10 Local Anesthetics

Question 1

What is the MOA of local anesthetics?

Answer 1

Na channel blocker

-> reduce frequency of AP

Question 2

What fibers are most affected by local anesthetics?

Answer 2

C- Fibers
Thin
Pain signals

Question 3

What is local anesthesia pKa?

Answer 3

8-9

Question 4

What happens with local anesthetics when there is an infection or inflammation?

Answer 4

Theres a lower pH

More drug is required

Question 5

How do you increase the amount of local anesthetic ale to cross the membrane?

Answer 5

Increase pH – more local becomes available

Question 6

How is local anesthesia injected into the tissue?

Answer 6

Extravenous injection

Question 7

What volume is required for spinal and epidural anesthesia?

Answer 7

Spinal - low

Epidural - large

Question 8

What drug is used to decrease the rate of systemic absorption of a local anesthetic?

Answer 8

EPI – Vasoconstrictors

Inc potency

Question 9

What local anesthetics belong to the Ester class?

Answer 9

Cocaine

Procaine

Benzocaine

Tetracaine

Question 10

What local anesthetics belong to the Amide class?

Answer 10

Lidocaine

Mepivicaine

Bupivaciane

Ropivacaine

Question 11

How are esters metabolized?

Answer 11

Pseudocholinesterase

Question 12

How are amides metabolized?

Answer 12

Cytochrome p450

Question 13

What is the only local anesthetic that causes vasoconstriction? Why?

Answer 13

Cocaine

Inhibits NE uptake and catecholamine

Question 14

How is cocaine used?

Answer 14

Topically by ENT

Question 15

What are signs of cocaine OD?

Answer 15

excitement

reslessness

confusion

tremor

Question 16

What toxicity is caused by cocaine?

Answer 16

Cardiotoxic

Question 17

What is the greatest vasodilator of all local anesthetics?

Answer 17

Procaine (Novocain)

Question 18

What is cocaines onset and duration?

Answer 18

rapid onset

medium duration

Question 19

What is Procaines potency, onset, & duration?

Answer 19

potency= low

onset= slow

duration= short

Question 20

What local anesthetic has a high incidence of allergy?

Answer 20

Procaine

Question 21

What local anesthetic has the greatest potential for systemic toxicity?

Answer 21

Tetracaine

Question 22

What is tetracaine used for?

Answer 22

Spinal anesthesia

Question 23

What is Tetracaine onset & duration?

Answer 23

onset= slow

duration= long

Question 24

Why is Benzocaine used topically?

Answer 24

Poor solubility in water

Poor absorption

High toxicity if absorbed

Question 25

What is Lidocaine onset & duration?

Answer 25

onset= rapid

duration= intermediate

Question 26

What are signs of Lidocaine OD?

Answer 26

drowsy

loss of consciousness

respiratory arrest

Question 27

What is Lidocaine used for?

Answer 27

I.V. Anti-arrythmic drug

for ventricular arrhythmias

Question 28

What is Mepivacaine onset & duration?

Answer 28

onset= rapid

duration= intermediate

Question 29

What are the toxicities of Mepivacaine?

Answer 29

Toxic for neonates

Crosses placental barrier

don’t use for labor!

Question 30

What is Bupivacaine onset & duration?

Answer 30

onset= slow

duration= long

Question 31

What is Bupivacaine used for?

Answer 31

Labor epidural

Question 32

What is Bupivacaine toxicity?

Answer 32

Cardiac

Question 33

What is Ropivacaine onset & duration?

Answer 33

onset= slow

duration= long

Question 34

What is Ropivacaine used for? Why?

Answer 34

Labor epidural

Less toxic than bupivacaine