Deck 9: Local Anesthetics

Question 1

In the presence of an acidic environment, such as infection or inflammation, the amount of free base is reduced; therefore _____ of the local anesthetic is in the ionized form, making anesthesia _____ difficult.

A) more; more
B) more; less
C) less; more
D) less; less

Answer 1

more; more

Question 2

Which of the following local anesthetics is safest to use for dental treatment for a pregnant woman?

A) Mepivacaine
B) Lidocaine
C) Articaine
D) Bupivacaine

Answer 2

Lidocaine

Question 3

Reducing the rate of systemic absorption of a local anesthetic is important when it is used in dentistry because:

A) otherwise, too large an area would be anesthetized.
B) if not, the anesthesia would not last long enough to complete a dental procedure.
C) the chance of systemic toxicity is reduced.
D) local anesthesia is associated with respiratory depression.

Answer 3

the chance of systemic toxicity is reduced.

Question 4

Which portion of the chemical structure of a typical local anesthetic is considered lipophilic (lipid soluble)?

A) Aromatic nucleus
B) Amino group
C) Both a and b
D) Neither a nor b

Question 5

The cationic form of a local anesthetic is needed to penetrate the nerve membrane, and the free base form exerts blocking action by binding to the specific receptor site.

A) Both parts of the statement are true.
B) Both parts of the statement are false.
C) The first part of the statement is true; the second part is false.
D) The first part of the statement is false; the second part is true.

Question 6

Epinephrine is combined with local anesthetics so as to:

A) enhance absorption.
B) prolong duration.
C) delay onset.
D) increase potency.

Question 7

The maximal safe dose of lidocaine 2% with 1:100,000 epinephrine is approximately _____ cartridges.

A) 3
B) 6.5
C) 8.5
D) 11.5

Question 8

Local anesthetics cross:

A) the placenta and blood-brain barrier.
B) the placenta but not the blood-brain barrier.
C) the blood-brain barrier but not the placenta.
D) neither the placenta nor the blood-brain barrier.

Question 9

The correct ADA color code for lidocaine 2% with epinephrine 1:100,000 is:

A) black.
B) green.
C) red.
D) gold.
E) brown.

Question 10

Repolarization of a nerve occurs by:

A) influx of potassium.
B) influx of sodium.
C) efflux of potassium.
D) efflux of calcium.
E) none of the above.

Question 11

Which nerve function is the most sensitive to inhibition by local anesthetic agents?

A) Touch
B) Warmth
C) Pressure
D) Autonomic
E) Pain

Question 12

Which of the following agents are the most likely to precipitate malignant hyperthermia: (1)halothane, (2)lidocaine, (3)mepivacaine, (4)succinylcholine?

A) 1, 2, 3, 4
B) 2, 3, 4
C) 2, 3
D) 1, 4

Question 13

Which of the following components of an injected amide local anesthetic agent may produce a hypersensitivity reaction that exhibits itself as an acute asthmatic attack?

A) The vasoconstrictor
B) The antioxidant for the vasoconstrictor
C) The sodium hydroxide
D) The sodium chloride

Question 14

The following states are characteristics of the salt form of a local anesthetic except which one?

A) Charged, cation (ionized)
B) Alkaline
C) Crystalline solid
D) Stable

Question 15

Addition of vasoconstrictor to local anesthetic (1)reduces blood supply to the area, (2)increases blood supply to the area, (3)limits systemic absorption, (4)increases systemic absorption, (5)reduces systemic toxicity, and (6)increases systemic toxicity.
Which of these are correct?

A) 1, 3, 5
B) 1, 4, 5
C) 2, 3, 5
D) 2, 3, 6
E) 2, 4, 6

Question 16

The mechanism of local anesthetics involves action on:

A) myelinated nerve.
B) axons.
C) sodium channels.
D) both a and c.
E) both b and c.

Question 17

Which of the following local anesthetic agents have the potential to cause methemoglobinemia as an adverse effect?

A) Prilocaine and lidocaine
B) Lidocaine and mepivacaine
C) Prilocaine and mepivacaine
D) Prilocaine and articaine
E) Mepivacaine and articaine

Question 18

All of the following are characteristics of the ideal local anesthetic except:

A) sterilization by autoclave.
B) slow onset.
C) reversible.
D) absence of local reactions.

Question 19

Amide local anesthetics are metabolized:

A) by being hydrolyzed by plasma pseudocholinesterases.
B) primarily by the liver.
C) in the spleen.
D) minimally and are excreted virtually unchanged.

Question 20

Procaine (Novocaine)is metabolized primarily by the:

A) liver.
B) lungs.
C) plasma.
D) kidneys.

Question 21

Which two agents are known to cause clinically significant drug interactions when combined with epinephrine?

A) Selective serotonin reuptake inhibitors and b-adrenergic antagonists
B) b-Adrenergic antagonists and phenothiazines
C) Tricyclic antidepressants and monoamine oxidase inhibitors
D) b-Adrenergic antagonists and tricyclic antidepressants
E) Benzodiazepines and monoamine oxidase inhibitors

Question 22

A cardiac patient can be given _____ cartridges of a dental anesthetic with epinephrine 1:100,000 without exceeding the cardiac dose for the vasoconstrictor.

A) 0.5
B) 2
C) 4
D) 6

Question 23

Which of the following local anesthetics has the longest duration of action?

A) Lidocaine
B) Mepivacaine
C) Prilocaine
D) Bupivacaine

Question 24

Which local anesthetic agent is neither an ester nor an amide?

A) Propoxycaine
B) Dyclonine
C) Articaine
D) Lidocaine

Question 25

Approximately _____% of articaine is metabolized by the liver.

A) 5 to 10
B) 20 to 25
C) 50 to 75
D) 90

Question 26

Plain anesthetics without vasoconstrictor will exhibit a _____ duration of action and result in a _____ rapid buildup of a systemic blood level.

A) shorter; less
B) shorter; more
C) longer; less
D) longer; more

Question 27

Lidocaine with epinephrine 1:100,000 provides a _____ duration of pulpal anesthesia.

A) 30-minute
B) 30- to 60-minute
C) 60- to 90-minute
D) 90-minute or more

Question 28

Levonordefrin is commonly combined with which local anesthetic?

A) Lidocaine
B) Procaine
C) Mepivacaine
D) Bupivacaine

Question 29

Prilocaine plain has a duration of action slightly _____ than mepivacaine plain, and prilocaine with epinephrine has a duration of action slightly _____ than lidocaine with epinephrine.

A) shorter; shorter
B) shorter; longer
C) longer; shorter
D) longer; longer

Question 30

Several cases of methemoglobinemia have been reported after the use of:

A) lidocaine.
B) mepivacaine.
C) prilocaine.
D) articaine.

Question 31

Which of the following dental local anesthetics is associated with an increased incidence of paresthesia following an inferior alveolar (IA)block?

A) Lidocaine 2% with epinephrine 1:100,000
B) Lidocaine 2% with epinephrine 1:50,000
C) Mepivacaine 2% with levonordefrin 1:20,000
D) Prilocaine 4% with epinephrine 1:200,000
E) Articaine 4% with epinephrine 1:100,000

Question 32

Which of the following statements is true of mepivacaine?

A) Cross-allergenicity has been demonstrated between mepivacaine and other currently available amides.
B) Mepivacaine is effective topically.
C) Mepivacaine can be used as a 3% solution without a vasoconstrictor.
D) The benefit of a shorter duration of anesthesia warrants eliminating the vasoconstrictor.

Question 33

The maximal safe dose of epinephrine for the cardiac patient is _____ mg.

A) 0.02
B) 0.04
C) 0.2
D) 0.4

Question 34

The vasoconstrictors are members of the autonomic nervous system drugs called the:

A) adrenergic agonists
B) adrenergic antagonists
C) cholinergic agonists
D) cholinergic antagonists

Question 35

Which of the following dental local anesthetic agents is available in a 1.7 ml dental cartridge unlike the more common 1.8 ml dental cartridge?

A) Lidocaine (Xylocaine, Octocaine)
B) Bupivacaine (Marcaine)
C) Mepivacaine (Carbocaine, Isocaine)
D) Prilocaine (Citanest)
E) Articaine (Septocaine)

Question 36

Which agent has the greater proportion of a-adrenergic activity to b-adrenergic activity?

A) Levonordefrin
B) Epinephrine
C) Neither-they have equivalent proportions.

Question 37

_____ is an ester local anesthetic.

A) Prilocaine (Citanest)
B) Tetracaine (Pontocaine)
C) Bupivacaine (Marcaine)
D) Lidocaine (Xylocaine)

Question 38

Patients with uncontrolled high blood pressure, hyperthyroidism, angina pectoris, and cardiac arrhythmias and those who have had a myocardial infarction or cerebrovascular accident in the past _____ should make an appointment for elective dental treatment only after their medical condition is under control.

A) 6 weeks
B) 3 months
C) 6 months
D) 12 months

Question 39

Which local anesthetic agent is derived from thiophene?

A) Tetracaine
B) Bupivacaine
C) Articaine
D) Propoxycaine

Question 40

Which of the following local anesthetic agents is both an ester and an amide?

A) Benzonatate
B) Articaine
C) Bupivacaine
D) Dyclonine

Question 41

No justification exists for the use of epinephrine in a concentration greater than 1:200,000, except in cases in which hemostasis is needed.

Question 42

Patients who are allergic to procaine are not likely to display cross-hypersensitivity to lidocaine.

Question 43

The rate of local anesthetic absorption is increased by the presence of local inflammation.

Question 44

A patient can produce endogenous epinephrine far in excess of that administered in dentistry in the presence of inadequate anesthesia.

Question 45

Which of the following agents is the most common topical local anesthetic?

A) Lidocaine
B) Benzocaine
C) Tetracaine
D) Dyclonine

Question 46

Which of the following local anesthetics may be combined for injection-free local anesthesia?

A) Articaine and bupivacaine
B) Lidocaine and prilocaine
C) Benzocaine and tetracaine
D) Lidocaine and articaine

Question 47

Levonordefrin is more potent than epinephrine.

Question 48

For lengthy dental procedures, bupivacaine is recommended over lidocaine because bupivacaine has a longer duration of action.

Question 49

The recommended concentration of epinephrine to combine with a local anesthetic is 1:200,000 for most procedures.

Question 50

Use of skin testing to determine local anesthetic allergies is not reliable.

Question 51

Which of the following dental local anesthetics are available without vasoconstrictor? (Select all that apply.)

A) Mepivacaine
B) Prilocaine
C) Articaine
D) Bupivacaine