Applied Pharmacology for the Dental Hygienist 8th Edition Haveles Test Bank
Chapter 02: Drug Action and Handling
Haveles: Applied Pharmacology for the Dental Hygienist, 8th Edition
MULTIPLE CHOICE
1. A drug is defined as a biologically active substance that can modify
a. the environment.
b. the pH of tissue.
c. cellular function.
d. immune response.
ANS: C
A drug can modify cellular function. A general understanding of drug action allows the dental
hygienist to make informed decisions regarding possible drug interactions or adverse reactions
for the patient. It is a concern that discarded drugs may be affecting the environment, but this
is not the definition of a drug. Some drugs may have the capacity to modify body
compartment pH; however, this is not the definition for a drug. Some drugs may have the
capacity to modify the immune response, but this is not the definition of a drug.
DIF: Recall REF: Introduction | p. 11 OBJ: 1
TOP: NBDHE, 6.0. Pharmacology
2. In comparing two drugs, the dose-response curve for the drug that is more efficacious would
a. be closer to the y-axis.
b. be farther from the y-axis.
c. have a greater curve height.
N RS N T
d. have a higher median effecU tive dose (ED50).
ANS: C
Efficacy is an expression of maximum intensity of effect or response that can be produced by
a drug. The other choices refer to indicators of drug potency, not efficacy. The potency of a
drug is a function of the amount of drug required to produce an effect. The potency of drug is
shown by the location of that drug’s curve along the log-dose axis (x-axis).
DIF: Comprehension REF: Characterization of Drug Action (Efficacy) | p. 11
OBJ: 1 TOP: NBDHE, 6.0. Pharmacology
3. Administering a drug of greater potency is better because drugs of greater potency do not
require as high a dose.
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.
ANS: D
, Applied Pharmacology for the Dental Hygienist 8th Edition Haveles Test Bank
The first part of the statement is false, the second part is true. The absolute potency of a drug
is immaterial as long as the appropriate dose is administered. If equally efficacious, both
drugs will produce the same effect. Both meperidine and morphine, for example, have the
ability to treat severe pain, but approximately 100 mg of meperidine would be required to
produce the same action as 10 mg of morphine. The dose of meperidine needed to produce
pain relief is larger than that for morphine. Less potent drugs require higher doses to produce
therapeutic effects whereas more potent drugs can reach toxic levels at lower doses.
DIF: Application REF: Characterization of Drug Action (Potency) | p. 11
OBJ: 1 TOP: NBDHE, 6.0. Pharmacology
4. Which of the following statements is true regarding the therapeutic index (TI) of a drug?
a. A drug with a large TI is more dangerous than a drug with a small TI.
b. The formula for TI is ED50/LD50.
c. ED50 is 50% of the effective clinical dose.
d. TI is the ratio of the median lethal dose to the median effective dose.
ANS: D
LD50 is the dose causing death in 50% of test animals and ED50 is the dose required to
produce the desired clinical effect in 50% of test animals. The greater the TI, the safer the
drug. The formula is TI = LD50/ED50. The ED50 is the dose required to produce the desired
clinical effect in 50% of test animals, not 50% of the effective clinical dose.
DIF: Comprehension
REF: Characterization of Drug Action (Therapeutic Index) | p. 12
OBJ: 1 TOP: NBDHE, 6.0. Pharmacology
5. Which of the following statement is true concerning the mechanism of action of drugs?
a. Drugs are capable of imparting a new function to the organism.
b. Drugs either produce the same action as an exogenous agent or block the action of
an exogenous agent.
c. Drugs either produce the same action as an exogenous agent or block the action of
an endogenous agent.
d. Drugs either produce the same action as an endogenous agent or block the action
of an endogenous agent.
ANS: D
Drugs either produce the same action as an endogenous agent or block the action of an
endogenous agent. Drugs do not impart a new function to the organism; they merely either
produce the same action as an endogenous agent or block the action of an endogenous agent.
DIF: Comprehension REF: Mechanism of Action of Drugs | p. 12 & 13
OBJ: 2 TOP: NBDHE, 6.0. Pharmacology
6. When different drugs compete for the same receptor sites, the drug with the stronger affinity
for the receptor will bind to
a. more receptors than the drug with the weaker affinity.
b. fewer receptors than the drug with the weaker affinity.
c. all of the available receptors.
d. none of the available receptors.
ANS: A
, Applied Pharmacology for the Dental Hygienist 8th Edition Haveles Test Bank
When different drugs compete for the same receptor sites, the drug with the stronger affinity
for the receptor will bind to more receptors than the drug with the weaker affinity. More of the
drug with weaker affinity will be required to produce a pharmacologic response. Drugs with a
stronger affinity for receptor sites are more potent than drugs with weaker affinities for the
same site.
DIF: Recall REF: Mechanism of Action of Drugs (Receptors) | p. 13
OBJ: 2 TOP: NBDHE, 6.0. Pharmacology
7. When a drug has affinity for a receptor and produces no effect, it is called a(n)
a. agonist.
b. competitive antagonist.
c. competitive agonist.
d. physiologic agonist.
ANS: B
A competitive antagonist has affinity for a receptor, combines with the receptor, competes
with the agonist for the receptor, and produces no effect. An agonist has affinity for a
receptor, combines with the receptor, and produces an effect. Competitive agonist is
nonsensical terminology. A physiologic antagonist has affinity for a site different from that of
the agonist in question.
DIF: Recall
REF: Mechanism of Action of Drugs (Receptors [Agonists and Antagonists]) | p. 13
OBJ: 2 TOP: NBDHE, 6.0. Pharmacology
8. A noncompetitive antagonist
a. binds to the same receptor site as the binding site for the agonist.
b. causes a shift to the right in the dose-response curve.
c. enhances the maximal response of the agonist.
d. reduces the maximal response of the agonist.
ANS: D
A noncompetitive antagonist reduces the maximal response of the agonist. Noncompetitive
antagonists bind to a receptor site that is different from the binding site for the agonist. A
competitive antagonist will cause a shift to the right in the dose-response curve.
DIF: Recall
REF: Mechanism of Action of Drugs (Receptors [Agonists and Antagonists]) | p. 13
OBJ: 2 TOP: NBDHE, 6.0. Pharmacology
9. Which of the following is not a subject of pharmacokinetics?
a. Physiologic action of drugs
b. Metabolism of drugs
c. Elimination of drugs
d. Absorption of drugs
ANS: A
The physiologic action of drugs is a subject of pharmacology, not pharmacokinetics.
Pharmacokinetics does have to do with the subjects of absorption, distribution, metabolism,
and excretion of drugs.
