C H A P T E R 3

Pharmacology of Vasoconstrictors

Multiple Choice
1. Vasodilation from injected local anesthetics leads to
a. increased bleeding at the site of treatment.
b. increased depth and duration of anesthesia.
c. decreased plasma levels of the local anesthetic.
d. decreased anesthetic absorption and redistribution.

2. Which local anesthetic ingredient acts as a vasoconstrictor?

a. Epinephrine.
b. Lidocaine HCl.
c. Methylparaben.
d. Sodium (meta)bisulfite.

3. Vasoconstrictors control tissue perfusion by which process?

a. Decreasing cardiac output.
b. Constricting blood vessels.
c. Increasing the clotting ability of the blood.
d. Disrupting calcium movement into blood vessel cells.

4. Vasoconstrictors are added to local anesthetic solutions to

a. counteract the intrinsic vasodilation.
b. reduce the possibility of vasculitis.
c. boost an inherent vasoconstriction.
d. prevent blood vessel wall collapse.

5. The effect of local anesthesia is prolonged with the addition of a vasoconstrictor because
a. the risk of local anesthetic toxicity is reduced.
b. bleeding is decreased at the site of administration.
c. the local anesthetic slowly enters the circulatory system.
d. more local anesthetic enters and inhabits the nerve for a longer duration.

6. Which catecholamine is synthetic?

a. Dopamine.
b. Epinephrine.
c. Levonordefrin.
d. Norepinephrine.

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3—PHARMACOLOGY OF VASOCONSTRICTORS 21

7. Beta receptors produce each of the following EXCEPT one. Which is the EXCEPTION?
a. Vasodilation.
b. Vasoconstriction.
c. Increased heart rate.
d. Stronger cardiac contractions.

8. Which best defines tachyphylaxis?

a. Cardiac palpitations and accelerated heart rate.
b. Genetic disorder that alters the ordinary drug response.
c. Pharmacologic effect that mimics the response of adrenergic nerves.
d. Declining effectiveness of a drug which has been administered repeatedly.

9. How many grams of epinephrine are contained in a solution with a 1 : 1000 dilution?
a. 1
b. 0.1
c. 0.01
d. 0.001

10. Which statement is true?

a. Epinephrine is the most widely used vasoconstrictor in dentistry.
b. Epinephrine is an ideal drug for medical and dental local anesthetics.
c. A 1 : 10,000 epinephrine ratio is the most common dilution used in dentistry.
d. Intraoral administration of epinephrine does not affect the cardiovascular system.

11. Which sign or symptom is NOT anticipated with an epinephrine reaction?

a. Sweating.
b. Palpitations.
c. Bradycardia.
d. Apprehension.

12. Norepinephrine elicits side effects

a. three times less often than epinephrine.
b. five times more often than epinephrine.
c. seven times less often than epinephrine.
d. nine times more often than epinephrine.

13. Which additive is commonly used to delay the oxidation of epinephrine?

a. Distilled water.
b. Methylparaben.
c. Sodium chloride.
d. Sodium bisulfite.

14. A local anesthetic that contains epinephrine has

a. a longer shelf life than one that does not contain epinephrine.
b. a shorter shelf life than one that does not contain epinephrine.
c. an equivalent shelf life to one that does not contain epinephrine.
d. no shelf life, and must be used immediately for clinical efficacy.
22 3—PHARMACOLOGY OF VASOCONSTRICTORS

15. Epinephrine decreases which cardiovascular dynamic?

a. Heart rate.
b. Stroke volume.
c. Cardiac efficiency.
d. Systolic blood pressure.

16. Which adrenergic receptor dominates the mucous membrane blood vessels?
a. Alpha (α).
b. Beta 1 (β1).
c. Beta 2 (β2).
d. Beta 3 (β3).

17. When epinephrine is used in dental surgery, postsurgical bleeding usually occurs after
a. 1 hour.
b. 3 hours.
c. 6 hours.
d. 12 hours.

18. Which describes the principal way epinephrine is eliminated from the system?
a. Excreted in the urine.
b. Reabsorbed by adrenergic nerves.
c. Inactivated by monoamine oxidase (MAO).
d. Inactivated by catechol-O-methyltransferase (COMT).

19. The maximum dose of epinephrine (1 : 100,000) for a normal healthy patient is
a. 1 cartridge.
b. 2 cartridges.
c. 5.5 cartridges.
d. 11 cartridges.

20. Compared with epinephrine, norepinephrine is

a. one half as potent.
b. one fourth as potent.
c. two times more potent.
d. three times more potent.

21. Levonordefrin is available in which dental anesthetic?

a. Articaine.
b. Lidocaine.
c. Mepivacaine.
d. Bupivacaine.

22. Which vasoconstrictor is the weakest?

a. Epinephrine.
b. Levonordefrin.
c. Phenylephrine.
d. Norepinephrine.
3—PHARMACOLOGY OF VASOCONSTRICTORS 23

23. Which statement is correct?

a. Felypressin is contraindicated for hyperthyroid patients.
b. Felypressin directly stimulates vascular smooth muscle.
c. Felypressin is a naturally produced antidiuretic hormone.
d. Felypressin has a positive inotropic action on the myocardium.

24. Which occurs when a vasoconstrictor is added to most local anesthetics?

a. The depth of hard tissue anesthesia is reduced.
b. The duration of pulpal anesthesia is prolonged.
c. The duration of soft tissue anesthesia is shortened.
d. The depth and duration of hard and soft tissue anesthesia are unaffected.

25. Which vasoconstrictor is used routinely for dental surgery hemostasis?

a. Felypressin.
b. Epinephrine.
c. Phenylephrine.
d. Norepinephrine.

Feedback
1. ANS: a
a. Correct. Vasodilation following the injection of local anesthetics leads to increased bleed-
ing at the treatment site.
b. The depth and duration of anesthesia is decreased, not increased, as a result of
vasodilation.
c. Plasma levels of the local anesthetic increase, rather than decrease, as a result of
vasodilation.
d. The rate of anesthetic absorption and redistribution increases, rather than decreases, as
a result of vasodilation.

REF: p. 39

2. ANS: a
a. Correct. Epinephrine is a common vasoconstrictor added to local anesthetics.
b. Lidocaine HCl is a local anesthetic drug that blocks nerve conduction.
c. Methylparaben is a bacteriostatic agent found in local anesthetic solutions.
d. Sodium (meta)bisulfite is an antioxidant found in local anesthetic solutions.

REF: pp. 39, 40, 103

3. ANS: b
a. Vasoconstrictors constrict blood vessels, rather than decrease cardiac output, to control
tissue perfusion.
b. Correct. Vasoconstrictors decrease tissue perfusion, or blood flow, by constricting blood
vessels.
c. Vasoconstrictors do not increase blood coagulation, but instead constrict blood vessels to
control tissue perfusion.
d. Vasoconstrictors act on the blood vessel walls, not calcium channels, to control tissue
perfusion.

REF: p. 39
24 3—PHARMACOLOGY OF VASOCONSTRICTORS

4. ANS: a
a. Correct. Injectable local anesthetics are vasodilators, so vasoconstrictors are added to
solution to counteract this intrinsic vasodilation.
b. Vasoconstrictors are added to local anesthetic solutions to counteract intrinsic vasodila-
tion, not reduce vasculitis.
c. Vasoconstrictors are added to local anesthetic solutions to counteract intrinsic vasodila-
tion, not boost inherent vasoconstriction.
d. Vasoconstrictors are added to local anesthetic solutions to counteract intrinsic vasodila-
tion, not prevent vessel wall collapse.

REF: p. 39

5. ANS: d
a. The risk of toxicity is reduced by the addition of a vasoconstrictor; however, the reason
anesthesia exhibits an increased duration is because more anesthetic enters and inhabits
the nerve for a longer period of time.
b. Bleeding at the site of administration is decreased with the addition of a vasoconstrictor;
however, the reason anesthesia exhibits an increased duration is because more anesthetic
enters and inhabits the nerve for a longer period of time.
c. Prolonged anesthesia results when more anesthetic enters and inhabits the nerve for a
longer period of time; slow uptake into the cardiovascular system results in lower anes-
thetic blood levels.
d. Correct. The duration of anesthesia is increased with the addition of a vasoconstrictor
because more local anesthetic enters the nerve, where it stays for a longer period of time.

REF: p. 39

6. ANS: c
a. Dopamine is produced naturally in the sympathetic nervous system.
b. The sympathetic nervous system produces epinephrine naturally.
c. Correct. Levonordefrin is a synthetic catecholamine.
d. Norepinephrine is a natural product of the sympathetic nervous system.

REF: p. 39

7. ANS: b
a. Vasodilation occurs when β2 receptors are activated.
b. Correct. Vasoconstriction occurs when α, not β, receptors are stimulated.
c. Activated β2 receptors produce increased heart rate.
d. Stronger cardiac contractions result when β2 receptors are activated.

REF: p. 40

8. ANS: d
a. The epinephrine reaction causes cardiac palpitations and tachycardia.
b. Malignant hyperthermia is a genetic disorder that alters the ordinary drug response.
c. Sympathomimetic drugs mimic the response of adrenergic nerves.
d. Correct. Tachyphylaxis is the declining effectiveness of a pharmaceutical with each
administration.

REF: p. 40
3—PHARMACOLOGY OF VASOCONSTRICTORS 25

9. ANS: a
a. Correct. In a concentration of 1 : 1000, there is 1 g of epinephrine for every 1000 mL
of solution.
b. There is 0.1 g of epinephrine in a concentration of 1 : 10,000.
c. There is 0.01 g of epinephrine in a dilution of 1 : 100,000.
d. There is 0.001 g of epinephrine in a dilution of 1 : 1,000,000.

REF: p. 41

10. ANS: a
a. Correct. The most widely used vasoconstrictor in dental anesthetics is epinephrine.
b. Epinephrine is not an ideal drug; risks and benefits must be examined before
administration.
c. The most common epinephrine concentration is 1 : 200,000 for dental anesthetics.
d. The intraoral administration of epinephrine is associated with moderate cardiac output
and stroke volume.

REF: pp. 41–42

11. ANS: c
a. Sweating is a common sign of an epinephrine reaction.
b. Cardiac palpitations are a common symptom of an epinephrine reaction.
c. Correct. Tachycardia, not bradycardia, occurs when a patient experiences an epinephrine
reaction.
d. Apprehension is a common symptom of an epinephrine reaction.

REF: p. 42

12. ANS: d
a. Norepinephrine elicits side effects nine times more often than epinephrine.
b. Side effects are nine times more likely to occur with norepinephrine than with
epinephrine.
c. Side effects are nine times less likely to occur with epinephrine than with
norepinephrine.
d. Correct. The likelihood that a patient will experience side effects is nine times greater
with the administration of norepinephrine than with epinephrine.

REF: p. 42

13. ANS: d
a. Distilled water is added to the anesthetic solution to dilute the solute (drug).
b. Methylparaben was once added as a bacteriostatic, but is no longer included in local
anesthetic cartridges.
c. Sodium chloride makes the anesthetic solution isotonic with surrounding tissues.
d. Correct. Sodium bisulfite is used to postpone the oxidation of solutions that contain
epinephrine.

REF: p. 42
26 3—PHARMACOLOGY OF VASOCONSTRICTORS

14. ANS: b
a. Epinephrine shortens, rather than lengthens, the shelf life of a local anesthetic.
b. Correct. A local anesthetic that contains epinephrine has a shorter shelf life than one
that does not.
c. Epinephrine truncates the shelf life of a local anesthetic solution.
d. Although the shelf life of a local anesthetic is shortened by the addition of epinephrine,
it remains intact until about 18 months.

REF: p. 42

15. ANS: c
a. Epinephrine stimulates β receptors in the myocardium to increase the heart rate.
b. Epinephrine creates a positive inotropic effect on the myocardium, resulting in increased
stroke volume.
c. Correct. The overall effect of epinephrine on the cardiovascular system leads to a decrease
in cardiac efficiency.
d. Epinephrine elicits an increase in systolic blood pressure.

REF: p. 43

16. ANS: a
a. Correct. The blood vessels that supply the mucous membranes of the oral cavity mainly
contain α receptors.
b. α, not β1, receptors are found in the blood vessels of the oral mucous membranes.
c. α, not β2, receptors are found in the blood vessels of the oral mucous membranes.
d. α, not β3, receptors are found in the blood vessels of the oral mucous membranes.

REF: p. 43

17. ANS: c
a. Postsurgical bleeding usually occurs 6 hours, not 1, after the administration of
epinephrine.
b. Postsurgical bleeding usually occurs 6, not 3, hours after the administration of
epinephrine.
c. Correct. When epinephrine is administered with the anesthetic for hemostasis, postsur-
gical bleeding usually occurs 6 hours after the surgery.
d. Postsurgical bleeding usually occurs 6, not 12, hours after the administration of
epinephrine.

REF: p. 43

18. ANS: b
a. Only 1% of epinephrine is excreted, unchanged, in the urine.
b. Correct. Epinephrine’s action is principally terminated through its reuptake by adrener-
gic nerves.
c. Adrenergic nerves reabsorb most of the epinephrine; MAO inactivates the epinephrine
that escapes in the blood.
d. Adrenergic nerves reabsorb most of the epinephrine; COMT inactivates the epinephrine
that escapes in the blood.

REF: p. 43
3—PHARMACOLOGY OF VASOCONSTRICTORS 27

19. ANS: d
a. The maximum epinephrine dosage for a patient with significant cardiovascular disease is
1 anesthetic cartridge, if the concentration is 1 : 50,000.
b. The maximum epinephrine dosage (1 : 100,000) for a patient with significant cardiovas-
cular disease is 2 anesthetic cartridges.
c. The maximum epinephrine dosage for a normal, healthy patient is 5.5 anesthetic car-
tridges, if the concentration is 1 : 50,000.
d. Correct. The maximum epinephrine dosage (1 : 100,000) for a normal, healthy patient
is 11 anesthetic cartridges.

REF: p. 44

20. ANS: b
a. Norepinephrine is four times less potent than epinephrine.
b. Correct. Compared with epinephrine, norepinephrine is one fourth as potent.
c. Norepinephrine is less, not more, potent than epinephrine.
d. Norepinephrine is less, not more, potent than epinephrine.

REF: p. 45

21. ANS: c
a. In dental anesthetics, levonordefrin is available in mepivacaine; the vasoconstrictor avail-
able with articaine is epinephrine.
b. Levonordefrin, in dental anesthetics, is available in mepivacaine; the vasoconstrictor with
lidocaine is epinephrine.
c. Correct. Levonordefrin is available in mepivacaine in a 1 : 20,000 concentration.
d. Levonordefrin is available in mepivacaine dental cartridges; the vasoconstrictor paired
with bupivacaine is epinephrine.

REF: p. 47

22. ANS: c
a. Phenylephrine is the weakest vasoconstrictor ever used in dentistry; epinephrine is the
most potent.
b. Levonordefrin is a stronger vasoconstrictor than phenylephrine.
c. Correct. Phenylephrine is a weaker vasoconstrictor than epinephrine, levonordefrin, or
norepinephrine.
d. Norepinephrine is a stronger vasoconstrictor than phenylephrine.

REF: p. 47

23. ANS: b
a. Felypressin is safe and well tolerated by individuals with hyperthyroidism.
b. Correct. Felypressin stimulates vascular smooth muscle.
c. Felypressin is a synthetic analog of vasopressin.
d. Felypressin has no direct effect on the myocardium.

REF: p. 48
28 3—PHARMACOLOGY OF VASOCONSTRICTORS

24. ANS: b
a. The depth of hard tissue anesthesia is increased with the inclusion of a vasoconstrictor.
b. Correct. Pulpal anesthesia is prolonged with the inclusion of a vasoconstrictor.
c. The duration of soft tissue anesthesia is lengthened, not shortened, by the addition of a
vasoconstrictor to the anesthetic solution.
d. With the inclusion of a vasoconstrictor, the depth of hard and soft tissue anesthesia
increases, and anesthetic duration is prolonged.

REF: p. 48

25. ANS: b
a. Felypressin provides very little hemostasis.
b. Correct. Epinephrine is routinely used for dental surgery hemostasis.
c. Phenylephrine is not available in dental anesthetic solutions.
d. Norepinephrine is not recommended as a dental vasoconstrictor.

REF: p. 49