NURS 6521 ADVANCED PHARMACOLOGY
FINAL EXAM
NURS 6521N Week 11 | Version A | 100 Questions with Correct Answers
Walden University | 2026-2027 Curriculum | A+ Grade Verified
Exam Format: Multiple Choice (4 options, A-D) Total Questions: 100
Cognitive Levels: 25% Recall, 50% Application, 25% Analysis Passing Standard: A+ Grade
Section 1: Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics (Q1-Q15)
Q1: A 45-year-old patient is prescribed a medication with high first-pass metabolism. The nurse practitioner
understands that which of the following best describes the consequence of first-pass metabolism on this drug?
A. The drug will have a prolonged half-life requiring less frequent dosing
B. A significant portion of the oral dose is metabolized before reaching systemic circulation, reducing bioavailability
[CORRECT]
C. The drug will be primarily excreted unchanged by the kidneys
D. First-pass metabolism increases the drug's volume of distribution
Correct Answer: B
Rationale: First-pass metabolism refers to the pre-systemic metabolism of a drug in the liver and/or intestinal wall before it
reaches the systemic circulation. Drugs with high first-pass metabolism (e.g., propranolol, morphine, verapamil) have
significantly reduced oral bioavailability, often requiring higher oral doses compared to parenteral administration. Options A,
C, and D are incorrect because first-pass metabolism does not directly determine half-life, renal excretion, or volume of
distribution.
Q2: A nurse practitioner is reviewing the pharmacokinetic profile of a new drug. The drug has a volume of
distribution (Vd) of 500 L in a 70-kg patient. What does this value most likely indicate about the drug's properties?
A. The drug is hydrophilic and remains primarily in the plasma compartment
B. The drug is extensively bound to plasma proteins
C. The drug is highly lipophilic and distributes widely into tissues, including adipose tissue [CORRECT]
D. The drug is confined to the extracellular fluid space
Correct Answer: C
Rationale: A Vd of 500 L in a 70-kg patient greatly exceeds total body water (approximately 42 L), indicating extensive tissue
distribution. This is characteristic of lipophilic drugs that readily cross cell membranes and accumulate in adipose tissue and
other body compartments. Drugs like digoxin (Vd ~500 L) and amiodarone (Vd ~70 L/kg) exemplify this pattern. Options A
and D would show Vd values approximating plasma volume (~3-5 L) or extracellular fluid (~12-15 L) respectively. Option B
describes protein binding, which reduces free drug available for distribution.
Q3: A patient with chronic liver disease is prescribed a medication that is a CYP3A4 substrate. The nurse
practitioner should anticipate which of the following pharmacokinetic changes?
A. Increased first-pass metabolism leading to decreased drug levels
B. Decreased hepatic clearance leading to increased drug plasma concentrations and potential toxicity
[CORRECT]
NURS 6521 Advanced Pharmacology Final Exam Page 1
, C. Enhanced renal excretion compensating for reduced hepatic metabolism
D. No significant change because CYP3A4 is not affected by liver disease
Correct Answer: B
Rationale: In chronic liver disease, hepatic blood flow decreases and CYP450 enzyme activity (including CYP3A4) is
impaired, particularly in cirrhosis. This results in decreased hepatic clearance of CYP3A4 substrates, leading to increased
plasma drug concentrations and higher risk of toxicity. The nurse practitioner should consider dose reduction and therapeutic
drug monitoring. Option A is incorrect because first-pass metabolism is reduced, not increased. Option C incorrectly
suggests renal compensation. Option D is false because liver disease significantly affects CYP3A4 activity.
Q4: A 30-year-old female patient of Asian descent is prescribed codeine for post-operative pain. Genetic testing
reveals she is a CYP2D6 ultra-rapid metabolizer. What clinical effect should the nurse practitioner anticipate?
A. Therapeutic analgesia with standard dosing due to efficient conversion to morphine
B. No analgesic effect because codeine cannot be converted to its active metabolite
C. Excessive morphine formation leading to respiratory depression and potential opioid toxicity even at standard
doses [CORRECT]
D. Prolonged codeine half-life due to impaired metabolism
Correct Answer: C
Rationale: Codeine is a prodrug that requires CYP2D6-mediated O-demethylation to morphine for analgesic effect.
Ultra-rapid CYP2D6 metabolizers convert codeine to morphine at an accelerated rate, producing dangerously high morphine
levels. This has led to fatal respiratory depression, particularly in pediatric patients. The FDA has issued a boxed warning
against codeine use in CYP2D6 ultra-rapid metabolizers and in children post-tonsillectomy. Option A underestimates the risk.
Option B describes poor metabolizers. Option D describes poor metabolizers, not ultra-rapid metabolizers.
Q5: A patient taking warfarin is started on amiodarone for atrial fibrillation. The nurse practitioner understands that
this drug interaction is primarily due to which mechanism?
A. Amiodarone induces CYP2C9, increasing warfarin metabolism and decreasing INR
B. Amiodarone inhibits CYP2C9, decreasing warfarin metabolism and increasing INR and bleeding risk
[CORRECT]
C. Amiodarone decreases warfarin protein binding, increasing free warfarin levels transiently
D. Amiodarone increases renal clearance of warfarin, reducing its anticoagulant effect
Correct Answer: B
Rationale: Amiodarone is a potent inhibitor of CYP2C9, the primary enzyme responsible for metabolizing S-warfarin (the
more potent enantiomer). Inhibition of CYP2C9 reduces warfarin clearance, leading to increased INR and elevated bleeding
risk. The warfarin dose should typically be reduced by 30-50% when amiodarone is initiated, with close INR monitoring. This
interaction can persist for weeks after amiodarone discontinuation due to its extremely long half-life. Option A incorrectly
describes induction. Options C and D describe mechanisms not relevant to this interaction.
Q6: A nurse practitioner is explaining pharmacodynamics to a nursing student. Which statement best describes
the concept of efficacy as it relates to drug-receptor interaction?
A. The ability of a drug to bind to a receptor
B. The concentration of drug required to produce 50% of the maximum effect
C. The maximum effect a drug can produce when all available receptors are occupied, regardless of dose
[CORRECT]
D. The rate at which a drug is eliminated from the body
Correct Answer: C
Rationale: Efficacy (Emax) refers to the maximum pharmacological effect a drug can produce when all available receptors
are occupied or the drug's intrinsic ability to activate a response. It is an important distinction from potency, which relates to
the dose needed to achieve a given effect. A drug with high efficacy is a full agonist, while a partial agonist has lower efficacy
NURS 6521 Advanced Pharmacology Final Exam Page 2
, even at full receptor occupancy. Option A describes affinity. Option B describes EC50 (potency). Option D describes
elimination, a pharmacokinetic concept.
Q7: A 60-year-old patient with a history of myocardial infarction is prescribed atenolol. The nurse practitioner
explains that atenolol is a cardioselective beta-1 blocker. Which clinical effect is most directly mediated by beta-1
receptor blockade?
A. Bronchodilation
B. Decreased heart rate and decreased cardiac output [CORRECT]
C. Vasodilation of skeletal muscle arterioles
D. Decreased glycogenolysis in skeletal muscle
Correct Answer: B
Rationale: Beta-1 receptors are primarily located in the heart (SA node, AV node, and ventricular myocardium). Blockade of
beta-1 receptors reduces heart rate (negative chronotropy), decreases conduction velocity through the AV node (negative
dromotropy), and reduces myocardial contractility (negative inotropy), collectively decreasing cardiac output. Atenolol is
considered cardioselective at low doses, making it preferred over nonselective beta-blockers in patients with mild respiratory
disease. Option A (bronchodilation) and Option C (vasodilation) are beta-2 effects. Option D is also a beta-2 mediated effect.
Q8: A patient is prescribed a drug with a half-life of 12 hours. Approximately how long will it take to reach
steady-state plasma concentrations with consistent dosing?
A. 12 hours
B. 24 hours
C. 48 to 60 hours (approximately 4-5 half-lives) [CORRECT]
D. 120 hours (approximately 10 half-lives)
Correct Answer: C
Rationale: Steady-state concentration is achieved when the rate of drug administration equals the rate of elimination. It takes
approximately 4-5 half-lives to reach approximately 94-97% of steady state. For a drug with a 12-hour half-life, steady state
would be reached in approximately 48-60 hours. This pharmacokinetic principle is fundamental for determining when to
assess drug efficacy and adjust doses. Option A reaches only 50% of steady state. Option B reaches 75%. Option D is
unnecessarily long.
Q9: A nurse practitioner is considering pharmacogenomic testing for a patient before prescribing clopidogrel.
Which genetic variation is most relevant to clopidogrel metabolism and clinical response?
A. CYP2C19 loss-of-function alleles, leading to reduced conversion of clopidogrel to its active metabolite and
increased cardiovascular risk [CORRECT]
B. CYP3A4 polymorphisms that increase clopidogrel activation
C. CYP2D6 ultra-rapid metabolizer status increasing active metabolite formation
D. UGT1A1 polymorphisms affecting clopidogrel glucuronidation
Correct Answer: A
Rationale: Clopidogrel is a prodrug requiring CYP2C19-mediated bioactivation to its active thiol metabolite. Patients with
CYP2C19 loss-of-function alleles (particularly CYP2C19*2 and *3, most common in Asian and Pacific Islander populations)
have significantly reduced conversion to the active metabolite, resulting in decreased platelet inhibition and higher rates of
cardiovascular events including stent thrombosis. The FDA includes a boxed warning recommending alternative antiplatelet
therapy (e.g., prasugrel, ticagrelor) in CYP2C19 poor metabolizers. Options B, C, and D describe enzyme systems not
primarily responsible for clopidogrel activation.
Q10: A 55-year-old patient with chronic kidney disease (CrCl 25 mL/min) is prescribed a renally cleared drug. The
nurse practitioner knows that which pharmacokinetic parameter is most directly affected by decreased renal
function?
NURS 6521 Advanced Pharmacology Final Exam Page 3
, A. First-pass metabolism
B. Volume of distribution
C. Total body clearance and elimination half-life [CORRECT]
D. Oral bioavailability
Correct Answer: C
Rationale: For drugs eliminated primarily by renal excretion (e.g., aminoglycosides, lithium, gabapentin, vancomycin),
decreased renal function directly reduces total body clearance. Reduced clearance prolongs elimination half-life (t1/2 = 0.693
x Vd / Clearance), leading to drug accumulation and increased toxicity risk. Dose adjustment based on creatinine clearance
is essential. Option A is hepatic, not renal. Option B may be affected indirectly but is not the primary concern. Option D is not
directly affected by renal function.
Q11: A patient taking phenytoin for seizure management presents with nystagmus, ataxia, and confusion. Serum
phenytoin level is 32 mcg/mL (therapeutic range 10-20 mcg/mL). Which pharmacokinetic property of phenytoin
best explains why a small dose increase caused a disproportionately large increase in serum concentration?
A. Phenytoin follows first-order kinetics at all concentration ranges
B. Phenytoin undergoes saturable (Michaelis-Menten) hepatic metabolism, where enzyme capacity becomes
maxed out at therapeutic concentrations [CORRECT]
C. Phenytoin has a very large volume of distribution that changes with dose
D. Phenytoin is primarily renally eliminated and accumulates when GFR decreases
Correct Answer: B
Rationale: Phenytoin undergoes capacity-limited (saturable) hepatic metabolism following Michaelis-Menten kinetics. At
concentrations below the enzyme's maximum capacity (Vmax), metabolism is approximately first-order. However, as
concentrations approach and exceed the Km value (approximately 4-5 mcg/mL), the metabolic enzymes become saturated,
and a small dose increase produces a disproportionate rise in serum concentration. This is why phenytoin requires
therapeutic drug monitoring and careful dose titration. Option A is incorrect; phenytoin is the classic example of nonlinear
kinetics. Option C is unrelated. Option D is incorrect because phenytoin is hepatically, not renally, eliminated.
Q12: A nurse practitioner is prescribing a medication for a patient who takes antacids containing magnesium and
aluminum hydroxide. The drug is a weak base with pH-dependent absorption. What is the most likely effect of the
antacid on this drug's absorption?
A. Increased absorption due to higher gastric pH favoring the unionized form
B. Decreased absorption due to increased gastric pH causing more of the drug to remain in the ionized,
non-absorbable form [CORRECT]
C. No effect because antacids do not alter gastric pH significantly
D. Increased metabolism of the drug in the stomach due to altered pH
Correct Answer: B
Rationale: Weak bases are preferentially absorbed in their unionized (lipophilic) form, which predominates at lower (acidic)
pH. Antacids raise gastric pH, shifting the equilibrium toward the ionized (hydrophilic) form of weak bases, which cannot
readily cross lipid membranes. This reduces absorption. Examples include ketoconazole, itraconazole, and fluoroquinolones.
The opposite effect occurs with weak acids (e.g., aspirin, penicillins), which are better absorbed in acidic environments.
Option A describes the effect of antacids on weak acids. Options C and D are incorrect.
Q13: A 70-year-old patient is started on a highly protein-bound drug (98% bound to albumin). The patient has
hypoalbuminemia (albumin 2.0 g/dL). What is the primary clinical concern in this situation?
A. Decreased drug effect due to less protein-bound drug available for distribution
B. Increased free (active) drug concentration leading to enhanced pharmacological effect and higher risk of toxicity
[CORRECT]
C. Accelerated renal excretion due to reduced protein binding
D. No significant clinical effect because protein binding has minimal clinical relevance
NURS 6521 Advanced Pharmacology Final Exam Page 4
FINAL EXAM
NURS 6521N Week 11 | Version A | 100 Questions with Correct Answers
Walden University | 2026-2027 Curriculum | A+ Grade Verified
Exam Format: Multiple Choice (4 options, A-D) Total Questions: 100
Cognitive Levels: 25% Recall, 50% Application, 25% Analysis Passing Standard: A+ Grade
Section 1: Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics (Q1-Q15)
Q1: A 45-year-old patient is prescribed a medication with high first-pass metabolism. The nurse practitioner
understands that which of the following best describes the consequence of first-pass metabolism on this drug?
A. The drug will have a prolonged half-life requiring less frequent dosing
B. A significant portion of the oral dose is metabolized before reaching systemic circulation, reducing bioavailability
[CORRECT]
C. The drug will be primarily excreted unchanged by the kidneys
D. First-pass metabolism increases the drug's volume of distribution
Correct Answer: B
Rationale: First-pass metabolism refers to the pre-systemic metabolism of a drug in the liver and/or intestinal wall before it
reaches the systemic circulation. Drugs with high first-pass metabolism (e.g., propranolol, morphine, verapamil) have
significantly reduced oral bioavailability, often requiring higher oral doses compared to parenteral administration. Options A,
C, and D are incorrect because first-pass metabolism does not directly determine half-life, renal excretion, or volume of
distribution.
Q2: A nurse practitioner is reviewing the pharmacokinetic profile of a new drug. The drug has a volume of
distribution (Vd) of 500 L in a 70-kg patient. What does this value most likely indicate about the drug's properties?
A. The drug is hydrophilic and remains primarily in the plasma compartment
B. The drug is extensively bound to plasma proteins
C. The drug is highly lipophilic and distributes widely into tissues, including adipose tissue [CORRECT]
D. The drug is confined to the extracellular fluid space
Correct Answer: C
Rationale: A Vd of 500 L in a 70-kg patient greatly exceeds total body water (approximately 42 L), indicating extensive tissue
distribution. This is characteristic of lipophilic drugs that readily cross cell membranes and accumulate in adipose tissue and
other body compartments. Drugs like digoxin (Vd ~500 L) and amiodarone (Vd ~70 L/kg) exemplify this pattern. Options A
and D would show Vd values approximating plasma volume (~3-5 L) or extracellular fluid (~12-15 L) respectively. Option B
describes protein binding, which reduces free drug available for distribution.
Q3: A patient with chronic liver disease is prescribed a medication that is a CYP3A4 substrate. The nurse
practitioner should anticipate which of the following pharmacokinetic changes?
A. Increased first-pass metabolism leading to decreased drug levels
B. Decreased hepatic clearance leading to increased drug plasma concentrations and potential toxicity
[CORRECT]
NURS 6521 Advanced Pharmacology Final Exam Page 1
, C. Enhanced renal excretion compensating for reduced hepatic metabolism
D. No significant change because CYP3A4 is not affected by liver disease
Correct Answer: B
Rationale: In chronic liver disease, hepatic blood flow decreases and CYP450 enzyme activity (including CYP3A4) is
impaired, particularly in cirrhosis. This results in decreased hepatic clearance of CYP3A4 substrates, leading to increased
plasma drug concentrations and higher risk of toxicity. The nurse practitioner should consider dose reduction and therapeutic
drug monitoring. Option A is incorrect because first-pass metabolism is reduced, not increased. Option C incorrectly
suggests renal compensation. Option D is false because liver disease significantly affects CYP3A4 activity.
Q4: A 30-year-old female patient of Asian descent is prescribed codeine for post-operative pain. Genetic testing
reveals she is a CYP2D6 ultra-rapid metabolizer. What clinical effect should the nurse practitioner anticipate?
A. Therapeutic analgesia with standard dosing due to efficient conversion to morphine
B. No analgesic effect because codeine cannot be converted to its active metabolite
C. Excessive morphine formation leading to respiratory depression and potential opioid toxicity even at standard
doses [CORRECT]
D. Prolonged codeine half-life due to impaired metabolism
Correct Answer: C
Rationale: Codeine is a prodrug that requires CYP2D6-mediated O-demethylation to morphine for analgesic effect.
Ultra-rapid CYP2D6 metabolizers convert codeine to morphine at an accelerated rate, producing dangerously high morphine
levels. This has led to fatal respiratory depression, particularly in pediatric patients. The FDA has issued a boxed warning
against codeine use in CYP2D6 ultra-rapid metabolizers and in children post-tonsillectomy. Option A underestimates the risk.
Option B describes poor metabolizers. Option D describes poor metabolizers, not ultra-rapid metabolizers.
Q5: A patient taking warfarin is started on amiodarone for atrial fibrillation. The nurse practitioner understands that
this drug interaction is primarily due to which mechanism?
A. Amiodarone induces CYP2C9, increasing warfarin metabolism and decreasing INR
B. Amiodarone inhibits CYP2C9, decreasing warfarin metabolism and increasing INR and bleeding risk
[CORRECT]
C. Amiodarone decreases warfarin protein binding, increasing free warfarin levels transiently
D. Amiodarone increases renal clearance of warfarin, reducing its anticoagulant effect
Correct Answer: B
Rationale: Amiodarone is a potent inhibitor of CYP2C9, the primary enzyme responsible for metabolizing S-warfarin (the
more potent enantiomer). Inhibition of CYP2C9 reduces warfarin clearance, leading to increased INR and elevated bleeding
risk. The warfarin dose should typically be reduced by 30-50% when amiodarone is initiated, with close INR monitoring. This
interaction can persist for weeks after amiodarone discontinuation due to its extremely long half-life. Option A incorrectly
describes induction. Options C and D describe mechanisms not relevant to this interaction.
Q6: A nurse practitioner is explaining pharmacodynamics to a nursing student. Which statement best describes
the concept of efficacy as it relates to drug-receptor interaction?
A. The ability of a drug to bind to a receptor
B. The concentration of drug required to produce 50% of the maximum effect
C. The maximum effect a drug can produce when all available receptors are occupied, regardless of dose
[CORRECT]
D. The rate at which a drug is eliminated from the body
Correct Answer: C
Rationale: Efficacy (Emax) refers to the maximum pharmacological effect a drug can produce when all available receptors
are occupied or the drug's intrinsic ability to activate a response. It is an important distinction from potency, which relates to
the dose needed to achieve a given effect. A drug with high efficacy is a full agonist, while a partial agonist has lower efficacy
NURS 6521 Advanced Pharmacology Final Exam Page 2
, even at full receptor occupancy. Option A describes affinity. Option B describes EC50 (potency). Option D describes
elimination, a pharmacokinetic concept.
Q7: A 60-year-old patient with a history of myocardial infarction is prescribed atenolol. The nurse practitioner
explains that atenolol is a cardioselective beta-1 blocker. Which clinical effect is most directly mediated by beta-1
receptor blockade?
A. Bronchodilation
B. Decreased heart rate and decreased cardiac output [CORRECT]
C. Vasodilation of skeletal muscle arterioles
D. Decreased glycogenolysis in skeletal muscle
Correct Answer: B
Rationale: Beta-1 receptors are primarily located in the heart (SA node, AV node, and ventricular myocardium). Blockade of
beta-1 receptors reduces heart rate (negative chronotropy), decreases conduction velocity through the AV node (negative
dromotropy), and reduces myocardial contractility (negative inotropy), collectively decreasing cardiac output. Atenolol is
considered cardioselective at low doses, making it preferred over nonselective beta-blockers in patients with mild respiratory
disease. Option A (bronchodilation) and Option C (vasodilation) are beta-2 effects. Option D is also a beta-2 mediated effect.
Q8: A patient is prescribed a drug with a half-life of 12 hours. Approximately how long will it take to reach
steady-state plasma concentrations with consistent dosing?
A. 12 hours
B. 24 hours
C. 48 to 60 hours (approximately 4-5 half-lives) [CORRECT]
D. 120 hours (approximately 10 half-lives)
Correct Answer: C
Rationale: Steady-state concentration is achieved when the rate of drug administration equals the rate of elimination. It takes
approximately 4-5 half-lives to reach approximately 94-97% of steady state. For a drug with a 12-hour half-life, steady state
would be reached in approximately 48-60 hours. This pharmacokinetic principle is fundamental for determining when to
assess drug efficacy and adjust doses. Option A reaches only 50% of steady state. Option B reaches 75%. Option D is
unnecessarily long.
Q9: A nurse practitioner is considering pharmacogenomic testing for a patient before prescribing clopidogrel.
Which genetic variation is most relevant to clopidogrel metabolism and clinical response?
A. CYP2C19 loss-of-function alleles, leading to reduced conversion of clopidogrel to its active metabolite and
increased cardiovascular risk [CORRECT]
B. CYP3A4 polymorphisms that increase clopidogrel activation
C. CYP2D6 ultra-rapid metabolizer status increasing active metabolite formation
D. UGT1A1 polymorphisms affecting clopidogrel glucuronidation
Correct Answer: A
Rationale: Clopidogrel is a prodrug requiring CYP2C19-mediated bioactivation to its active thiol metabolite. Patients with
CYP2C19 loss-of-function alleles (particularly CYP2C19*2 and *3, most common in Asian and Pacific Islander populations)
have significantly reduced conversion to the active metabolite, resulting in decreased platelet inhibition and higher rates of
cardiovascular events including stent thrombosis. The FDA includes a boxed warning recommending alternative antiplatelet
therapy (e.g., prasugrel, ticagrelor) in CYP2C19 poor metabolizers. Options B, C, and D describe enzyme systems not
primarily responsible for clopidogrel activation.
Q10: A 55-year-old patient with chronic kidney disease (CrCl 25 mL/min) is prescribed a renally cleared drug. The
nurse practitioner knows that which pharmacokinetic parameter is most directly affected by decreased renal
function?
NURS 6521 Advanced Pharmacology Final Exam Page 3
, A. First-pass metabolism
B. Volume of distribution
C. Total body clearance and elimination half-life [CORRECT]
D. Oral bioavailability
Correct Answer: C
Rationale: For drugs eliminated primarily by renal excretion (e.g., aminoglycosides, lithium, gabapentin, vancomycin),
decreased renal function directly reduces total body clearance. Reduced clearance prolongs elimination half-life (t1/2 = 0.693
x Vd / Clearance), leading to drug accumulation and increased toxicity risk. Dose adjustment based on creatinine clearance
is essential. Option A is hepatic, not renal. Option B may be affected indirectly but is not the primary concern. Option D is not
directly affected by renal function.
Q11: A patient taking phenytoin for seizure management presents with nystagmus, ataxia, and confusion. Serum
phenytoin level is 32 mcg/mL (therapeutic range 10-20 mcg/mL). Which pharmacokinetic property of phenytoin
best explains why a small dose increase caused a disproportionately large increase in serum concentration?
A. Phenytoin follows first-order kinetics at all concentration ranges
B. Phenytoin undergoes saturable (Michaelis-Menten) hepatic metabolism, where enzyme capacity becomes
maxed out at therapeutic concentrations [CORRECT]
C. Phenytoin has a very large volume of distribution that changes with dose
D. Phenytoin is primarily renally eliminated and accumulates when GFR decreases
Correct Answer: B
Rationale: Phenytoin undergoes capacity-limited (saturable) hepatic metabolism following Michaelis-Menten kinetics. At
concentrations below the enzyme's maximum capacity (Vmax), metabolism is approximately first-order. However, as
concentrations approach and exceed the Km value (approximately 4-5 mcg/mL), the metabolic enzymes become saturated,
and a small dose increase produces a disproportionate rise in serum concentration. This is why phenytoin requires
therapeutic drug monitoring and careful dose titration. Option A is incorrect; phenytoin is the classic example of nonlinear
kinetics. Option C is unrelated. Option D is incorrect because phenytoin is hepatically, not renally, eliminated.
Q12: A nurse practitioner is prescribing a medication for a patient who takes antacids containing magnesium and
aluminum hydroxide. The drug is a weak base with pH-dependent absorption. What is the most likely effect of the
antacid on this drug's absorption?
A. Increased absorption due to higher gastric pH favoring the unionized form
B. Decreased absorption due to increased gastric pH causing more of the drug to remain in the ionized,
non-absorbable form [CORRECT]
C. No effect because antacids do not alter gastric pH significantly
D. Increased metabolism of the drug in the stomach due to altered pH
Correct Answer: B
Rationale: Weak bases are preferentially absorbed in their unionized (lipophilic) form, which predominates at lower (acidic)
pH. Antacids raise gastric pH, shifting the equilibrium toward the ionized (hydrophilic) form of weak bases, which cannot
readily cross lipid membranes. This reduces absorption. Examples include ketoconazole, itraconazole, and fluoroquinolones.
The opposite effect occurs with weak acids (e.g., aspirin, penicillins), which are better absorbed in acidic environments.
Option A describes the effect of antacids on weak acids. Options C and D are incorrect.
Q13: A 70-year-old patient is started on a highly protein-bound drug (98% bound to albumin). The patient has
hypoalbuminemia (albumin 2.0 g/dL). What is the primary clinical concern in this situation?
A. Decreased drug effect due to less protein-bound drug available for distribution
B. Increased free (active) drug concentration leading to enhanced pharmacological effect and higher risk of toxicity
[CORRECT]
C. Accelerated renal excretion due to reduced protein binding
D. No significant clinical effect because protein binding has minimal clinical relevance
NURS 6521 Advanced Pharmacology Final Exam Page 4
