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Flashcards in Local Anesthetics Deck (63)
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1

What was the first local anesthetic and when was it introduced?

Cocaine- 1884

2

What is unique to cocaine as a LA?

It causes profound vasoconstriction

(others will cause vasodilation)

3

Is cocaine still in use today? If yes, what is it typically used for?

Yes! It is a schedule II drug typically used for nasal surgery in humans (or other highly vascular surgeries)

4

What are the two classifications of LAs?

Ester-CO-

Amide -NHC-

5

What is the general structure of LAs?

Aromatic ring and hydrophilic portion joined by a hydrocarbon chain

They are classified by the hydrocarbon chain

6

What are the esters?

Cocaine, procaine, chloroprocaine, tetracaine

7

What are the amides?

Lidocaine, mepivicaine, bupivicaine, etodicaine, prilocaine, ropivacaine

8

What is the general MOA of LAs?

Bind to sodium channels in nerve membranes slowing rate of depolarization

Threshold potential cannot be reached and action potentials are not propagated

9

T/F: LAs are weak acids.

False- all LAs are weak bases

pK ~7.7-9

10

What kind of tissues will increase ionization of LAs?

Acidic tissues (ie infection esp) which makes them inactive

11

What three things affect potency, onset, and duration?

- pK
- protein binding
- lipid solubility

12

Will a higher or lower pK increase onset time?

Lower- closer to tissue pH

13

Will a greater or lesser affinity to protein binding increase duration of action?

High protein binding affinity

14

Will a higher or lower lipid solubility increase potency?

Higher the lipid solubility, higher the potency

15

What is the only LA that can be given IV or for IVRA?

Lidocaine

16

What is lidocaine onset/duration?

Fast onset, short duration

17

Is lidocaine absorbed transcutaneously?

Yes

18

What are the systemic/IV effects of lidocaine?

1. Antiarrhythmic
2. Decrease MAC
3. Analgesic
4. Free radical scavenger
5. Improves GI motility

19

What is the onset/duration of bupivicaine?

Immediate onset, moderate duration (3-8hr)

20

T/F: Bupivicaine has the lowest cardiovascular toxicity.

FALSE- highest toxicity, do not give IV

21

What is mepivacaine used for?

Nerve blocks, intra-articular analgesia (large animals)

22

What is the onset/duration of mepivacaine?

Fast onset, short duration (1.5-3)

23

What is the onset/duration of ropicacaine?

Intermediate onset, moderate duration (3-8hr)

24

T/F: Ropivacaine is less cardiotoxic than bupivacaine.

True

25

What is procaine commonly used for?

Procaine penicillin G suspensions (PPG)

26

What are tetracaine and proparacaine commonly used for?

Ophthalmic preparations

27

What is benzocaine commonly used for?

Historically used as a laryngeal spray for intubation

28

What does systemic absorption depend on?

1. Site of injection
2. Dosage
3. Drug Characteristics
4. If epinephrine is used

29

What site of injection has the fastest absorption?

Intercostal blocks

30

How are esters metabolized?

Hydrolysis of plasma cholinesterases