WGU D116 Advanced Pharmacology Study Guide-
Practice Questions & Rationale Frameworks 2026
This comprehensive study resource features targeted practice assessments and
detailed rationale breakdowns designed specifically for Western Governors University’s
advanced pharmacology curriculum. It emphasizes complex pharmacokinetic profiles,
advanced pharmacodynamics, and individualized prescriptive authority reasoning
across diverse patient lifespans. Nursing students will build the diagnostic confidence
required to successfully master the objective assessment and safely prescribe in
advanced practice settings.
Question 1
A patient is prescribed a medication that is known to be a potent inhibitor of CYP2D6.
Which drug, if taken concurrently, would most likely accumulate and cause toxicity?
A. Warfarin (CYP2C9 substrate)
B. Metoprolol (CYP2D6 substrate)
C. Phenytoin (CYP2C9 substrate)
D. Omeprazole (CYP2C19 substrate)
Rationale: CYP2D6 inhibitors reduce the metabolism of CYP2D6 substrates like
metoprolol, leading to increased plasma levels and risk of bradycardia and hypotension.
Question 2
A patient with depression is prescribed fluoxetine. The prescriber should be concerned
about an interaction with which medication?
A. Amoxicillin
B. Tramadol
C. Acetaminophen
D. Lisinopril
,Rationale: Fluoxetine inhibits CYP2D6, which metabolizes tramadol. This interaction can
reduce tramadol's analgesic effect and increase risk of serotonin syndrome.
Question 3
A patient is taking phenytoin and is started on fluconazole. What is the expected effect?
A. Decreased phenytoin levels
B. Increased phenytoin levels and toxicity risk
C. No interaction
D. Increased fluconazole levels only
Rationale: Fluconazole inhibits CYP2C9, which metabolizes phenytoin. This can lead to
phenytoin toxicity (nystagmus, ataxia, confusion).
Question 4
Which medication is most likely to cause QT prolongation?
A. Amoxicillin
B. Azithromycin
C. Acetaminophen
D. Lisinopril
Rationale: Macrolide antibiotics like azithromycin can prolong the QT interval, increasing
risk of torsades de pointes.
Question 5
A patient on warfarin is prescribed trimethoprim-sulfamethoxazole for a UTI. What
should the prescriber anticipate?
,A. Decreased INR
B. Increased INR and bleeding risk
C. No change in INR
D. Warfarin resistance
Rationale: TMP-SMX inhibits CYP2C9 and displaces warfarin from protein binding,
increasing INR and bleeding risk.
Question 6
Which medication requires monitoring of serum creatinine and BUN?
A. Amoxicillin
B. Vancomycin
C. Azithromycin
D. Doxycycline
Rationale: Vancomycin is nephrotoxic and requires monitoring of renal function
(creatinine, BUN) to prevent acute kidney injury.
Question 7
A patient on digoxin is prescribed furosemide. Which electrolyte imbalance increases
the risk of digoxin toxicity?
A. Hyperkalemia
B. Hypokalemia
C. Hypernatremia
D. Hypercalcemia
Rationale: Hypokalemia (caused by loop diuretics like furosemide) increases the risk of
digoxin toxicity by enhancing digoxin binding to Na+/K+ ATPase.
, Question 8
Which medication is a direct oral anticoagulant (DOAC)?
A. Warfarin
B. Heparin
C. Apixaban
D. Enoxaparin
Rationale: Apixaban (Eliquis) is a direct oral anticoagulant that inhibits factor Xa. It does
not require routine INR monitoring.
Question 9
A patient is prescribed levothyroxine. Which medication, if taken concurrently, would
decrease its absorption?
A. Vitamin C
B. Calcium carbonate
C. Folic acid
D. Vitamin D
Rationale: Calcium can bind to levothyroxine in the GI tract and decrease its absorption.
Patients should separate administration by at least 4 hours.
Question 10
A patient is prescribed metformin. Which laboratory value should be monitored to
assess for a rare but serious adverse effect?
A. Serum potassium
B. Serum lactate
C. Serum sodium
D. Serum calcium
Rationale: Metformin can cause lactic acidosis, a rare but life-threatening condition.
Serum lactate should be monitored in at-risk patients.
Practice Questions & Rationale Frameworks 2026
This comprehensive study resource features targeted practice assessments and
detailed rationale breakdowns designed specifically for Western Governors University’s
advanced pharmacology curriculum. It emphasizes complex pharmacokinetic profiles,
advanced pharmacodynamics, and individualized prescriptive authority reasoning
across diverse patient lifespans. Nursing students will build the diagnostic confidence
required to successfully master the objective assessment and safely prescribe in
advanced practice settings.
Question 1
A patient is prescribed a medication that is known to be a potent inhibitor of CYP2D6.
Which drug, if taken concurrently, would most likely accumulate and cause toxicity?
A. Warfarin (CYP2C9 substrate)
B. Metoprolol (CYP2D6 substrate)
C. Phenytoin (CYP2C9 substrate)
D. Omeprazole (CYP2C19 substrate)
Rationale: CYP2D6 inhibitors reduce the metabolism of CYP2D6 substrates like
metoprolol, leading to increased plasma levels and risk of bradycardia and hypotension.
Question 2
A patient with depression is prescribed fluoxetine. The prescriber should be concerned
about an interaction with which medication?
A. Amoxicillin
B. Tramadol
C. Acetaminophen
D. Lisinopril
,Rationale: Fluoxetine inhibits CYP2D6, which metabolizes tramadol. This interaction can
reduce tramadol's analgesic effect and increase risk of serotonin syndrome.
Question 3
A patient is taking phenytoin and is started on fluconazole. What is the expected effect?
A. Decreased phenytoin levels
B. Increased phenytoin levels and toxicity risk
C. No interaction
D. Increased fluconazole levels only
Rationale: Fluconazole inhibits CYP2C9, which metabolizes phenytoin. This can lead to
phenytoin toxicity (nystagmus, ataxia, confusion).
Question 4
Which medication is most likely to cause QT prolongation?
A. Amoxicillin
B. Azithromycin
C. Acetaminophen
D. Lisinopril
Rationale: Macrolide antibiotics like azithromycin can prolong the QT interval, increasing
risk of torsades de pointes.
Question 5
A patient on warfarin is prescribed trimethoprim-sulfamethoxazole for a UTI. What
should the prescriber anticipate?
,A. Decreased INR
B. Increased INR and bleeding risk
C. No change in INR
D. Warfarin resistance
Rationale: TMP-SMX inhibits CYP2C9 and displaces warfarin from protein binding,
increasing INR and bleeding risk.
Question 6
Which medication requires monitoring of serum creatinine and BUN?
A. Amoxicillin
B. Vancomycin
C. Azithromycin
D. Doxycycline
Rationale: Vancomycin is nephrotoxic and requires monitoring of renal function
(creatinine, BUN) to prevent acute kidney injury.
Question 7
A patient on digoxin is prescribed furosemide. Which electrolyte imbalance increases
the risk of digoxin toxicity?
A. Hyperkalemia
B. Hypokalemia
C. Hypernatremia
D. Hypercalcemia
Rationale: Hypokalemia (caused by loop diuretics like furosemide) increases the risk of
digoxin toxicity by enhancing digoxin binding to Na+/K+ ATPase.
, Question 8
Which medication is a direct oral anticoagulant (DOAC)?
A. Warfarin
B. Heparin
C. Apixaban
D. Enoxaparin
Rationale: Apixaban (Eliquis) is a direct oral anticoagulant that inhibits factor Xa. It does
not require routine INR monitoring.
Question 9
A patient is prescribed levothyroxine. Which medication, if taken concurrently, would
decrease its absorption?
A. Vitamin C
B. Calcium carbonate
C. Folic acid
D. Vitamin D
Rationale: Calcium can bind to levothyroxine in the GI tract and decrease its absorption.
Patients should separate administration by at least 4 hours.
Question 10
A patient is prescribed metformin. Which laboratory value should be monitored to
assess for a rare but serious adverse effect?
A. Serum potassium
B. Serum lactate
C. Serum sodium
D. Serum calcium
Rationale: Metformin can cause lactic acidosis, a rare but life-threatening condition.
Serum lactate should be monitored in at-risk patients.
