NR 565 Final Study Guide | Practice Questions,
Answers & Complete Review
Section 1: Pharmacokinetics, Pharmacodynamics & Pharmacogenomics
Question 1
A nurse practitioner is reviewing factors that influence drug absorption. Which of the following
factors would most likely increase the rate of drug absorption?
A. Increased gastric emptying time
B. High lipid solubility of the drug
C. Large molecular size of the drug
D. Decreased surface area for absorption
Correct Answer: B
Rationale: Lipid-soluble drugs cross biological membranes more readily via passive
diffusion, which speeds absorption. Factors that affect absorption include rate of dissolution,
surface area, blood flow, lipid solubility, and pH partitioning . Increased gastric emptying time
would delay absorption, while large molecular size and decreased surface area would reduce it.
Question 2
Which statement best describes pharmacodynamics?
A. The study of how the body affects a drug
B. The study of what the drug does to the body
C. The process of drug excretion
D. The movement of drugs across membranes
Correct Answer: B
Rationale: Pharmacodynamics is defined as the study of the biochemical and physiologic
effects of drugs on the body and the molecular mechanisms by which those effects are
produced — essentially “what the drug does to the body” . Pharmacokinetics describes “what
the body does to the drug,” including absorption, distribution, metabolism, and excretion.
,Question 3
A patient is prescribed a drug that is highly protein-bound. The nurse practitioner should
monitor for which potential consequence?
A. Rapid renal excretion of the drug
B. Enhanced therapeutic effect at lower doses
C. Increased risk of drug interactions with other protein-bound drugs
D. Decreased risk of adverse effects
Correct Answer: C
Rationale: Highly protein-bound drugs compete for binding sites on plasma proteins. When
two protein-bound drugs are administered concurrently, one may displace the other, increasing
the free (active) concentration of the displaced drug and potentially causing toxicity. Protein-
binding capacity is a key factor affecting drug distribution .
Question 4 (SATA)
A nurse practitioner is teaching a patient about factors that affect drug distribution. Which of
the following are factors that influence drug distribution? (Select all that apply.)
A. Blood flow to tissues
B. Ability to exit the vascular system
C. Rate of dissolution
D. Protein-binding capacity
E. Blood-brain barrier
Correct Answers: A, B, D, E
Rationale: Factors affecting drug distribution include blood flow to tissues, ability of the
drug to exit the vascular system, blood-brain barrier penetration, and protein-binding capacity .
Rate of dissolution is a factor affecting absorption, not distribution.
Question 5
A patient taking warfarin is prescribed a drug that inhibits CYP2C9. The nurse practitioner
should anticipate which effect?
A. Decreased warfarin levels and increased clotting risk
B. Increased warfarin levels and increased bleeding risk
,C. No change in warfarin levels
D. Decreased warfarin absorption
Correct Answer: B
Rationale: Warfarin is metabolized by CYP2C9. Inhibiting this enzyme decreases warfarin
metabolism, leading to increased drug levels and an elevated INR, which increases bleeding risk.
Drug interactions can occur when two drugs compete for metabolizing enzymes .
Question 6
A patient of Asian descent is being considered for carbamazepine therapy. Which
pharmacogenomic consideration is most important?
A. CYP2D6 poor metabolizer status
B. HLA-B*1502 allele screening
C. G6PD deficiency testing
D. CYP2C19 ultrarapid metabolizer status
Correct Answer: B
Rationale: The HLA-B*1502 allele is strongly associated with an increased risk of Stevens-
Johnson syndrome and toxic epidermal necrolysis in patients of Asian descent taking
carbamazepine. Pharmacogenomic screening is recommended before initiating therapy in at-
risk populations .
Question 7
The therapeutic index of a drug is calculated as:
A. TD50/ED50
B. ED50/TD50
C. LD50/ED50
D. ED50/LD50
Correct Answer: A
Rationale: The therapeutic index is the ratio of the toxic dose (TD50) to the effective dose
(ED50). A higher therapeutic index indicates a wider margin of safety between therapeutic and
toxic effects .
, Question 8
Which mechanism of drug action involves a drug binding to a receptor and producing a maximal
response?
A. Partial agonist
B. Full agonist
C. Antagonist
D. Inverse agonist
Correct Answer: B
Rationale: A full agonist binds to a receptor and produces a maximal biologic response. A
partial agonist produces a submaximal response even at full receptor occupancy. Antagonists
block receptor activity, and inverse agonists produce effects opposite to those of agonists .
Question 9
A patient taking a drug with a narrow therapeutic index requires:
A. Standard dosing without monitoring
B. Routine therapeutic drug monitoring
C. No dose adjustments ever
D. Only PRN administration
Correct Answer: B
Rationale: Drugs with a narrow therapeutic index have a small margin between therapeutic
and toxic doses, requiring routine therapeutic drug monitoring to ensure levels remain within
the therapeutic range and to prevent toxicity .
Question 10
Which of the following describes an idiosyncratic drug effect?
A. A predictable, dose-dependent adverse reaction
B. An unexpected response to a medication
C. A therapeutic effect that occurs at high doses
D. A drug interaction between two medications
Correct Answer: B
Answers & Complete Review
Section 1: Pharmacokinetics, Pharmacodynamics & Pharmacogenomics
Question 1
A nurse practitioner is reviewing factors that influence drug absorption. Which of the following
factors would most likely increase the rate of drug absorption?
A. Increased gastric emptying time
B. High lipid solubility of the drug
C. Large molecular size of the drug
D. Decreased surface area for absorption
Correct Answer: B
Rationale: Lipid-soluble drugs cross biological membranes more readily via passive
diffusion, which speeds absorption. Factors that affect absorption include rate of dissolution,
surface area, blood flow, lipid solubility, and pH partitioning . Increased gastric emptying time
would delay absorption, while large molecular size and decreased surface area would reduce it.
Question 2
Which statement best describes pharmacodynamics?
A. The study of how the body affects a drug
B. The study of what the drug does to the body
C. The process of drug excretion
D. The movement of drugs across membranes
Correct Answer: B
Rationale: Pharmacodynamics is defined as the study of the biochemical and physiologic
effects of drugs on the body and the molecular mechanisms by which those effects are
produced — essentially “what the drug does to the body” . Pharmacokinetics describes “what
the body does to the drug,” including absorption, distribution, metabolism, and excretion.
,Question 3
A patient is prescribed a drug that is highly protein-bound. The nurse practitioner should
monitor for which potential consequence?
A. Rapid renal excretion of the drug
B. Enhanced therapeutic effect at lower doses
C. Increased risk of drug interactions with other protein-bound drugs
D. Decreased risk of adverse effects
Correct Answer: C
Rationale: Highly protein-bound drugs compete for binding sites on plasma proteins. When
two protein-bound drugs are administered concurrently, one may displace the other, increasing
the free (active) concentration of the displaced drug and potentially causing toxicity. Protein-
binding capacity is a key factor affecting drug distribution .
Question 4 (SATA)
A nurse practitioner is teaching a patient about factors that affect drug distribution. Which of
the following are factors that influence drug distribution? (Select all that apply.)
A. Blood flow to tissues
B. Ability to exit the vascular system
C. Rate of dissolution
D. Protein-binding capacity
E. Blood-brain barrier
Correct Answers: A, B, D, E
Rationale: Factors affecting drug distribution include blood flow to tissues, ability of the
drug to exit the vascular system, blood-brain barrier penetration, and protein-binding capacity .
Rate of dissolution is a factor affecting absorption, not distribution.
Question 5
A patient taking warfarin is prescribed a drug that inhibits CYP2C9. The nurse practitioner
should anticipate which effect?
A. Decreased warfarin levels and increased clotting risk
B. Increased warfarin levels and increased bleeding risk
,C. No change in warfarin levels
D. Decreased warfarin absorption
Correct Answer: B
Rationale: Warfarin is metabolized by CYP2C9. Inhibiting this enzyme decreases warfarin
metabolism, leading to increased drug levels and an elevated INR, which increases bleeding risk.
Drug interactions can occur when two drugs compete for metabolizing enzymes .
Question 6
A patient of Asian descent is being considered for carbamazepine therapy. Which
pharmacogenomic consideration is most important?
A. CYP2D6 poor metabolizer status
B. HLA-B*1502 allele screening
C. G6PD deficiency testing
D. CYP2C19 ultrarapid metabolizer status
Correct Answer: B
Rationale: The HLA-B*1502 allele is strongly associated with an increased risk of Stevens-
Johnson syndrome and toxic epidermal necrolysis in patients of Asian descent taking
carbamazepine. Pharmacogenomic screening is recommended before initiating therapy in at-
risk populations .
Question 7
The therapeutic index of a drug is calculated as:
A. TD50/ED50
B. ED50/TD50
C. LD50/ED50
D. ED50/LD50
Correct Answer: A
Rationale: The therapeutic index is the ratio of the toxic dose (TD50) to the effective dose
(ED50). A higher therapeutic index indicates a wider margin of safety between therapeutic and
toxic effects .
, Question 8
Which mechanism of drug action involves a drug binding to a receptor and producing a maximal
response?
A. Partial agonist
B. Full agonist
C. Antagonist
D. Inverse agonist
Correct Answer: B
Rationale: A full agonist binds to a receptor and produces a maximal biologic response. A
partial agonist produces a submaximal response even at full receptor occupancy. Antagonists
block receptor activity, and inverse agonists produce effects opposite to those of agonists .
Question 9
A patient taking a drug with a narrow therapeutic index requires:
A. Standard dosing without monitoring
B. Routine therapeutic drug monitoring
C. No dose adjustments ever
D. Only PRN administration
Correct Answer: B
Rationale: Drugs with a narrow therapeutic index have a small margin between therapeutic
and toxic doses, requiring routine therapeutic drug monitoring to ensure levels remain within
the therapeutic range and to prevent toxicity .
Question 10
Which of the following describes an idiosyncratic drug effect?
A. A predictable, dose-dependent adverse reaction
B. An unexpected response to a medication
C. A therapeutic effect that occurs at high doses
D. A drug interaction between two medications
Correct Answer: B
