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Summer Pharm (2016) ** > Local Anesthetics - the drugs > Flashcards

Flashcards in Local Anesthetics - the drugs Deck (62):
1

Its metabolite interferes with efficacy of sulfonamide antibiotics

Procaine

2

what LAs have significant 1st pass effect by the lungs

Bupivicaine

Lidoicaine

Prilocaine

3

Chloroprocaine duration after infiltration

30 min to 1 hr

4

LAs that come as pure enantiometrs

Ropivacaine

Levobupivacaine

*advantage = less toxic, easier to resuscitate in case of toxicity

5

What is the dose of Lidocaine for epidural placement? 

It depends on the level of blockade required and the density of blockade required. If you want profound motor blockade at T4 for example and the epidural is placed at the L2-3 interspace that is about 10 segments. Say this person is average size – I would give 1.5ml per segments I wanted blocked – so I would give 15cc of 2% lidocaine. 15cc X 20mg/cc = 300mg of lidocaine.  I would need to make sure that this amount did not exceed the maximum dose allowed which is 5mg/kg for plain lidocaine. If the patient was 70kg that is 350mg – so 15cc is O.K. If I wanted to give more I might add epi which would increase my maximum dose to 7mg/kg or 490mg. 

6

Chloroprocaine Max Dose

12 mg/kg

7

Lidocaine uses?

  • Regional/ neuraxial block
  • Cough suppression
  • Attenuate ICP/BP raise during laryngoscopy
  • Attenuate reflex bronchospasm that may occur with airway instrumentation
  • Suppress ventricular dysrhythmias

8

Tetracaine Max Dose

3 mg/kg

9

Cocaine toxicity sxs

cocaine ↓ reuptake of NE → leads to ↑ concentrations of NE

  • restlessness, tremors, seizures & euphoria
  • tachycardia/MI

10

LAs that come in racemic mixtures

Bupivacaine

Mepivacaine

11

Arrange LAs in the order of non-ionization %

cocaine, lidocaine, mepivacaine, chloroprocaine, prilocaine, ropivacaine, tetracaine, procaine

Procaine 3%

Chloroprocaine 5%

Tetracaine 7%

Cocaine 7%

Bupivacaine/Levobupivacaine 17%

Ropivacaine 17%

Lidocaine 24%

Prilocaine 24 %

Mepivacaine 39%

12

Bupivacaine E½t

3.5 hrs

13

LA great for differential nerve block (sensory>motor)

great for OB

Bupivacaine

14

when do you redose lidocaine (epidural)?

lidocaine lasts about 1.5-2 hours etc

15

Ropivacaine max spinal dose 

15-20

16

Bupivacaine DOA after spinal

1.5 to 3.5 hr

17

List max doses of LAs

Bupivacaine, cocaine, tetracaine, ropivacaine, etidocaine, lidocaine, mepivacaine, choroprocaine

Bupivacaine 2.5 mg/kg

Cocaine 3 mg/kg

Tetracaine 3 mg/kg

Ropivacaine 3 mg/kg (3.5 w epi)

Etidocaine 4 mg/kg

Lidocaine 4 mg/kg (7 w epi)

Mepivacaine 4 mg/kg (7 w epi)

Chloroprocaine 12 mg/kg

18

Prilocaine duration after infiltration

1 -2 hrs

19

Mepivacaine duration after infiltration

1.5 - 3 hr

20

LAs with pKa in the ≈ 8s

Bupivacaine/Levobupivacaine 8.1

Ropivacaine 8.1

Cocaine 8.5

Tetracaine 8.5

Chloroprocaine 8.7

Procaine 8.9

21

which has more CNS toxicity poptential

lidocaine or mepivacaine

mepivacaine

22

Does lidocaine have an active metabolite?

YES.

2 Monoethylglycinexylidide (80% activity)

(Mono-ethyl-glycine-xylidide)

xylidide (10% activity)

23

Bupivacaine (Levobupivacaine) 

duration after infiltration

4-8 hrs

24

LAs with pKa in the ≈7s

Mepivacaine 7.6

Etidocaine 7.7

Lidocaine 7.9 

Prilocaine 7.9

25

Shortest DOA for epidural

Chloroprocaine

26

Ropivacaine duration after infiltration

4-8 hrs

27

LA toxicity s/s?

CNS

circumoral numbness, tinnitus, vision changes, dizzy, slurred speech, restless, muscle twitching (especially in the face), seizures (which cause CNS depression, apnea, hypotension)

CV

hypotension, myocardial depression, AV block

Note: bupivacaine is most CV toxic

28

Lidocaine max spinal dose 

30-100 mg

29

Bupivacaine pros and cons?

Pro

highly protein bound

  • low incidence of neuro complications with spinal
  • longer DOA (good for post-op pain and labor)

Also, A alpha, beta, and gamma fibers are not completely blocked, so sensory is blocked and motor is not completely blocked.

Con

TOXICITY! very cardio toxic; pressure is still felt, that can freak people out

30

metabolism of prilocaine.

Rapid metabolism

TOXIC metabolite ortho-toluidine

Must be avoided in OB due to metabolite

Big doses will convert hgb to methemoglobin (treated with methylene blue)

31

Bupivacaine solution concentration

Spinal 0.5 - 0.75%

Epidural 0.0625 - 0.5%

Peripheral nerve block 0.25 - 0.5%

32

LAs that cannot be give epidurally

Procaine

Tetracaine

33

Lidocaine onset and DOA w/ epidural

onset 5-15 min

DOA 90-130 min

34

what LAs are highly lipid soluble 

Bupivicaine

Etidocaine

Tetracaine

BET

35

Lidocaine Max Dose

4 mg/kg

7 mg/kg with epi

36

Chloroprocaine onset and DOA w/ epidural

onset 5-15 min

DOA 30-90 min

37

most cardiotoxic LA

Bupivacaine

38

LAs that cannot be given in aperipheral block 

Tetracaine

39

Lidocaine solution concentrations

topical

regional IV

PNB

Spinal

Epidural

topical 4%

regional IV 0.25-0.5%

PNB 1-2 %

Spinal 1.5 - 5%

Epidural 1.5 - 2%

40

Mepivacaine onset and DOA w/ epidural

onset 2-15 min

DOA 1 - 3 hrs

41

Mepivacaine Max Dose

4 mg/kg

7 mg/kg with epi

42

What is chloroprocaine used for?

OB epidurals

it has an ultra rapid serum hydrolysis (metabolism) which reduces toxicity risk to mom and baby

43

LAs that can be given IV

Lidocaine

Prilocaine

44

How is cocaine metabolized?

Liver, plasma esterases, and about 10-12% eliminated by kidney 

careful with renal disease

NOT PAVA like the other esters

45

Long DOA for an ester 

Tetracaine 

1.5 - 3.5hrs

46

Mepivacaine max spinal dose 

40-80 mg

47

Bupivicaine max spinal dose 

15-20 mg

48

pt cannot have epi

what LA is best alternative

Mepivacaine

it doesn't vasodilate like lidocaine so can be used when avoiding epi

49

Bupivacaine Max Dose

2.5 mg/kg

50

Cocaine Max Dose

3 mg/kg

51

Which LAs have slow, moderate, and fast onsets?

Slow: procaine, tetracaine (esters)

Intermediate: bupivacaine

Fast: chloroprocaine, lidocaine, etidocaine, mepivacaine

52

Etidocaine Max Dose

4 mg/kg

53

LA not effective topically

Mepivacaine

54

Tetracaine max spinal dose 

5-20 mg

55

Ropivacaine Max Dose

3 mg/kg

3.5 mg/kg with epi

56

Procaine duration after infiltration

45 min - 1 hr

57

Why is lidocaine avoided in spinals?

Linked to caudal equina syndrome

Epidural ok to use

58

LAs that are still questionable for a spinal block

Chloroprocaine

Lidocaine

Mepivacaine

Prilocaine

59

Procaine max spinal dose 

100-200 mg

60

Bupivacaine onset and DOA w/ epidural

onset 15-20 min

DOA 3 - 6 hrs

61

LAs used topically

tetracaine

Lidocaine

62

S (or levo) enantiomer of bupivacaine

Ropivacaine

less cardio-toxic