Local Anesthetics

Question 1

single most important determining factor in efficacy of local anesthetics

Answer 1

Hydrophobicity – moderate is ideal

Question 2

class of drugs metabolized in the plasma and tissues by pseudocholinesterases.

Answer 2

Aminoesters

Question 3

class of drugs metabolized in the liver, lungs and kidneys

Answer 3

aminoamides

Question 4

stabilize the inactive conformation and increase the refractory period.

Answer 4

local anesthetics – Na channel blockade

Question 5

fixed ratio of Na channels are blocked at all times. Minimizes blockade of non-pain sensory modalities

Answer 5

Tonic inhibition

Question 6

Tissues undergoing high frequency stimulation. Degree of inhibition increases with the rate of action potential firing.

Answer 6

phasic inhibition

Question 7

Diffusion through which neurium is most difficult?

Answer 7

perineurium

Question 8

least sensitive fibers

Answer 8

muscle

Question 9

proximal numbing prior to distal

Answer 9

differential blockade

Question 10

applied prior to suturing small wounds

Answer 10

TAC – tetracaine, epinephrine, cocaine

Question 11

dental topical anesthetics

Answer 11

Lidocaine and benzocaine

Question 12

Dental injected anesthetics

Answer 12

lidocaine, mepivacaine, bupivacaine

Question 13

Dental ideal for pediatrics

Answer 13

Mepivacaine

Question 14

Dental more potent and longer T1/2 than mepivacaine or lidocaine. Lengthy proceedures and post op. Aminoamide

Answer 14

Bupivacaine

Question 15

epidural and intrathecal (spinal) anesthesia

Answer 15

central nerve block

Question 16

may be used to lengthen effect of peripheral nerve block, but caution not to cause hypoxia.

Answer 16

epinephrine

Question 17

great for epidural but may cause cardiotoxicity

Answer 17

Bupivacaine (Levobupivacaine and ropivacaine may be safer)

Question 18

proceedure where short acting LA is preferred (lidocaine). Uses tourniquet and distal band on an elevated extremety. No blood, practical time limit, BZ may be coadministered.

Answer 18

Intraveinous regional anesthesia

Question 19

short acting aminoester – low hydrophobicity. Infiltration anesthesia and dental, or OB

Answer 19

Procaine or 2-Chloroprocaine (OB)

Question 20

produces PABA metabolite that can act as an allergen and interfere with sulfonamide drugs.

Answer 20

Procaine

Question 21

amino ester with high hydrophobicity – long acting. Spinal and topical anesthesia

Answer 21

Tetracaine

Question 22

Medium potency and duration. Profound cardiotoxic potential. Ophthalmic anesthesia and part of TAC.

Answer 22

Cocaine

Question 23

Most commonly used local anesthetic. Used for everything. AE – drowsiness, tinnitis, twitching, and seizures

Answer 23

Lidocaine

Question 24

similar to lidocaine, but exibits vasoconstriction. Good for pt in which epinephrine in contraindicated.

Answer 24

Prilocaine

Question 25

aminoamide with an ester bond – metabolized in both plasma and liver

Answer 25

Articaine

Question 26

combination of lidocaine and prilocaine – cream or patch, useful in dental (children), venipuncture, lumbar puncture, arterial cannulation. Cocaine induced euphoria

Answer 26

EMLA

Question 27

Local irritation – skeletal muscle, smooth muscle – biphasic vessels and bronchiols, cardiac tissue – decrease conduction velocities and contractility, CNS – cross BBB initially inducing excitement followed by depression, Immune system – hypersensitive dermatitis and asthma (aminoesters)

Answer 27

major toxicities