Local Anesthetics - the drugs Flashcards Preview

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

Its metabolite interferes with efficacy of sulfonamide antibiotics

A

Procaine

2
Q

what LAs have significant 1st pass effect by the lungs

A

Bupivicaine

Lidoicaine

Prilocaine

3
Q

Chloroprocaine duration after infiltration

A

30 min to 1 hr

4
Q

LAs that come as pure enantiometrs

A

Ropivacaine

Levobupivacaine

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

5
Q

What is the dose of Lidocaine for epidural placement?

A

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
Q

Chloroprocaine Max Dose

A

12 mg/kg

7
Q

Lidocaine uses?

A
  • Regional/ neuraxial block
  • Cough suppression
  • Attenuate ICP/BP raise during laryngoscopy
  • Attenuate reflex bronchospasm that may occur with airway instrumentation
  • Suppress ventricular dysrhythmias
8
Q

Tetracaine Max Dose

A

3 mg/kg

9
Q

Cocaine toxicity sxs

A

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

  • restlessness, tremors, seizures & euphoria
  • tachycardia/MI
10
Q

LAs that come in racemic mixtures

A

Bupivacaine

Mepivacaine

11
Q

Arrange LAs in the order of non-ionization %

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

A

Procaine 3%

Chloroprocaine 5%

Tetracaine 7%

Cocaine 7%

Bupivacaine/Levobupivacaine 17%

Ropivacaine 17%

Lidocaine 24%

Prilocaine 24 %

Mepivacaine 39%

12
Q

Bupivacaine E½t

A

3.5 hrs

13
Q

LA great for differential nerve block (sensory>motor)

great for OB

A

Bupivacaine

14
Q

when do you redose lidocaine (epidural)?

A

lidocaine lasts about 1.5-2 hours etc

15
Q

Ropivacaine max spinal dose

A

15-20

16
Q

Bupivacaine DOA after spinal

A

1.5 to 3.5 hr

17
Q

List max doses of LAs

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

A

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
Q

Prilocaine duration after infiltration

A

1 -2 hrs

19
Q

Mepivacaine duration after infiltration

A

1.5 - 3 hr

20
Q

LAs with pKa in the ≈ 8s

A

Bupivacaine/Levobupivacaine 8.1

Ropivacaine 8.1

Cocaine 8.5

Tetracaine 8.5

Chloroprocaine 8.7

Procaine 8.9

21
Q

which has more CNS toxicity poptential

lidocaine or mepivacaine

A

mepivacaine

22
Q

Does lidocaine have an active metabolite?

A

YES.

2 Monoethylglycinexylidide (80% activity)

(Mono-ethyl-glycine-xylidide)

xylidide (10% activity)

23
Q

Bupivacaine (Levobupivacaine)

duration after infiltration

A

4-8 hrs

24
Q

LAs with pKa in the ≈7s

A

Mepivacaine 7.6

Etidocaine 7.7

Lidocaine 7.9

Prilocaine 7.9

25
Q

Shortest DOA for epidural

A

Chloroprocaine

26
Q

Ropivacaine duration after infiltration

A

4-8 hrs

27
Q

LA toxicity s/s?

A

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
Q

Lidocaine max spinal dose

A

30-100 mg

29
Q

Bupivacaine pros and cons?

A

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
Q

metabolism of prilocaine.

A

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
Q

Bupivacaine solution concentration

A

Spinal 0.5 - 0.75%

Epidural 0.0625 - 0.5%

Peripheral nerve block 0.25 - 0.5%

32
Q

LAs that cannot be give epidurally

A

Procaine

Tetracaine

33
Q

Lidocaine onset and DOA w/ epidural

A

onset 5-15 min

DOA 90-130 min

34
Q

what LAs are highly lipid soluble

A

Bupivicaine

Etidocaine

Tetracaine

BET

35
Q

Lidocaine Max Dose

A

4 mg/kg

7 mg/kg with epi

36
Q

Chloroprocaine onset and DOA w/ epidural

A

onset 5-15 min

DOA 30-90 min

37
Q

most cardiotoxic LA

A

Bupivacaine

38
Q

LAs that cannot be given in aperipheral block

A

Tetracaine

39
Q

Lidocaine solution concentrations

topical

regional IV

PNB

Spinal

Epidural

A

topical 4%

regional IV 0.25-0.5%

PNB 1-2 %

Spinal 1.5 - 5%

Epidural 1.5 - 2%

40
Q

Mepivacaine onset and DOA w/ epidural

A

onset 2-15 min

DOA 1 - 3 hrs

41
Q

Mepivacaine Max Dose

A

4 mg/kg

7 mg/kg with epi

42
Q

What is chloroprocaine used for?

A

OB epidurals

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

43
Q

LAs that can be given IV

A

Lidocaine

Prilocaine

44
Q

How is cocaine metabolized?

A

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

careful with renal disease

NOT PAVA like the other esters

45
Q

Long DOA for an ester

A

Tetracaine

1.5 - 3.5hrs

46
Q

Mepivacaine max spinal dose

A

40-80 mg

47
Q

Bupivicaine max spinal dose

A

15-20 mg

48
Q

pt cannot have epi

what LA is best alternative

A

Mepivacaine

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

49
Q

Bupivacaine Max Dose

A

2.5 mg/kg

50
Q

Cocaine Max Dose

A

3 mg/kg

51
Q

Which LAs have slow, moderate, and fast onsets?

A

Slow: procaine, tetracaine (esters)

Intermediate: bupivacaine

Fast: chloroprocaine, lidocaine, etidocaine, mepivacaine

52
Q

Etidocaine Max Dose

A

4 mg/kg

53
Q

LA not effective topically

A

Mepivacaine

54
Q

Tetracaine max spinal dose

A

5-20 mg

55
Q

Ropivacaine Max Dose

A

3 mg/kg

3.5 mg/kg with epi

56
Q

Procaine duration after infiltration

A

45 min - 1 hr

57
Q

Why is lidocaine avoided in spinals?

A

Linked to caudal equina syndrome

Epidural ok to use

58
Q

LAs that are still questionable for a spinal block

A

Chloroprocaine

Lidocaine

Mepivacaine

Prilocaine

59
Q

Procaine max spinal dose

A

100-200 mg

60
Q

Bupivacaine onset and DOA w/ epidural

A

onset 15-20 min

DOA 3 - 6 hrs

61
Q

LAs used topically

A

tetracaine

Lidocaine

62
Q

S (or levo) enantiomer of bupivacaine

A

Ropivacaine

less cardio-toxic