Local anesthetics

Question 1

Where do local anesthetics bind?

Answer 1

To sodium channels in nerves

Question 2

For what can local anesthetics be used?

Answer 2

Peripheral nerve blocks
Neuraxial anesthetics
Subq anesthetics
Topical anesthetics

Question 3

How many nodes need to be blocked on myelinated fibers?

Answer 3

3 nodes of Ranvier

Question 4

What is the easiest type of nerve to block?

Answer 4

Small, myelinated fibers

Question 5

What three types of fibers are there?

Answer 5

A, B, and C

Question 6

Subclasses of A fibers

Answer 6

Alpha
Beta
Gamma
Delta

Question 7

Are A fibers myelinated?

Answer 7

Yes

Question 8

Alpha fibers have __ function

Answer 8

motor

Question 9

Beta fibers have __ function

Answer 9

tactile and proprioceptive

Question 10

Gamma fibers have __ function

Answer 10

muscle tone

Question 11

Delta fibers have __ function

Answer 11

pain, cold temperature

Question 12

Are B fibers myelinated?

Answer 12

Yes

Question 13

B fibers are located __.

Answer 13

on preganglionic sympathetic fibers

Question 14

Are C fibers myelinated?

Answer 14

No

Question 15

C fibers function in __.

Answer 15

visceral pain

Question 16

Local anesthetics preferentially bind to which states of receptors?

Answer 16

Inactivated and open states; frequency dependent blockade

Question 17

What type of molecule are almost all local anesthetics?

Answer 17

Amides or esters (almost always amides for non-anesthesiologists)

Question 18

Where do local anesthetics bind?

Answer 18

On the cytoplasmic side of the receptor

Question 19

What adjunct is added to lidocaine to increase absorption and duration?

Answer 19

Epinephrine

Question 20

What happens with neurotoxicity of LA?

Answer 20

Seizures

Question 21

What worsens neurotoxicity of LA?

Answer 21

Acidosis

Question 22

Direct neural toxicity

Answer 22

Irreversible injury to nerve tissue

Question 23

Allergic reactions of LA are generally due to this type

Answer 23

Esters

Question 24

What type of reaction happens?

Answer 24

Type I or type IV

Question 25

If someone says they have an allergy to an amine, what is it actually generally from?

Answer 25

An additive in the LA

Question 26

What relationship determines the speed of onset of the LA?

Answer 26

The pH to the pKa: pKa should be higher so there is more uncharge form that can traverse the membrane

Question 27

How is cardiovascular toxicity treated?

Answer 27

With intralipid; creates a “sink” that LA can be sequestered into