Local Anesthetics

Question 1

List the Esters

Answer 1

1 letter i

1. Procaine
2. Tetracaine
3. Cocaine, Benzocaine

Question 2

List the Amides

Answer 2

2 letter i

1. Lidocaine
2. Bupivacaine
3. Levobupivicaine
4. Ropivacaine

Question 3

Esters and Amides MOA

Answer 3

1. Blocks Na+ channels
2. Reduce influx of Na+ ions
3. Prevents depolarization of membrane
4. Blocks conduction of AP

Question 4

Describe the nonionized and ionized relationship

Answer 4

Non-ionized=uncharged=Reaches receptor site

Ionized=Charged=Causes local anesthetic EFFECT

Question 5

How can you accelerate the onset of action of local anesthetic?

Answer 5

Sodium Bicarb

Question 6

How can you PROLONG the duration of SHORTER acting local anesthetic agents?

Answer 6

Epi= Alpha-agonist sympathomimetic

Question 7

What significantly decreases the amount of anesthesia delivered?

Answer 7

Acidic environment:

1. Abscess
2. Infxn

Question 8

How are esters metabolized?

Answer 8

Plasma Cholinesterases=Very rapid

Question 9

How are amides metabolized?

Answer 9

Liver

Question 10

List the fiber types that will respond quicker to local anesthetics?

Answer 10

1. Small fibers
2. Mylenated fibers
3. Fibers located in the periphery

Question 11

Which type of nerve fibers are blocked first?

Answer 11

Delta: Pain, temperature

Question 12

Which type of nerve fibers are blocked last?

Answer 12

Alpha: Proprioception, motor

Question 13

What are the possible ADE/SE’s of Central Neuraxial Techniques (spinal or epidural)

Answer 13

1. Impair respiratory activity d/t motor paralysis

2. Hypotension d/t autonomic nerve blockade

Question 14

What are the disadvantages of motor paralysis during/post surgery?

Answer 14

1. Limit ability to push during delivery (epidural)
2. Increased risk of fall: limits ability to ambulate
3. Bladder dysfunction/urinary retention: residual autonomic block

Question 15

List the order evolution of block components

Answer 15

1. Sympathetic transmission
2. Temperature
3. Pain
4. Light touch
5. Motor block

Question 16

Define Epidural Block

Answer 16

Local anesthetic injected EXTRADURALLY

Question 17

Define Caudal block

Answer 17

Specific epidural block: Needle inserted into CAUDAL CANAL via sacral hiatus

Question 18

Define Perineural block

Answer 18

Injection around PERIPHERAL NERVES

Question 19

Define Spinal block

Answer 19

Injection into CSF in SUBARACHNOID SPACE

Question 20

Why did the FDA ban Bupivacaine in OB?

Answer 20

Cardiotoxicity

Question 21

Bupivacaine antidote

Answer 21

Lipid resuscitation

Question 22

What is the average elimination half-life of Lidocaine?

Answer 22

1.6 hrs

Question 23

What is the elimination half-life of Lidocaine in patient’s with severe liver dz?

Answer 23

6 hrs

Question 24

Amides and Esters CNS Effects

Answer 24

1. Light headedness or sedation
2. Restlessness
3. Nystagmus
4. Tonic-Clonic Sz’s

Question 25

Amides and Esters CV Effects

Answer 25

1. Vasodilator
2. Heart block
3. Arrhythmias
4. Hypotension

Question 26

What is a unique ADE of Prilocaine?

Answer 26

Converts hemoglobin to Methemoglobin

Question 27

How do you manage the ADE’s of Amides/Esters?

Answer 27

IV Diazepam for convulsions

No antidote

Question 28

What is EMLA cream?

Answer 28

Lidocaine 2.5% + Prilocaine 2.5% Topical Cream

Used in kids prior to venipuncture or IV