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NURS 6521 Advanced Pharmacology Midterm
Exam Walden University 100 Questions and
Answers Actual Exam 2026/2027 Complete
Exam-Style Questions with Detailed Rationales |
100% Verified | Pass Guaranteed – A+ Graded
Part I: Pharmacokinetics, Pharmacodynamics & Individual
Variation (Questions 1-20)
Q1: A 67-year-old female with chronic kidney disease (CrCl 28
mL/min) is prescribed a medication that is primarily eliminated
renally. The drug has a narrow therapeutic index and normally
requires dosing every 12 hours. What is the most appropriate
prescribing adjustment for this patient?
A. Increase the dose by 50% to compensate for reduced renal
clearance
B. Extend the dosing interval to every 24 hours and consider
reducing the dose by 25–50%
C. Maintain standard dosing but add therapeutic drug
monitoring after the first dose
D. Switch to an entirely different drug class regardless of
indication [CORRECT]
Correct Answer: B
,2
Rationale: For renally cleared drugs with a narrow therapeutic
index, extending the dosing interval while potentially reducing
the dose is the standard approach to prevent drug accumulation
and toxicity in patients with significantly impaired renal
function (CrCl <30 mL/min). This follows the pharmacokinetic
principle that elimination half-life increases as renal clearance
decreases.
Q2: Which cytochrome P450 enzyme is most responsible for
metabolizing the majority of commonly prescribed medications
and is also the most clinically significant site of drug-drug
interactions?
A. CYP2C9
B. CYP3A4 [CORRECT]
C. CYP2D6
D. CYP1A2
Correct Answer: B
Rationale: CYP3A4 is the most abundant CYP450 isoform in
the liver and gut, responsible for metabolizing approximately
50% of all marketed drugs. This makes it the single most
,3
important enzyme for understanding and predicting drug-drug
interactions in clinical practice.
Q3: A 54-year-old male presents to your clinic taking warfarin
for atrial fibrillation. He recently started taking St. John's wort
for mild depression on his own. Three weeks later, his INR
drops from 2.5 to 1.3 despite no dose changes. What is the most
likely explanation?
A. St. John's wort inhibits vitamin K epoxide reductase,
counteracting warfarin
B. St. John's wort induces CYP2C9 and possibly P-glycoprotein,
increasing warfarin metabolism [CORRECT]
C. The patient has developed subtherapeutic absorption due to
GI interactions
D. Warfarin resistance has developed from chronic use
Correct Answer: B
Rationale: St. John's wort is a potent inducer of CYP2C9 (the
primary metabolizing enzyme for warfarin) and P-glycoprotein.
This induction accelerates warfarin clearance, leading to
decreased anticoagulant effect and a drop in INR—a classic and
clinically important herb-drug interaction that prescribers must
recognize.
, 4
Q4: A patient undergoes pharmacogenomic testing before
starting clopidogrel following a cardiac stent placement. Results
show they are a CYP2C19 poor metabolizer. How should this
finding influence prescribing?
A. No change needed; give standard clopidogrel dosing
B. Increase clopidogrel dose to 150 mg daily to overcome poor
metabolism
C. Consider alternative antiplatelet therapy such as prasugrel or
ticagrelor [CORRECT]
D. Add aspirin 81 mg daily to compensate
Correct Answer: C
Rationale: CYP2C19 poor metabolizers cannot adequately
convert clopidogrel (a prodrug) into its active metabolite,
resulting in reduced antiplatelet effect and higher risk of stent
thrombosis. Current guidelines recommend considering
alternative P2Y12 inhibitors like prasugrel or ticagrelor, which
do not rely on CYP2C19 activation, for these patients.
NURS 6521 Advanced Pharmacology Midterm
Exam Walden University 100 Questions and
Answers Actual Exam 2026/2027 Complete
Exam-Style Questions with Detailed Rationales |
100% Verified | Pass Guaranteed – A+ Graded
Part I: Pharmacokinetics, Pharmacodynamics & Individual
Variation (Questions 1-20)
Q1: A 67-year-old female with chronic kidney disease (CrCl 28
mL/min) is prescribed a medication that is primarily eliminated
renally. The drug has a narrow therapeutic index and normally
requires dosing every 12 hours. What is the most appropriate
prescribing adjustment for this patient?
A. Increase the dose by 50% to compensate for reduced renal
clearance
B. Extend the dosing interval to every 24 hours and consider
reducing the dose by 25–50%
C. Maintain standard dosing but add therapeutic drug
monitoring after the first dose
D. Switch to an entirely different drug class regardless of
indication [CORRECT]
Correct Answer: B
,2
Rationale: For renally cleared drugs with a narrow therapeutic
index, extending the dosing interval while potentially reducing
the dose is the standard approach to prevent drug accumulation
and toxicity in patients with significantly impaired renal
function (CrCl <30 mL/min). This follows the pharmacokinetic
principle that elimination half-life increases as renal clearance
decreases.
Q2: Which cytochrome P450 enzyme is most responsible for
metabolizing the majority of commonly prescribed medications
and is also the most clinically significant site of drug-drug
interactions?
A. CYP2C9
B. CYP3A4 [CORRECT]
C. CYP2D6
D. CYP1A2
Correct Answer: B
Rationale: CYP3A4 is the most abundant CYP450 isoform in
the liver and gut, responsible for metabolizing approximately
50% of all marketed drugs. This makes it the single most
,3
important enzyme for understanding and predicting drug-drug
interactions in clinical practice.
Q3: A 54-year-old male presents to your clinic taking warfarin
for atrial fibrillation. He recently started taking St. John's wort
for mild depression on his own. Three weeks later, his INR
drops from 2.5 to 1.3 despite no dose changes. What is the most
likely explanation?
A. St. John's wort inhibits vitamin K epoxide reductase,
counteracting warfarin
B. St. John's wort induces CYP2C9 and possibly P-glycoprotein,
increasing warfarin metabolism [CORRECT]
C. The patient has developed subtherapeutic absorption due to
GI interactions
D. Warfarin resistance has developed from chronic use
Correct Answer: B
Rationale: St. John's wort is a potent inducer of CYP2C9 (the
primary metabolizing enzyme for warfarin) and P-glycoprotein.
This induction accelerates warfarin clearance, leading to
decreased anticoagulant effect and a drop in INR—a classic and
clinically important herb-drug interaction that prescribers must
recognize.
, 4
Q4: A patient undergoes pharmacogenomic testing before
starting clopidogrel following a cardiac stent placement. Results
show they are a CYP2C19 poor metabolizer. How should this
finding influence prescribing?
A. No change needed; give standard clopidogrel dosing
B. Increase clopidogrel dose to 150 mg daily to overcome poor
metabolism
C. Consider alternative antiplatelet therapy such as prasugrel or
ticagrelor [CORRECT]
D. Add aspirin 81 mg daily to compensate
Correct Answer: C
Rationale: CYP2C19 poor metabolizers cannot adequately
convert clopidogrel (a prodrug) into its active metabolite,
resulting in reduced antiplatelet effect and higher risk of stent
thrombosis. Current guidelines recommend considering
alternative P2Y12 inhibitors like prasugrel or ticagrelor, which
do not rely on CYP2C19 activation, for these patients.
