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Flashcards in Local Anesthetics Deck (19):
1

type of molecules are local anesthetics

weak bases

2

most active form of local anesthetics at the receptor site and the most penetrable form

most active - cationic form
rapid penetrability - uncharged form

3

why are local anesthetics less effective in infected tissue

they have low pH so very low fraction of non ionized local anesthetics is available for diffusion in the cell

4

drug that works by constricting BV by potentiating the action of NE hence preventing its absorption

cocaine

5

why do local anesthetics contain a constrictor like epinephrine

-reduces system absorption of local anesthetics from the depot site by decreasing blow flow in these areas --> neuronal uptake of drug is enhanced due to higher local drug concentration and system toxic effects are reduced

6

how does epinephrine work in spinal anesthesia

acts on alpha 2 receptors --> inhibits release of substance P --> reduces sensory neuron firing

7

mechanism of local anesthetics

block voltage gated sodium channels

8

relationship between liposolubility with potency and toxicity

the more liposolube, the more potent and the more toxic

9

relationship between pKa and onset of action

the closer the pKa to body pH, the faster the onset

10

what are the ester local anesthetic

Cocaine
Procaine
Tetracaine
Benzocaine

11

what are the amide local anesthetic

Lidocaine
Bupivacaine
Prilocaine
Ropivacaine

12

provides prophylaxis against seizures when large doses of local anesthetic must be given

diazepam

13

how does local anesthetics affect cardiovascular system ...mention exceptions

-block Na channels --> depress cardiac pacemaker activity, excitability, and conduction
-if really high conc, can block Ca channels
-with exception to cocaine, depress cardiac contraction and cause arteriolar dilation --> hypotension

14

what are ways cocaine differ from the other local anesthetics in ways it affects the CVS

-blocks NE uptake --> vasoconstriction and hypertension
-vasoconstriction --> ischemia

15

the most cardiotoxic local anesthetic

Bupivacaine

16

what happens if given large dose of Prilocaine

large dose of prilocaine --> accumulation of metabolite o-toluidine --> converts hemoglobin to methemoglobin

17

what can be given to turn methemoglobin back to hemoglobin (name drug responsible for methemoglobin in first place)

-Prilocaine responsible for methemoglobin

methylene blue can be given to convert methemoglobin back to hemoglobin

18

which set of local anesthetics can give allergic reaction and why (name them)

esters --> metabolized to PABA (paraaminobenzoic acid) derivates --> allergic reactions

Cocaine
Procaine
Tetracaine
Benzocaine

19

which local anesthetic should not given to those on sulfonamide drugs and why

Procaine because it is hydrolyzed to PABA which inhibits action of sulfonamides

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