KATZUNG'S BASIC AND
CLINICAL PHARMACOLOGY
16TH EDITION
• AUTHOR(S)TODD W.
VANDERAH
TEST BANK
,Question 1
A nurse is reviewing why a newly prescribed medication is
considered “selective” for a receptor. Which statement best
describes drug selectivity?
A. The drug binds only one receptor type in all tissues and has
no adverse effects
B. The drug has a greater affinity for certain receptors than for
others at usual therapeutic doses
C. The drug produces the same intensity of effect in every
patient regardless of dose
D. The drug can activate any receptor if the dose is increased
high enough
Correct Answer: B
Rationale:
Selectivity refers to a drug’s tendency to preferentially bind or
affect one receptor, tissue, or physiologic pathway more than
others at typical therapeutic concentrations. A selective drug is
not absolutely specific; as doses increase, selectivity may
diminish and off-target effects may occur. Option A is incorrect
because no drug is completely free of adverse effects and few
are absolutely specific to only one receptor in all tissues. Option
C is incorrect because response varies among patients based on
age, organ function, genetics, and other factors. Option D is
incorrect because while higher doses may increase off-target
,effects, this statement does not define selectivity and is overly
broad.
Question 2
A patient asks why one drug can cause a stronger effect than
another drug even when both act at the same receptor. Which
concept should the nurse use to explain this difference?
A. Potency only
B. Efficacy only
C. First-pass metabolism only
D. Bioavailability only
Correct Answer: B
Rationale:
Efficacy refers to the maximal effect a drug can produce once it
binds to the receptor and activates the physiologic response.
Two drugs can act at the same receptor but differ in efficacy if
one produces a greater maximal therapeutic response. Potency
refers to how much drug is needed to produce a given effect,
not the maximum effect achievable. First-pass metabolism and
bioavailability affect how much drug reaches systemic
circulation, but they do not directly explain why one drug has a
greater maximal effect at the receptor level.
Question 3
, A nurse administers a medication that occupies a receptor but
does not activate it and prevents the endogenous ligand from
producing a response. How should this drug action be
classified?
A. Full agonist
B. Partial agonist
C. Competitive antagonist
D. Enzyme inducer
Correct Answer: C
Rationale:
A competitive antagonist binds to a receptor without activating
it and blocks the endogenous ligand or agonist from binding,
thereby preventing receptor activation. A full agonist binds and
fully activates the receptor to produce a maximal response. A
partial agonist activates the receptor but produces a lower
maximal response than a full agonist even when all receptors
are occupied. Enzyme induction refers to increased metabolic
enzyme activity and is unrelated to receptor blockade in this
scenario.
Question 4
A nurse is teaching a patient about the therapeutic index of a
medication. Which explanation by the nurse is most accurate?
CLINICAL PHARMACOLOGY
16TH EDITION
• AUTHOR(S)TODD W.
VANDERAH
TEST BANK
,Question 1
A nurse is reviewing why a newly prescribed medication is
considered “selective” for a receptor. Which statement best
describes drug selectivity?
A. The drug binds only one receptor type in all tissues and has
no adverse effects
B. The drug has a greater affinity for certain receptors than for
others at usual therapeutic doses
C. The drug produces the same intensity of effect in every
patient regardless of dose
D. The drug can activate any receptor if the dose is increased
high enough
Correct Answer: B
Rationale:
Selectivity refers to a drug’s tendency to preferentially bind or
affect one receptor, tissue, or physiologic pathway more than
others at typical therapeutic concentrations. A selective drug is
not absolutely specific; as doses increase, selectivity may
diminish and off-target effects may occur. Option A is incorrect
because no drug is completely free of adverse effects and few
are absolutely specific to only one receptor in all tissues. Option
C is incorrect because response varies among patients based on
age, organ function, genetics, and other factors. Option D is
incorrect because while higher doses may increase off-target
,effects, this statement does not define selectivity and is overly
broad.
Question 2
A patient asks why one drug can cause a stronger effect than
another drug even when both act at the same receptor. Which
concept should the nurse use to explain this difference?
A. Potency only
B. Efficacy only
C. First-pass metabolism only
D. Bioavailability only
Correct Answer: B
Rationale:
Efficacy refers to the maximal effect a drug can produce once it
binds to the receptor and activates the physiologic response.
Two drugs can act at the same receptor but differ in efficacy if
one produces a greater maximal therapeutic response. Potency
refers to how much drug is needed to produce a given effect,
not the maximum effect achievable. First-pass metabolism and
bioavailability affect how much drug reaches systemic
circulation, but they do not directly explain why one drug has a
greater maximal effect at the receptor level.
Question 3
, A nurse administers a medication that occupies a receptor but
does not activate it and prevents the endogenous ligand from
producing a response. How should this drug action be
classified?
A. Full agonist
B. Partial agonist
C. Competitive antagonist
D. Enzyme inducer
Correct Answer: C
Rationale:
A competitive antagonist binds to a receptor without activating
it and blocks the endogenous ligand or agonist from binding,
thereby preventing receptor activation. A full agonist binds and
fully activates the receptor to produce a maximal response. A
partial agonist activates the receptor but produces a lower
maximal response than a full agonist even when all receptors
are occupied. Enzyme induction refers to increased metabolic
enzyme activity and is unrelated to receptor blockade in this
scenario.
Question 4
A nurse is teaching a patient about the therapeutic index of a
medication. Which explanation by the nurse is most accurate?
