Local Anesthetics Flashcards Preview

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Flashcards in Local Anesthetics Deck (15)
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1
Q

What are the two classes of local anesthetics?

A

amide and ester type

2
Q

What is the approximate pK of LA?

A

8-9

3
Q

Are LAs more ionized or less ionized at physiologic pH?

A

more ionized

4
Q

Where do LA work?

A

intracellular side of VG Na+ channels

5
Q

How do LA get across the cell membrane?

A

non-ionized form crosses
non-ionized form is ionized
ionized form is active on VG Na+ channels

6
Q

What is the active form of LA?

A

ionized

7
Q

What form of LA crosses the membrane?

A

non-ionized

8
Q

LA work on NA channels at what stages:

  • resting
  • open
  • inactivated
A

only open and inactivated

more potent on more active neurons

9
Q

Side effect of LA with regards to circulation?

A

sm. muscle VG Na+ channels also blocked
–>vasodialation
==>faster clearing of drug

10
Q

Why is epinephrine added to more LA preparations?

A

they cause vasoconstriction

11
Q

Where are ester LA metabolized?

A

in plasma

pseudocholinesterase

12
Q

Where are amide LA metabolized?

A

in liver

mixed oxidases

13
Q

What type of LA is more common to produce a hypersensitivity reaction?

A

ester

14
Q

What is a Bier block?

A

IV admin of LA with tourniquet

15
Q

Ester is old and needs PT

A

procaine and

tetracaine are ester LA