Local Anesthetics

Front 1

Prototype amino-amide drug

Back 1

Lidocaine

Front 2

Prototype amino-ester drug

Back 2

Procaine

Front 3

Amino-esters tend to produce this by-product, causing an allergic reaction.

Back 3

PABA (....)

Front 4

The fastest metabolized amino-amide drug

Back 4

Prilocaine

Front 5

Slowest metabolized amino-ester drug

Back 5

Tetracaine

Front 6

Slowest metabolized amino-amide drug

Back 6

Levobupivacaine

Front 7

The most commonly used local anesthetic in dental practice

Back 7

2% Lidocaine HCl with 1:100,000 epinephrine

Front 8

Besides Lidocaine, these 4 amides are also available in dental cartridges.

Back 8

Buprivacaine

Meprivacaine

Articaine

Prilocaine

Hint 8

B.M.A.P.

Front 9

LAs intended for injection within the oral cavity are supplied in:

Back 9

1.8 mL single use cartridges

1.7 mL for articaine

Front 10

List specific amide anesthetics used for parenteral administration.

Back 10

Prilocaine

Buprivacaine

Articaine

Lidocaine

Meprivacine

Hint 10

P.B.A.L.M.

Front 11

Specific anesthetics for surface application

Back 11

Lidocaine / Prilocaine (EMLA)

Benzocaine

Tetracaine

Dyclonine

Cocaine HCl

Hint 11

L. B. T. D. C.

Only L is the amide

Front 12

Amino-ester without an amino terminus.

Back 12

Benzocaine

Hint 12

Starts with a B.

Front 13

Amino-ester with a keto-group instead of an amino terminus

Back 13

Dyclonine

Front 14

What is the major variant of amino-amide anesthetics?

Back 14

bupivacaine

Front 15

The metabolite of Lidocaine

Back 15

xylidides

Front 16

Dysgeusia, drowsiness, dizziness, and tinnitus are all sign of toxicity caused by...

Back 16

Lidocaine

Front 17

The main threat to life from the adverse effects of LA to the Central Nervous System.

Back 17

Respiratory depression

Front 18

Cocaine will induce this effect when injected to the CNS.

Back 18

Euphoria

Front 19

Methemoglobinemia can result from excessive dosage of...

Back 19

Prilocaine

Front 20

Adverse effects of LA to the Cardiovascular System results mainly from

Back 20

Myocardial infarction & vasodilation

Front 21

This adverse effect on the CVS results partly from a direct effect on vascular smooth muscle and partly from inhibition of the sympathetic nervouse sytem.

Back 21

Vasodilatation

Front 22

This adverse effect on the CVS from LA results indirectly from the inhibition of the Na current in cardiac muscle.

Back 22

Myocardial depression

Front 23

Nerve fiber types that are most sensitive to nerve block.

Back 23

Type B: preganglionic autonomic

Typce C:

dorsal root (pain)

sympathetic (postganglionic)

Front 24

The "last to go" from differential nerve block.

Back 24

Skeletal muscle tone and voluntary tension

Front 25

What is the major barrier to LA penetration?

Back 25

Perineum

Front 26

He isolated cocaine.

Back 26

Niemann

Front 27

He introduced Cocaine as an ophthalmic anesthetic

Back 27

Koller

Front 28

He synthesized Procaine from Cocaine because it was associated with dependence.

Back 28

Einhorn

Front 29

List the 2 prerequisites of LA

Back 29

1. Agent must depress nerve conduction

2. Agent must have both lipophilic and hydrophilic properties to be effective by parenteral injection.

Front 30

This property of LA is essential for penetration of the various anatomic barriers existing between an administered drug and its site of action.

Back 30

Lipid solubility

Front 31

This property of LA ensures that a drug will not precipitate on exposure to interstitial fluid.

Back 31

Water solubility

Front 32

This structure of the LA is responsible for the drug's ability to diffuse across membranes in order to be delivered to the target site.

Back 32

Aromatic group with Moderate Hydrophobicity

Front 33

This structure of the LA enables it to be soluble in water so that the agent will not precipitate once it reaches the interstitial fluid.

Back 33

Amino group

Moderately hydrophobic weak bases are effective as LA

Front 34

List the 2 functions of the Intermediate Chain

Back 34

1. Basis for classifying local anesthetic agents into amino amides and amino esters.

2. Separates the amino terminus and the aromatic group

Front 35

Why is epinephrine added to LA for routine dental use?

Back 35

Epinephrine is a vasoconstrictor. It will increase local tissue concentration and local neuronal uptake. It can decrease systemic toxic effects. It will also prolong the duration of the agent's action.

Remember that absorption is aided by greater vascularization. So vasoconstrictors will decrease the vascularization in the area.

Front 36

Why are moderately hydrophobic weak bases effective as LA?

Back 36

At physiologic pH, a significant fraction of the weak base if in the neutral form and because of their moderate hydrophobicity, they can cross membranes to enter nerve cells.

Once the drug is inside the cell, it can rapidly become positively charged, which will have a higher affinity to the sodium channel.

Front 37

Fastest metabolized amino-ester type.

Back 37

Chlorprocaine

Front 38

Major variants of Amino-ester type

Back 38

Cocaine and Benzocaine

Front 39

This LA type has extremely short half-lives

Back 39

Amino-esters

Front 40

This LA type is widely distributed and often sequestered in the lipophilic storage.

Back 40

Amino-amide

Hint 40

lol labo ba ng tanong ko

Front 41

For amino-amide distribution:

... for highly perfused organs such as brain, liver, kidney, heart and ... in moderately well-perfused tissues such as muscle, GIT

Back 41

Initial rapid distribution phase for highly perfused organs

Slow distribution phase for moderately well-perfused tissues

Front 42

METABOLISM

Site of Hydrolysis

Amino-amide: ________ by _____

Amino-ester: _________ by _____

Back 42

Amino-amide: LIVER by P450 isozymes

Amino-ester: BLOOD by pseudocholinesterase

Front 43

EXCRETION

True or False.

There is abundant urinary excretion of the neutral form of LA.

Back 43

FALSE

"Since LA in the uncharged form diffuse rapidly through lipid membranes, little or no urinary excretion of the neutral form occurs."

Front 44

Acidification of urine promotes excretion of LA. How?

Back 44

It promotes ionization of the tertiary amine base to the more water soluble form, which is more readily excreted.

Front 45

What is the primary mechanism of action of LA?

Back 45

Blockage of voltage-gated sodium channels

- interferes both generation and conduction of action potentials

Front 46

Explain why LA activity is strongly pH dependent.

Back 46

Remember:

The agent has to be in neutral form in order to cross the membrane of the nerve cell.

At alkaline pH, there are more neutral forms than ionized forms so there will be greater chances of penetration of the nerve sheath ➡️ more effective anesthetization

At acidic pH, there are more ionized forms than neutral forms. Ionized forms are not membrane permeant ➡️ poor penetration of agent and poor anesthetization.

Front 47

This factor is the primary determinant of intrinsic anesthetic potency.

Back 47

Lipid Solubility

Highly lipophilic compounds tend to penetrate the nerve membrane more easily so MORE LIPOPHILIC = MORE POTENT

Front 48

What is the effect of Protein binding?

Back 48

Increased duration of action

Front 49

What is the effect of diffusibility?

Back 49

It can affect the time of onset of the anesthetic.

An increase in diffusibility will decrease its time of onset

Front 50

Effect of Vasodilator activity?

Back 50

Decreased potency and duration of action

Front 51

Nerve fiber type that is least sensitive to nerve block

Back 51

Type A, Alpha: proprioception, motor

Front 52

True or False.

An increase in myelination of nerve fiber will translate to decreased sensitivity to nerve block.

Back 52

True

Front 53

True or False

Adverse effects are mainly due to the escape of LA into the systemic circulation.

Back 53

True

Front 54

Myocardial depression and vasodilation from adverse effects of LA to the CVS will result to

Back 54

Decreased blood pressure, sudden hypotension

Front 55

Cocaine will cause these effects on the CVS

Back 55

Hypertension, tachycardia, vasoconstriction

(enhancement of sympathetic activity)

Front 56

True or False

The onset, quality, extent, and duration of LAs vary markedly with the technique of administration used.

Back 56

True

Front 57

Identify technique used:

1. Injected into the epidural space of the spinal cord

2. Injected into the tissue; for surgical procedures on small tissue area

3. For topical use

4. Injected around a nerve that leads to the operative site

5. LA injected into the subarachnoid space of the spinal cord

Back 57

1. Epidural anesthesia

2. Local infiltration

3. Surface application

4. Nerve block

5. Spinal anesthesia

Front 58

This is indicated for treatment that requires considerable volume of drug or necessitates a relatively long operation.

Back 58

Lidocaine with epinephrine

Front 59

Used when a truly extended effect of nerve block is desired.

Back 59

Bupivacaine with epinephrine