NU553 Unit 1: Principles of Therapeutics Exam 1 –
Advanced Pharmacology and Pharmacotherapeutics | High-
Yield Review with Verified Questions, Correct Answers &
Detailed Rationales | 2026 PDF Download
Category Key Topics
Pharmacokinetics ADME, half-life, bioavailability, Vd, first-pass, CYP450
Potency vs. efficacy, receptor types, agonists/antagonists,
Pharmacodynamics
EC50
Pediatrics, neonates, geriatrics, pregnancy, lactation, CKD,
Special Populations
liver disease
CYP inhibitors/inducers, protein binding,
Drug Interactions
additive/synergistic/antagonistic
Adverse Effects ADRs Type A/B, toxicity, teratogenicity, BEERS CRITERIA
Therapeutic
TDM, NTI drugs (digoxin, warfarin, lithium, phenytoin)
Monitoring
Pharmacogenomics CYP2D6, CYP2C19, VKORC1, HLA-B1502
Question 1
A patient is prescribed a medication with a narrow therapeutic index. Which
nursing action is most appropriate?
A. Administer the medication without monitoring serum levels
B. Monitor serum drug levels regularly and assess for signs of toxicity
C. Increase the dose gradually to achieve therapeutic effect
D. Avoid monitoring since the drug is safe at standard doses
Correct Answer: B
Rationale: Medications with a narrow therapeutic index (NTI) have a small
difference between therapeutic and toxic doses. Regular monitoring of serum drug
levels is essential to ensure the drug remains within the therapeutic range and to
prevent toxicity. Examples include warfarin, lithium, digoxin, and phenytoin.
,Option A is dangerous, Option C could lead to toxicity, and Option D is incorrect
because NTI drugs require careful monitoring.
Question 2
Which phase of pharmacokinetics is most affected when a patient has liver
disease?
A. Absorption
B. Distribution
C. Metabolism
D. Excretion
Correct Answer: C
Rationale: The liver is the primary site of drug metabolism through the CYP450
enzyme system. In liver disease, metabolic capacity is reduced, leading to
decreased drug clearance, increased serum drug levels, and potential toxicity.
Absorption occurs mainly in the GI tract, distribution involves blood transport and
tissue binding, and excretion is primarily renal (kidneys).
Question 3
A geriatric patient is receiving multiple medications. Which factor most
contributes to increased risk of adverse drug reactions in this population?
A. Increased gastric acid production
B. Decreased renal function and polypharmacy
C. Enhanced hepatic metabolism
D. Increased total body water
Correct Answer: B
Rationale: Geriatric patients experience age-related decreases in renal function
(reduced glomerular filtration rate), decreased hepatic metabolism, and altered
body composition (decreased total body water, increased fat). Polypharmacy
(taking multiple medications) increases the risk of drug-drug interactions. These
factors combined significantly increase adverse drug reaction risk. Options A, C,
and D are incorrect as geriatric patients typically have decreased gastric acid,
decreased metabolism, and decreased body water.
,Question 4
Which statement best describes the difference between potency and efficacy?
A. Potency refers to the maximum effect a drug can produce; efficacy refers to the
dose needed
B. Potency is the dose required to produce 50% of maximum effect; efficacy is the
maximum therapeutic effect achievable
C. Potency and efficacy are interchangeable terms
D. Efficacy refers to how quickly a drug works; potency refers to duration
Correct Answer: B
Rationale: Potency is the amount of drug needed to produce a specific effect
(typically measured as EC50 - dose producing 50% of maximum effect). A more
potent drug requires a lower dose. Efficacy is the maximum therapeutic effect a
drug can produce regardless of dose. A drug can be highly potent (needs low dose)
but have low efficacy (limited maximum effect). This is a critical concept in
pharmacodynamics.
Question 5
A pregnant patient in week 10 of gestation asks about medication safety. Which
trimester is most critical for teratogenic effects?
A. First trimester (weeks 1-12)
B. Second trimester (weeks 13-26)
C. Third trimester (weeks 27-40)
D. All trimesters are equally critical
Correct Answer: A
Rationale: The first trimester is the most critical period for teratogenicity
because organogenesis (organ formation) occurs during weeks 3-8. Exposure to
teratogens during this period can cause major structural abnormalities. The second
and third trimesters are more associated with functional development and growth.
However, medications should be avoided throughout pregnancy unless clearly
necessary.
, Question 6
Which CYP450 enzyme is most responsible for metabolizing approximately 50%
of all clinically used drugs?
A. CYP1A2
B. CYP2D6
C. CYP3A4
D. CYP2C9
Correct Answer: C
Rationale: CYP3A4 is the most abundant CYP450 enzyme in the liver and
metabolizes approximately 50% of all clinically used drugs, including statins,
calcium channel blockers, immunosuppressants, and many others. CYP2D6
metabolizes ~25% of drugs (including beta-blockers and antidepressants),
CYP2C9 metabolizes ~15% (including warfarin), and CYP1A2 metabolizes a
smaller percentage.
Question 7
A patient taking warfarin is also prescribed sulfamethoxazole-trimethoprol for
UTI. What is the expected outcome?
A. Decreased warfarin effect and increased clotting risk
B. Increased warfarin effect and increased bleeding risk
C. No change in warfarin effect
D. Decreased antibiotic effectiveness
Correct Answer: B
Rationale: Trimethoprol-sulfamethoxazole is a CYP450 inhibitor that inhibits the
metabolism of warfarin (metabolized by CYP2C9). This leads to increased
warfarin serum levels, increased anticoagulant effect, and elevated bleeding risk.
The patient's INR should be monitored closely, and warfarin dose may need
adjustment. This is a classic and clinically significant drug interaction.
Question 8
Which route of administration provides the most rapid drug absorption?
Advanced Pharmacology and Pharmacotherapeutics | High-
Yield Review with Verified Questions, Correct Answers &
Detailed Rationales | 2026 PDF Download
Category Key Topics
Pharmacokinetics ADME, half-life, bioavailability, Vd, first-pass, CYP450
Potency vs. efficacy, receptor types, agonists/antagonists,
Pharmacodynamics
EC50
Pediatrics, neonates, geriatrics, pregnancy, lactation, CKD,
Special Populations
liver disease
CYP inhibitors/inducers, protein binding,
Drug Interactions
additive/synergistic/antagonistic
Adverse Effects ADRs Type A/B, toxicity, teratogenicity, BEERS CRITERIA
Therapeutic
TDM, NTI drugs (digoxin, warfarin, lithium, phenytoin)
Monitoring
Pharmacogenomics CYP2D6, CYP2C19, VKORC1, HLA-B1502
Question 1
A patient is prescribed a medication with a narrow therapeutic index. Which
nursing action is most appropriate?
A. Administer the medication without monitoring serum levels
B. Monitor serum drug levels regularly and assess for signs of toxicity
C. Increase the dose gradually to achieve therapeutic effect
D. Avoid monitoring since the drug is safe at standard doses
Correct Answer: B
Rationale: Medications with a narrow therapeutic index (NTI) have a small
difference between therapeutic and toxic doses. Regular monitoring of serum drug
levels is essential to ensure the drug remains within the therapeutic range and to
prevent toxicity. Examples include warfarin, lithium, digoxin, and phenytoin.
,Option A is dangerous, Option C could lead to toxicity, and Option D is incorrect
because NTI drugs require careful monitoring.
Question 2
Which phase of pharmacokinetics is most affected when a patient has liver
disease?
A. Absorption
B. Distribution
C. Metabolism
D. Excretion
Correct Answer: C
Rationale: The liver is the primary site of drug metabolism through the CYP450
enzyme system. In liver disease, metabolic capacity is reduced, leading to
decreased drug clearance, increased serum drug levels, and potential toxicity.
Absorption occurs mainly in the GI tract, distribution involves blood transport and
tissue binding, and excretion is primarily renal (kidneys).
Question 3
A geriatric patient is receiving multiple medications. Which factor most
contributes to increased risk of adverse drug reactions in this population?
A. Increased gastric acid production
B. Decreased renal function and polypharmacy
C. Enhanced hepatic metabolism
D. Increased total body water
Correct Answer: B
Rationale: Geriatric patients experience age-related decreases in renal function
(reduced glomerular filtration rate), decreased hepatic metabolism, and altered
body composition (decreased total body water, increased fat). Polypharmacy
(taking multiple medications) increases the risk of drug-drug interactions. These
factors combined significantly increase adverse drug reaction risk. Options A, C,
and D are incorrect as geriatric patients typically have decreased gastric acid,
decreased metabolism, and decreased body water.
,Question 4
Which statement best describes the difference between potency and efficacy?
A. Potency refers to the maximum effect a drug can produce; efficacy refers to the
dose needed
B. Potency is the dose required to produce 50% of maximum effect; efficacy is the
maximum therapeutic effect achievable
C. Potency and efficacy are interchangeable terms
D. Efficacy refers to how quickly a drug works; potency refers to duration
Correct Answer: B
Rationale: Potency is the amount of drug needed to produce a specific effect
(typically measured as EC50 - dose producing 50% of maximum effect). A more
potent drug requires a lower dose. Efficacy is the maximum therapeutic effect a
drug can produce regardless of dose. A drug can be highly potent (needs low dose)
but have low efficacy (limited maximum effect). This is a critical concept in
pharmacodynamics.
Question 5
A pregnant patient in week 10 of gestation asks about medication safety. Which
trimester is most critical for teratogenic effects?
A. First trimester (weeks 1-12)
B. Second trimester (weeks 13-26)
C. Third trimester (weeks 27-40)
D. All trimesters are equally critical
Correct Answer: A
Rationale: The first trimester is the most critical period for teratogenicity
because organogenesis (organ formation) occurs during weeks 3-8. Exposure to
teratogens during this period can cause major structural abnormalities. The second
and third trimesters are more associated with functional development and growth.
However, medications should be avoided throughout pregnancy unless clearly
necessary.
, Question 6
Which CYP450 enzyme is most responsible for metabolizing approximately 50%
of all clinically used drugs?
A. CYP1A2
B. CYP2D6
C. CYP3A4
D. CYP2C9
Correct Answer: C
Rationale: CYP3A4 is the most abundant CYP450 enzyme in the liver and
metabolizes approximately 50% of all clinically used drugs, including statins,
calcium channel blockers, immunosuppressants, and many others. CYP2D6
metabolizes ~25% of drugs (including beta-blockers and antidepressants),
CYP2C9 metabolizes ~15% (including warfarin), and CYP1A2 metabolizes a
smaller percentage.
Question 7
A patient taking warfarin is also prescribed sulfamethoxazole-trimethoprol for
UTI. What is the expected outcome?
A. Decreased warfarin effect and increased clotting risk
B. Increased warfarin effect and increased bleeding risk
C. No change in warfarin effect
D. Decreased antibiotic effectiveness
Correct Answer: B
Rationale: Trimethoprol-sulfamethoxazole is a CYP450 inhibitor that inhibits the
metabolism of warfarin (metabolized by CYP2C9). This leads to increased
warfarin serum levels, increased anticoagulant effect, and elevated bleeding risk.
The patient's INR should be monitored closely, and warfarin dose may need
adjustment. This is a classic and clinically significant drug interaction.
Question 8
Which route of administration provides the most rapid drug absorption?
