene (> oxygen consumption stimulated by epi or hypoxia due to vasoconstriction)

Front 37

What LA are effective topically?

Back 37

Cocaine, lidocaine and tetracaine

Front 38

What LA are effective infiltration?

Back 38

Lidocaine and procaine

Front 39

Linkage type of Procaine?

Back 39

ester

Front 40

Linkage type of Tetracaine?

Back 40

ester

Front 41

Linkage type of Cocaine?

Back 41

ester

Front 42

Linkage type of Lidocaine?

Back 42

amide

Front 43

Linkage type of mepivacaine?

Back 43

amide

Front 44

Metabolism of Procaine?

Back 44

hydrolyzed by plasmacholinesterase to PABA

Front 45

What 3 LA are detoxified by the liver?

Back 45

Tetracaine, Lidocaine and Mepivacaine

Front 46

Procaine Lipophilic or hyrophilic?

Back 46

hydrophilic

Front 47

Tetracaine Lipophilic or hyrophilic?

Back 47

Lypophilic

Front 48

Lidocaine Lipophilic or hyrophilic?

Back 48

Hydrophilic

Front 49

Mepivacaine Lipophilic or hyrophilic?

Back 49

Lypophilic

Front 50

Less potent, faster onset, shorter acting

Back 50

Hydrophilic

Front 51

Highly potent, slower onset, longer acting

Back 51

Lipophylic

Front 52

What is the LA choice for IV regional anesthesia?

Back 52

Lidocaine