Deck 10: Local Anesthetics

Question 1

Chris is brought into the ER with cuts and bruises on his right leg.Among the following drugs,identify the drug that is most likely to be used to provide a long duration of anesthetic action.

A) Dibucaine
B) Procaine
C) Cocaine
D) Cyclomethycaine

Answer 1

Dibucaine

Question 2

The use of potent local anesthetics in toxic doses can lead to adverse effects in the central nervous system.These effects include nervousness,excitation,tremors,and convulsions.Which of the following is the most likely reason for these effects?

A) Depression of the activity of the cerebral cortex
B) Hypersensitivity to the local anesthetics
C) Stimulation of the cerebral cortex
D) None of the above

Answer 2

Stimulation of the cerebral cortex

Question 3

Identify the most commonly used local anesthetic technique.

A) Regional nerve block
B) Infiltration anesthesia
C) Topical application
D) Cryoanesthesia

Answer 3

Infiltration anesthesia

Question 4

Identify the most common clinical use of local anesthetics.

A) Abolition of painful stimulation prior to surgical procedures
B) Abolition of painful stimulation prior to dental procedures
C) Abolition of painful stimulation prior to obstetric procedures
D) All of the above

Question 5

Identify the type of impulse that sensory nerves carry to the brain.

A) Heat and cold
B) Pain
C) Touch
D) All of the above

Question 6

Which of the following medications is used to relieve the pain of postherpetic neuralgia?

A) Lidoderm 5% transdermal patch
B) Ethyl chloride topical spray
C) Menthol topical spray
D) None of the above

Question 7

Which of the following are the two anesthetics used in the preparation of EMLA?

A) Lidocaine and epinephrine
B) Procaine and lidocaine
C) Lidocaine and prilocaine
D) None of the above

Question 8

A practitioner has to perform a surgical procedure that requires the administration of a local anesthetic to the patient.The surgical procedure is to be performed on the right leg of the patient.The practitioner is unlikely to prescribe cocaine as the anesthetic because:

A) cocaine is classified as a Schedule II stimulant drug.
B) cocaine is obtained from a plant in South and Central America.
C) cocaine is a naturally occurring drug.
D) cocaine is a synthetically produced drug.

Question 9

Identify the drugs that fall into the category of amide local anesthetics.

A) Procaine, benzocaine, and tetracaine
B) Lidocaine, bupivacaine, and mepivacaine
C) Ethyl chloride, benzyl alcohol, and phenol
D) None of the above

Question 10

Cocaine cannot be administered by injection because:

A) injected cocaine produces vasodilation.
B) injected cocaine produces vasoconstriction.
C) injected cocaine relaxes the vascular smooth muscle.
D) injected cocaine produces hypotension.

Question 11

A patient is given local anesthetics before a minor surgical procedure.The effect of the local anesthetics does not wear off after the surgery and there is a loss of sensory perception and motor function.In such a case,which of the following is true of the anesthetic effect?

A) The anesthetized region will not to respond to hot or cold stimuli.
B) The patient should avoid eating or drinking for 1 hour if oral topical anesthetics were used.
C) The anesthetized region will not respond to scratching.
D) All of these are correct.

Question 12

Which of the following conditions is lidocaine,a local anesthetic,used to treat?

A) Allergic reactions
B) Hypotension
C) Cardiac arrhythmias
D) None of the above

Question 13

Which of the following is true of local anesthetics?

A) They block sensory nerves at doses that do not inhibit motor nerve function.
B) Their primary mechanism of action is the blockade of norepinephrine receptors.
C) They permeate skeletal muscle more easily than they do sensory and autonomic nerves.
D) Their primary mechanism of action involves the blockade of potassium ions.

Question 14

Why do local anesthetics that are given by injection occasionally contain epinephrine?

A) Epinephrine acts as a preservative in maintaining an extended shelf life.
B) Epinephrine counteracts the vasodilation that occurs with local anesthetic use.
C) Epinephrine counteracts the vasoconstriction that occurs with local anesthetic use.
D) None of the above are true.

Question 15

Why are local anesthetic preparations that contain epinephrine contraindicated for use in the areas of the fingers,toes,ears,nose,or penis?

A) The use of epinephrine in these areas may lead to ischemia and gangrene.
B) The use of epinephrine in these areas may lead to reflex sympathetic dystrophy.
C) The use of epinephrine in these areas may lead to peripheral vascular disease.
D) None of the above are true.

Question 16

Which of the following would be a key point in explaining to a patient why the practitioner is using cryoanesthesia for the removal of the patient's superficial lesions?

A) There is no need for an injection.
B) Cryoanesthesia has a short duration of action, so it will wear off in a short period of time.
C) The application is painless and requires spraying ethyl chloride for only 30 to 60 seconds.
D) All of the above are true.

Question 17

What is the mechanism of action of local anesthetics on the pain response?

A) Local anesthetics stimulate sensory nerves at low doses that increase the response of the motor nerves.
B) Local anesthetics block sensory nerves at low doses that do not inhibit motor nerve function.
C) Local anesthetics interact with nerve membranes to increase nerve conduction.
D) None of the above are correct.

Question 18

Which of the following forms the basis for the classification of peripheral nerve fibers and their neurons?

A) Diameter of the axon
B) Conduction velocity
C) Amount of myelin covering the nerve
D) All of the above

Question 19

An overdose of local anesthetics can lead to central nervous system (CNS)excitation.Which of the following should be used to reverse the effects of the overdose?

A) Barbiturates and diazepam (Valium)
B) Epinephrine and diazepam (Valium)
C) Barbiturates and epinephrine
D) None of the above

Question 20

What is the effect of local anesthetics on the heart?

A) Local anesthetics depress the function of the cardiac conduction system.
B) Local anesthetics produce tachycardia.
C) Local anesthetics cause hypertension.
D) Local anesthetics increase the function of the myocardium.

Question 21

When a patient has any form of liver disease that results in hepatic failure,which of the following may result from the administration of amide local anesthetics?

A) Rapid metabolism of the amide anesthetic agent
B) Accumulation of amide metabolites
C) Increased amide anesthetic clearance
D) None of the above

Question 22

A man is rushed to the ER with a deep wound on his left leg.A tourniquet is used to isolate his leg and an intravenous injection of a local anesthetic is administered to the leg before performing a short surgical procedure.This is referred to as a _____.

A) spinal blockade
B) caudal blockade
C) epidural blockade
D) Bier block

Question 23

Select the group that has the local anesthetics listed in order of increasing duration of action.

A) Geritrex, Lidoderm, Opthetic
B) Lidoderm, Opthetic, Geritrex
C) Opthetic, Geritrex, Lidoderm
D) None of the above

Question 24

How does the onset of action of ester local anesthetics differ from that of amide local anesthetics?

A) Ester local anesthetics have a shorter duration of action than amide local anesthetics.
B) Ester local anesthetics have a longer duration of action due to metabolism in the liver.
C) Ester local anesthetics have the same duration of action as amide local anesthetics.
D) None of the above are true.

Question 25

Which of the following could indicate central nervous system (CNS)toxicity?

A) Dizziness, blurred vision, and slurred speech
B) Nausea, vomiting, and diarrhea
C) Hyperactivity, hostility, and confusion
D) None of the above

Question 26

Ester local anesthetics have a short to moderate duration of action.Which of the following drugs fall into this category?

A) Procaine, benzocaine, and tetracaine
B) Lidocaine, bupivacaine, and mepivacaine
C) Ethyl chloride, GumEase, and EMLA cream
D) None of the above

Question 27

One of the differences between local and general anesthetics is that unlike local anesthetics,general anesthetics:

A) cause total loss of consciousness.
B) stimulate the activity of the central nervous system.
C) can limit the response to one area of the body.
D) None of the above are correct.

Question 28

Which of the following is an advantage of using cocaine in surgical procedures?

A) It causes significant hypotension.
B) It increases the dilation of blood vessels.
C) It decrease operative bleeding.
D) It relaxes vascular smooth muscle.

Question 29

Bupivacaine contains a black box warning against epidural use of 0.75% concentration during labor and delivery.Why is the 0.75% concentration of bupivacaine contraindicated for this use?

A) Cardiac arrest with difficult resuscitation may occur.
B) Convulsions may occur.
C) Ischemia and gangrene may occur.
D) None of the above are true.

Question 30

Local anesthetics eliminate the pain response by inhibiting the sensory nerves that carry painful stimuli to the central nervous system.Select a true statement about the mechanism of action of the local anesthetics.

A) Sodium ions are blocked from passing through the cell membrane.
B) Nerve depolarization is prevented.
C) Conduction of impulses along the nerves is blocked.
D) All of the above are true.

Question 31

The topical anesthetic procaine has been shown to inhibit the action of sulfonamide antibiotics.Why does this inhibition of action occur?

A) Procaine is metabolized to p-aminobenzoic acid, which competes with the sulfonamides for the bacterial site of action.
B) Procaine is metabolized to p-aminobenzoic acid, which has an additive effect with the sulfonamides on the bacterial site of action.
C) Procaine is metabolized to p-aminobenzoic acid, which increases the patient's sensitivity to sulfonamides.
D) None of the above are true.

Question 32

A patient comes in with a complaint of pruritus and facial swelling.He states that he has been using all of his usual medications and has also been using using an ester local anesthetic on a regular basis for the past 2 to 3 weeks for insect bites.What is the most likely cause of his symptoms?

A) Hypersensitivity reaction to para-amino benzoic acid
B) Severe drug-induced vasoconstriction
C) Hypersensitivity reaction to epinephrine
D) None of the above

Question 33

Why should one avoid applying local anesthetic agents to damaged,open,or broken skin?

A) The broken skin allows the anesthetic agent to reach the blood vessels.
B) The patient may develop overdose effects.
C) The patient may develop hypotension.
D) All of the above are true

Question 34

Injectable bupivacaine is available as a 0.25% to 0.75% solution with a duration of action of 2 to 4 hours and injectable procaine is available as a 1% to 2% solution with a duration of action of 15 minutes to 1 hour.Which of the following usually determines the choice of agent used for injection around the spinal cord?

A) Onset of action required
B) Concentration of the product
C) Duration of action required
D) None of the above

Question 35

In the context of local anesthetics,which of the following statements best explains potency?

A) Potency is the ability to increase velocity of nerve conduction.
B) Potency is the ability to produce a nerve block at a relatively low dose.
C) Potency is the ability to produce a heightened conduction of nerve impulses.
D) None of the above are correct.