NR 565 FINAL EXAM ADVANCED PHARMACOLOGY 2026/2027 |
Complete 220 Questions with Detailed Verified Answers | 100%
Correct | Already Graded A+ | Pass Guaranteed
Section 1: Pharmacokinetics, Pharmacodynamics & Pharmacogenomics (Q1-25)
Q1. A 45-year-old patient with major depressive disorder is prescribed codeine 30 mg
every 6 hours for postoperative pain. The patient reports minimal pain relief after 48
hours. Genetic testing reveals the patient is a CYP2D6 poor metabolizer. Which
pharmacogenomic principle best explains this clinical observation?
A. CYP2D6 poor metabolizers convert codeine to its active metabolite morphine at a
reduced rate, resulting in inadequate analgesia
B. CYP2D6 poor metabolizers rapidly clear codeine from the body, preventing
therapeutic plasma concentrations
C. CYP2D6 polymorphisms affect codeine's protein binding, increasing its volume of
distribution
D. CYP2D6 poor metabolizers produce excessive morphine, causing toxicity rather than
inefficacy
Correct Answer: A. CYP2D6 poor metabolizers convert codeine to its active metabolite
morphine at a reduced rate, resulting in inadequate analgesia [CORRECT]
Rationale: Codeine is a prodrug requiring CYP2D6-mediated O-demethylation to
morphine for analgesic effect. Poor metabolizers (PMs) have significantly reduced or
,absent CYP2D6 activity, yielding minimal morphine conversion and therapeutic failure.
Option B incorrectly describes rapid clearance; C misattributes the mechanism to
protein binding; D describes ultra-rapid metabolizer toxicity. Per FDA 2023 guidance and
CPIC guidelines, CYP2D6 PMs should avoid codeine and tramadol.
Q2. A 68-year-old patient on warfarin 5 mg daily achieves a therapeutic INR of 2.5. After
starting omeprazole 20 mg daily for GERD, the INR increases to 4.2. Which
pharmacokinetic interaction mechanism best explains this finding?
A. Omeprazole inhibits CYP2C19, reducing the metabolism of the more potent
S-warfarin enantiomer
B. Omeprazole inhibits CYP3A4, reducing R-warfarin clearance and increasing
S-warfarin plasma concentrations
C. Omeprazole inhibits CYP2C9, reducing the metabolism of the more potent S-warfarin
enantiomer
D. Omeprazole induces CYP1A2, increasing warfarin protein binding and free fraction
Correct Answer: C. Omeprazole inhibits CYP2C9, reducing the metabolism of the more
potent S-warfarin enantiomer [CORRECT]
Rationale: S-warfarin (2-5x more potent than R-warfarin) is primarily metabolized by
CYP2C9. Omeprazole is a moderate CYP2C9 inhibitor, reducing S-warfarin clearance
and increasing INR. Option A confuses CYP2C19 (omeprazole's primary metabolic
pathway) with warfarin metabolism; B incorrectly identifies CYP3A4 as the primary
pathway for S-warfarin; D describes an induction mechanism that would decrease, not
increase, INR.
,Q3. A patient with a history of myocardial infarction is prescribed clopidogrel 75 mg
daily. Pharmacogenomic testing reveals the patient is a CYP2C19 poor metabolizer.
Which clinical recommendation is most appropriate?
A. Continue clopidogrel at the standard dose because CYP2C19 polymorphisms do not
affect antiplatelet response
B. Switch to prasugrel or ticagrelor, as CYP2C19 poor metabolizers have reduced
generation of clopidogrel's active metabolite and increased cardiovascular event risk
C. Increase clopidogrel to 150 mg daily, as high-dose clopidogrel overcomes CYP2C19
poor metabolizer status
D. Add aspirin 81 mg daily to compensate for reduced clopidogrel activation
Correct Answer: B. Switch to prasugrel or ticagrelor, as CYP2C19 poor metabolizers
have reduced generation of clopidogrel's active metabolite and increased
cardiovascular event risk [CORRECT]
Rationale: Clopidogrel requires CYP2C19-mediated bioactivation to its active thiol
metabolite. CYP2C19 PMs exhibit reduced active metabolite levels, diminished platelet
inhibition, and higher cardiovascular event rates. Per 2022 ACC/AHA and CPIC
guidelines, switching to prasugrel or ticagrelor (which do not require CYP2C19
activation) is preferred. High-dose clopidogrel (option C) does not adequately overcome
PM status, and dual antiplatelet therapy (option D) does not address the underlying
pharmacogenomic issue.
, Q4. A 55-year-old patient with epilepsy on phenytoin 300 mg daily presents with
increased seizure frequency. Serum phenytoin level is 8 mcg/mL (therapeutic 10-20
mcg/mL). The patient recently started fluconazole 200 mg daily for esophageal
candidiasis. Which pharmacokinetic mechanism explains the subtherapeutic phenytoin
level?
A. Fluconazole induces CYP2C9, increasing phenytoin metabolism
B. Fluconazole inhibits CYP2C9, which should increase, not decrease, phenytoin levels
C. Fluconazole induces CYP3A4, increasing phenytoin metabolism
D. Fluconazole inhibits CYP2C9, but the patient has CYP2C9*3/*3 genotype causing
paradoxical decreased phenytoin levels
Correct Answer: B. Fluconazole inhibits CYP2C9, which should increase, not decrease,
phenytoin levels [CORRECT]
Rationale: This question tests analytical reasoning. Fluconazole is a potent CYP2C9
inhibitor that should increase phenytoin levels. The subtherapeutic level despite
fluconazole suggests nonadherence, malabsorption, or assay interference. Option B
correctly identifies the pharmacokinetic paradox requiring further investigation. Options
A and C incorrectly describe induction; D presents a fictional paradoxical interaction. Per
2026 clinical pharmacology principles, when expected drug interactions do not produce
predicted effects, adherence and assay issues must be evaluated.
Q5. A patient with rheumatoid arthritis is prescribed azathioprine 150 mg daily. Prior to
initiation, TPMT (thiopurine S-methyltransferase) testing reveals homozygous
deficiency. Which prescribing adjustment is most appropriate?
Complete 220 Questions with Detailed Verified Answers | 100%
Correct | Already Graded A+ | Pass Guaranteed
Section 1: Pharmacokinetics, Pharmacodynamics & Pharmacogenomics (Q1-25)
Q1. A 45-year-old patient with major depressive disorder is prescribed codeine 30 mg
every 6 hours for postoperative pain. The patient reports minimal pain relief after 48
hours. Genetic testing reveals the patient is a CYP2D6 poor metabolizer. Which
pharmacogenomic principle best explains this clinical observation?
A. CYP2D6 poor metabolizers convert codeine to its active metabolite morphine at a
reduced rate, resulting in inadequate analgesia
B. CYP2D6 poor metabolizers rapidly clear codeine from the body, preventing
therapeutic plasma concentrations
C. CYP2D6 polymorphisms affect codeine's protein binding, increasing its volume of
distribution
D. CYP2D6 poor metabolizers produce excessive morphine, causing toxicity rather than
inefficacy
Correct Answer: A. CYP2D6 poor metabolizers convert codeine to its active metabolite
morphine at a reduced rate, resulting in inadequate analgesia [CORRECT]
Rationale: Codeine is a prodrug requiring CYP2D6-mediated O-demethylation to
morphine for analgesic effect. Poor metabolizers (PMs) have significantly reduced or
,absent CYP2D6 activity, yielding minimal morphine conversion and therapeutic failure.
Option B incorrectly describes rapid clearance; C misattributes the mechanism to
protein binding; D describes ultra-rapid metabolizer toxicity. Per FDA 2023 guidance and
CPIC guidelines, CYP2D6 PMs should avoid codeine and tramadol.
Q2. A 68-year-old patient on warfarin 5 mg daily achieves a therapeutic INR of 2.5. After
starting omeprazole 20 mg daily for GERD, the INR increases to 4.2. Which
pharmacokinetic interaction mechanism best explains this finding?
A. Omeprazole inhibits CYP2C19, reducing the metabolism of the more potent
S-warfarin enantiomer
B. Omeprazole inhibits CYP3A4, reducing R-warfarin clearance and increasing
S-warfarin plasma concentrations
C. Omeprazole inhibits CYP2C9, reducing the metabolism of the more potent S-warfarin
enantiomer
D. Omeprazole induces CYP1A2, increasing warfarin protein binding and free fraction
Correct Answer: C. Omeprazole inhibits CYP2C9, reducing the metabolism of the more
potent S-warfarin enantiomer [CORRECT]
Rationale: S-warfarin (2-5x more potent than R-warfarin) is primarily metabolized by
CYP2C9. Omeprazole is a moderate CYP2C9 inhibitor, reducing S-warfarin clearance
and increasing INR. Option A confuses CYP2C19 (omeprazole's primary metabolic
pathway) with warfarin metabolism; B incorrectly identifies CYP3A4 as the primary
pathway for S-warfarin; D describes an induction mechanism that would decrease, not
increase, INR.
,Q3. A patient with a history of myocardial infarction is prescribed clopidogrel 75 mg
daily. Pharmacogenomic testing reveals the patient is a CYP2C19 poor metabolizer.
Which clinical recommendation is most appropriate?
A. Continue clopidogrel at the standard dose because CYP2C19 polymorphisms do not
affect antiplatelet response
B. Switch to prasugrel or ticagrelor, as CYP2C19 poor metabolizers have reduced
generation of clopidogrel's active metabolite and increased cardiovascular event risk
C. Increase clopidogrel to 150 mg daily, as high-dose clopidogrel overcomes CYP2C19
poor metabolizer status
D. Add aspirin 81 mg daily to compensate for reduced clopidogrel activation
Correct Answer: B. Switch to prasugrel or ticagrelor, as CYP2C19 poor metabolizers
have reduced generation of clopidogrel's active metabolite and increased
cardiovascular event risk [CORRECT]
Rationale: Clopidogrel requires CYP2C19-mediated bioactivation to its active thiol
metabolite. CYP2C19 PMs exhibit reduced active metabolite levels, diminished platelet
inhibition, and higher cardiovascular event rates. Per 2022 ACC/AHA and CPIC
guidelines, switching to prasugrel or ticagrelor (which do not require CYP2C19
activation) is preferred. High-dose clopidogrel (option C) does not adequately overcome
PM status, and dual antiplatelet therapy (option D) does not address the underlying
pharmacogenomic issue.
, Q4. A 55-year-old patient with epilepsy on phenytoin 300 mg daily presents with
increased seizure frequency. Serum phenytoin level is 8 mcg/mL (therapeutic 10-20
mcg/mL). The patient recently started fluconazole 200 mg daily for esophageal
candidiasis. Which pharmacokinetic mechanism explains the subtherapeutic phenytoin
level?
A. Fluconazole induces CYP2C9, increasing phenytoin metabolism
B. Fluconazole inhibits CYP2C9, which should increase, not decrease, phenytoin levels
C. Fluconazole induces CYP3A4, increasing phenytoin metabolism
D. Fluconazole inhibits CYP2C9, but the patient has CYP2C9*3/*3 genotype causing
paradoxical decreased phenytoin levels
Correct Answer: B. Fluconazole inhibits CYP2C9, which should increase, not decrease,
phenytoin levels [CORRECT]
Rationale: This question tests analytical reasoning. Fluconazole is a potent CYP2C9
inhibitor that should increase phenytoin levels. The subtherapeutic level despite
fluconazole suggests nonadherence, malabsorption, or assay interference. Option B
correctly identifies the pharmacokinetic paradox requiring further investigation. Options
A and C incorrectly describe induction; D presents a fictional paradoxical interaction. Per
2026 clinical pharmacology principles, when expected drug interactions do not produce
predicted effects, adherence and assay issues must be evaluated.
Q5. A patient with rheumatoid arthritis is prescribed azathioprine 150 mg daily. Prior to
initiation, TPMT (thiopurine S-methyltransferase) testing reveals homozygous
deficiency. Which prescribing adjustment is most appropriate?
