Local Anesthetics

Question 1

what is the action of local anesthetics?

Answer 1

suppress pain by blocking impulse conduction (block sodium channels) along axons (in all neurons they have access to)

Question 2

what neurons are affected with local anesthetic?

Answer 2

only those located near site of administration

Question 3

what neurons are blocked more frequently - myelinated or non-myelinated?

Answer 3

non-myelinated

Question 4

what sensation is lost first?

Answer 4

pain

Question 5

what other sensations are lost?

Answer 5

warmth, touch, and deep pressure

Question 6

what is the advantage of using local anesthetic instead of general anesthetic?

Answer 6

pain can be suppressed without causing local generalized depression of the entire nervous system
- also less risks than general

Question 7

what is methemoglobinemia?

Answer 7

• blood disorder

- Hb modified so it cannot release oxygen to tissues

Question 8

can methemoglobinemia be fatal??

Answer 8

yes

Question 9

what is methemoglobinemia caused by?

Answer 9

topical benzocaine (not for kids under 2 years)

Question 10

what is procaine?

Answer 10

an ester-type anesthetic

Question 11

how is procaine given?

Answer 11

by injection

Question 12

what is given with procaine to delay the absorption?

Answer 12

epinephrine

Question 13

what does procaine increase the risk of?

Answer 13

allergy

Question 14

what is lidocaine?

Answer 14

amide-type agents

Question 15

what are the routes of lidocaine?

Answer 15

topical and parenteral

Question 16

what can result from lidocaine?

Answer 16

cardiac and CNS toxicity

Question 17

what does lidocaine inactivate?

Answer 17

hepatic metabolism

Question 18

what can lidocaine treat?

Answer 18

dysrhythmias

Question 19

what is infiltration anesthesia?

Answer 19

directly into immediate area of Sx or manipulation

Question 20

what is nerve block anesthetic?

Answer 20

• small dose of anesthetic injection into or near the nerves that supply the surgical field

Question 21

where is intravenous regional anesthetic get injected into?

Answer 21

distal vein in arm or leg

Question 22

how do you prevent intravenous regional anesthetic from entering the rest of the circulation from the limb?

Answer 22

tie a tourniquet to the limb

Question 23

what are ester type agents?

Answer 23

contain ester linkage in their structure

Question 24

where are ester like agents metabolized?

Answer 24

in blood

Question 25

what is an example of an ester type agent?

Answer 25

procain (novocain)

Question 26

what are amide type agents?

Answer 26

aminde linkage

Question 27

what are amide type agents metabolized?

Answer 27

enzymes in the liver

Question 28

what is an example or amide type agents?

Answer 28

lidocaine (xyloxaine)