WGU D345 NURS 6438 Psychopharmacology Final OA Exam
Question Bank (Latest 2026/2027 Edition) – 100% Correct
Questions, Answers & Detailed Rationales
Total Questions: 60
Time Allowed: 120 Minutes
Passing Score: 80%
Instructions: Select the BEST answer for each question based on psychopharmacology
principles, mechanisms of action, side effect profiles, and evidence-based prescribing
practices. For SATA questions, select all that apply.
SECTION 1: FOUNDATIONAL NEUROSCIENCE & PHARMACOKINETICS
Questions 1–12
Question 1
A 45-year-old man is prescribed fluoxetine 20 mg daily. He is also a poor metabolizer of
CYP2D6. Which clinical consequence is MOST likely due to this genetic polymorphism?
A. Rapid clearance of fluoxetine requiring higher doses
B. Increased plasma levels of fluoxetine and higher risk of side effects
C. Reduced bioavailability of fluoxetine due to first-pass metabolism
D. Decreased half-life requiring twice-daily dosing
Correct Answer: B
Rationale: CYP2D6 poor metabolizers have reduced enzymatic activity, leading to
decreased metabolism and increased plasma concentrations of CYP2D6 substrates like
fluoxetine. This increases the risk of side effects and drug interactions. Rapid clearance
(A) describes ultra-rapid metabolizers. First-pass metabolism (C) is primarily hepatic,
,not genetic polymorphism-specific. Decreased half-life (D) is opposite of what occurs in
poor metabolizers.
Question 2
Which of the following statements about pharmacokinetics are correct? Select all that
apply.
A. Absorption refers to the movement of drug from the site of administration into the
bloodstream
B. Distribution is influenced by protein binding and lipid solubility
C. Metabolism typically converts drugs into more water-soluble compounds for
excretion
D. The kidneys are the primary organ for drug excretion
E. Bioavailability is always 100% for oral medications
Correct Answers: A, B, C, D
Rationale: Absorption (A), distribution (B), metabolism (C), and excretion (D) are
correctly defined. Bioavailability (E) is rarely 100% for oral medications due to first-pass
hepatic metabolism and incomplete absorption; IV medications have 100%
bioavailability.
Question 3
A PMHNP is explaining ketamine's mechanism of action to a patient with
treatment-resistant depression. Which statement is MOST accurate?
A. "Ketamine selectively blocks serotonin reuptake to increase synaptic serotonin."
B. "Ketamine is an NMDA receptor antagonist that increases glutamate release and
promotes synaptogenesis."
C. "Ketamine enhances GABA-A receptor activity to produce rapid sedation."
D. "Ketamine inhibits monoamine oxidase to prevent neurotransmitter breakdown."
Correct Answer: B
,Rationale: Ketamine is a non-competitive NMDA receptor antagonist. Its antidepressant
effects are mediated through glutamate surge, activation of AMPA receptors, and
downstream mTOR signaling that promotes synaptogenesis and neural plasticity. It
does not primarily act on serotonin reuptake (A), GABA-A (C), or MAO (D).
Question 4
A patient asks why it takes 4–6 weeks for antidepressants to reach full therapeutic
effect despite starting the medication immediately. Which pharmacological concept
BEST explains this delay?
A. First-pass metabolism must be saturated before clinical effects occur
B. Steady-state concentration requires 4–5 half-lives to achieve
C. Receptor downregulation and neuroplastic changes require time
D. The blood-brain barrier prevents initial drug entry
Correct Answer: C
Rationale: While steady-state is reached in 4–5 half-lives (B), the delayed clinical
response to antidepressants is attributed to downstream neuroplastic changes,
including BDNF upregulation, neurogenesis, and receptor adaptations—not simply
achieving steady-state. First-pass saturation (A) and blood-brain barrier (D) do not
explain the therapeutic delay.
Question 5
Which of the following neurotransmitters is primarily synthesized in the basal nucleus
of Meynert and is critically involved in memory formation?
A. Dopamine
B. Serotonin
C. Acetylcholine
D. Norepinephrine
Correct Answer: C
, Rationale: The basal nucleus of Meynert is the primary source of cholinergic innervation
to the cerebral cortex and hippocampus. Degeneration of these neurons and cholinergic
deficiency is central to Alzheimer's disease pathophysiology. Dopamine (A) originates in
substantia nigra and VTA. Serotonin (B) from raphe nuclei. Norepinephrine (D) from
locus coeruleus.
Question 6
A 38-year-old woman is prescribed a medication that acts as a partial agonist at D2
receptors and an antagonist at 5-HT2A receptors. Which medication has this receptor
profile?
A. Haloperidol
B. Risperidone
C. Aripiprazole
D. Chlorpromazine
Correct Answer: C
Rationale: Aripiprazole is a D2 partial agonist and 5-HT1A partial agonist/5-HT2A
antagonist, described as a "dopamine system stabilizer." Haloperidol (A) and
chlorpromazine (D) are D2 antagonists (typical antipsychotics). Risperidone (B) is a D2
antagonist and 5-HT2A antagonist (atypical) but not a partial agonist.
Question 7
Which of the following statements about the CYP450 enzyme system are correct?
Select all that apply.
A. CYP2D6 is involved in the metabolism of many SSRIs and antipsychotics
B. Fluoxetine and paroxetine are potent CYP2D6 inhibitors
C. Genetic polymorphisms can result in ultra-rapid, extensive, intermediate, or poor
metabolizer phenotypes
D. CYP3A4 is inhibited by grapefruit juice
E. Drug interactions at CYP450 enzymes always result in decreased drug efficacy
Question Bank (Latest 2026/2027 Edition) – 100% Correct
Questions, Answers & Detailed Rationales
Total Questions: 60
Time Allowed: 120 Minutes
Passing Score: 80%
Instructions: Select the BEST answer for each question based on psychopharmacology
principles, mechanisms of action, side effect profiles, and evidence-based prescribing
practices. For SATA questions, select all that apply.
SECTION 1: FOUNDATIONAL NEUROSCIENCE & PHARMACOKINETICS
Questions 1–12
Question 1
A 45-year-old man is prescribed fluoxetine 20 mg daily. He is also a poor metabolizer of
CYP2D6. Which clinical consequence is MOST likely due to this genetic polymorphism?
A. Rapid clearance of fluoxetine requiring higher doses
B. Increased plasma levels of fluoxetine and higher risk of side effects
C. Reduced bioavailability of fluoxetine due to first-pass metabolism
D. Decreased half-life requiring twice-daily dosing
Correct Answer: B
Rationale: CYP2D6 poor metabolizers have reduced enzymatic activity, leading to
decreased metabolism and increased plasma concentrations of CYP2D6 substrates like
fluoxetine. This increases the risk of side effects and drug interactions. Rapid clearance
(A) describes ultra-rapid metabolizers. First-pass metabolism (C) is primarily hepatic,
,not genetic polymorphism-specific. Decreased half-life (D) is opposite of what occurs in
poor metabolizers.
Question 2
Which of the following statements about pharmacokinetics are correct? Select all that
apply.
A. Absorption refers to the movement of drug from the site of administration into the
bloodstream
B. Distribution is influenced by protein binding and lipid solubility
C. Metabolism typically converts drugs into more water-soluble compounds for
excretion
D. The kidneys are the primary organ for drug excretion
E. Bioavailability is always 100% for oral medications
Correct Answers: A, B, C, D
Rationale: Absorption (A), distribution (B), metabolism (C), and excretion (D) are
correctly defined. Bioavailability (E) is rarely 100% for oral medications due to first-pass
hepatic metabolism and incomplete absorption; IV medications have 100%
bioavailability.
Question 3
A PMHNP is explaining ketamine's mechanism of action to a patient with
treatment-resistant depression. Which statement is MOST accurate?
A. "Ketamine selectively blocks serotonin reuptake to increase synaptic serotonin."
B. "Ketamine is an NMDA receptor antagonist that increases glutamate release and
promotes synaptogenesis."
C. "Ketamine enhances GABA-A receptor activity to produce rapid sedation."
D. "Ketamine inhibits monoamine oxidase to prevent neurotransmitter breakdown."
Correct Answer: B
,Rationale: Ketamine is a non-competitive NMDA receptor antagonist. Its antidepressant
effects are mediated through glutamate surge, activation of AMPA receptors, and
downstream mTOR signaling that promotes synaptogenesis and neural plasticity. It
does not primarily act on serotonin reuptake (A), GABA-A (C), or MAO (D).
Question 4
A patient asks why it takes 4–6 weeks for antidepressants to reach full therapeutic
effect despite starting the medication immediately. Which pharmacological concept
BEST explains this delay?
A. First-pass metabolism must be saturated before clinical effects occur
B. Steady-state concentration requires 4–5 half-lives to achieve
C. Receptor downregulation and neuroplastic changes require time
D. The blood-brain barrier prevents initial drug entry
Correct Answer: C
Rationale: While steady-state is reached in 4–5 half-lives (B), the delayed clinical
response to antidepressants is attributed to downstream neuroplastic changes,
including BDNF upregulation, neurogenesis, and receptor adaptations—not simply
achieving steady-state. First-pass saturation (A) and blood-brain barrier (D) do not
explain the therapeutic delay.
Question 5
Which of the following neurotransmitters is primarily synthesized in the basal nucleus
of Meynert and is critically involved in memory formation?
A. Dopamine
B. Serotonin
C. Acetylcholine
D. Norepinephrine
Correct Answer: C
, Rationale: The basal nucleus of Meynert is the primary source of cholinergic innervation
to the cerebral cortex and hippocampus. Degeneration of these neurons and cholinergic
deficiency is central to Alzheimer's disease pathophysiology. Dopamine (A) originates in
substantia nigra and VTA. Serotonin (B) from raphe nuclei. Norepinephrine (D) from
locus coeruleus.
Question 6
A 38-year-old woman is prescribed a medication that acts as a partial agonist at D2
receptors and an antagonist at 5-HT2A receptors. Which medication has this receptor
profile?
A. Haloperidol
B. Risperidone
C. Aripiprazole
D. Chlorpromazine
Correct Answer: C
Rationale: Aripiprazole is a D2 partial agonist and 5-HT1A partial agonist/5-HT2A
antagonist, described as a "dopamine system stabilizer." Haloperidol (A) and
chlorpromazine (D) are D2 antagonists (typical antipsychotics). Risperidone (B) is a D2
antagonist and 5-HT2A antagonist (atypical) but not a partial agonist.
Question 7
Which of the following statements about the CYP450 enzyme system are correct?
Select all that apply.
A. CYP2D6 is involved in the metabolism of many SSRIs and antipsychotics
B. Fluoxetine and paroxetine are potent CYP2D6 inhibitors
C. Genetic polymorphisms can result in ultra-rapid, extensive, intermediate, or poor
metabolizer phenotypes
D. CYP3A4 is inhibited by grapefruit juice
E. Drug interactions at CYP450 enzymes always result in decreased drug efficacy
