Chamberlain NR 565 Advanced Pharmacology - Midterm Exam V3
1. Bioavailability refers to:
A. The fraction of the drug bound to plasma proteins
B. The time required to reach peak concentration
C. The fraction of the dose excreted in urine
D. The fraction of an administered dose that reaches the systemic circulation
unchanged
Correct Answer: D. The fraction of an administered dose that reaches the
systemic circulation unchanged
Rationale: Bioavailability is 100 percent for IV drugs and is reduced for oral drugs
by incomplete absorption and first-pass metabolism.
2. Which parameter primarily determines the size of a loading dose?
A. Clearance
B. Half-life
C. Volume of distribution
D. Protein binding of metabolites
Correct Answer: C. Volume of distribution
Rationale: Loading dose = target concentration x volume of distribution.
Maintenance dose depends on clearance.
3. Which parameter primarily determines the maintenance dose of a drug?
A. Volume of distribution
B. Clearance
C. Time to peak
D. Potency
Correct Answer: B. Clearance
Rationale: The maintenance dosing rate must equal the rate of elimination
(clearance x target concentration) to keep steady state.
,4. A patient with renal impairment takes a renally cleared drug. Assuming
volume of distribution is unchanged, what happens to the drug's half-life?
A. It decreases
B. It increases
C. It is unchanged
D. It becomes zero-order
Correct Answer: B. It increases
Rationale: Half-life = 0.693 x volume of distribution / clearance. Reduced clearance
prolongs half-life and increases accumulation.
5. Which drug has a narrow therapeutic index?
A. Amoxicillin
B. Digoxin
C. Loratadine
D. Omeprazole
Correct Answer: B. Digoxin
Rationale: Small differences between therapeutic and toxic concentrations require
monitoring. Others include warfarin, lithium, phenytoin, theophylline and
aminoglycosides.
6. A competitive antagonist has what effect on the dose-response curve of an
agonist?
A. Shifts the curve to the right without changing maximal effect
B. Shifts the curve to the left
C. Reduces the maximal effect and leaves potency unchanged
D. Has no effect
Correct Answer: A. Shifts the curve to the right without changing maximal
effect
Rationale: Competitive antagonism is surmountable with higher agonist
concentrations, so Emax is unchanged but potency appears reduced.
,7. A partial agonist differs from a full agonist because it:
A. Has no affinity for the receptor
B. Irreversibly binds the receptor
C. Produces a submaximal response even at full receptor occupancy
D. Produces a greater maximal response
Correct Answer: C. Produces a submaximal response even at full receptor
occupancy
Rationale: Partial agonists have lower intrinsic activity and may act as antagonists
in the presence of a full agonist (e.g., buprenorphine).
8. A rapid decrease in drug response after only a few doses is called:
A. Idiosyncrasy
B. Tachyphylaxis
C. Synergism
D. Dependence
Correct Answer: B. Tachyphylaxis
Rationale: Tachyphylaxis is acute tolerance, such as with nasal decongestants or
nitrates. Tolerance develops more gradually.
9. Phase II drug metabolism primarily involves:
A. Oxidation by CYP enzymes
B. Conjugation (e.g., glucuronidation) to form water-soluble metabolites
C. Renal tubular secretion
D. Enterohepatic recirculation only
Correct Answer: B. Conjugation (e.g., glucuronidation) to form water-soluble
metabolites
Rationale: Phase I reactions are oxidation, reduction and hydrolysis (mostly CYP).
Phase II conjugation makes drugs more polar for excretion.
, 10. A patient on warfarin starts rifampin. What is the expected effect?
A. Decreased INR from enzyme induction
B. Increased INR
C. No change in INR
D. Immediate hemorrhage
Correct Answer: A. Decreased INR from enzyme induction
Rationale: Rifampin induces CYP2C9, 3A4 and 1A2, accelerating warfarin
metabolism. Monitor INR and adjust the dose.
11. A patient on simvastatin is prescribed clarithromycin. What is the greatest
concern?
A. Reduced statin efficacy
B. Hepatic enzyme induction
C. Rhabdomyolysis from increased statin levels
D. Hypoglycemia
Correct Answer: C. Rhabdomyolysis from increased statin levels
Rationale: Clarithromycin inhibits CYP3A4, greatly increasing simvastatin exposure.
Hold the statin or choose azithromycin.
12. Clopidogrel is a prodrug. Which patients have reduced antiplatelet effect?
A. CYP2D6 ultra-rapid metabolizers
B. Patients with high albumin
C. CYP2C19 poor metabolizers
D. Patients on a high-vitamin K diet
Correct Answer: C. CYP2C19 poor metabolizers
Rationale: Clopidogrel requires CYP2C19 activation. Omeprazole and
esomeprazole also inhibit activation; pantoprazole is preferred.
1. Bioavailability refers to:
A. The fraction of the drug bound to plasma proteins
B. The time required to reach peak concentration
C. The fraction of the dose excreted in urine
D. The fraction of an administered dose that reaches the systemic circulation
unchanged
Correct Answer: D. The fraction of an administered dose that reaches the
systemic circulation unchanged
Rationale: Bioavailability is 100 percent for IV drugs and is reduced for oral drugs
by incomplete absorption and first-pass metabolism.
2. Which parameter primarily determines the size of a loading dose?
A. Clearance
B. Half-life
C. Volume of distribution
D. Protein binding of metabolites
Correct Answer: C. Volume of distribution
Rationale: Loading dose = target concentration x volume of distribution.
Maintenance dose depends on clearance.
3. Which parameter primarily determines the maintenance dose of a drug?
A. Volume of distribution
B. Clearance
C. Time to peak
D. Potency
Correct Answer: B. Clearance
Rationale: The maintenance dosing rate must equal the rate of elimination
(clearance x target concentration) to keep steady state.
,4. A patient with renal impairment takes a renally cleared drug. Assuming
volume of distribution is unchanged, what happens to the drug's half-life?
A. It decreases
B. It increases
C. It is unchanged
D. It becomes zero-order
Correct Answer: B. It increases
Rationale: Half-life = 0.693 x volume of distribution / clearance. Reduced clearance
prolongs half-life and increases accumulation.
5. Which drug has a narrow therapeutic index?
A. Amoxicillin
B. Digoxin
C. Loratadine
D. Omeprazole
Correct Answer: B. Digoxin
Rationale: Small differences between therapeutic and toxic concentrations require
monitoring. Others include warfarin, lithium, phenytoin, theophylline and
aminoglycosides.
6. A competitive antagonist has what effect on the dose-response curve of an
agonist?
A. Shifts the curve to the right without changing maximal effect
B. Shifts the curve to the left
C. Reduces the maximal effect and leaves potency unchanged
D. Has no effect
Correct Answer: A. Shifts the curve to the right without changing maximal
effect
Rationale: Competitive antagonism is surmountable with higher agonist
concentrations, so Emax is unchanged but potency appears reduced.
,7. A partial agonist differs from a full agonist because it:
A. Has no affinity for the receptor
B. Irreversibly binds the receptor
C. Produces a submaximal response even at full receptor occupancy
D. Produces a greater maximal response
Correct Answer: C. Produces a submaximal response even at full receptor
occupancy
Rationale: Partial agonists have lower intrinsic activity and may act as antagonists
in the presence of a full agonist (e.g., buprenorphine).
8. A rapid decrease in drug response after only a few doses is called:
A. Idiosyncrasy
B. Tachyphylaxis
C. Synergism
D. Dependence
Correct Answer: B. Tachyphylaxis
Rationale: Tachyphylaxis is acute tolerance, such as with nasal decongestants or
nitrates. Tolerance develops more gradually.
9. Phase II drug metabolism primarily involves:
A. Oxidation by CYP enzymes
B. Conjugation (e.g., glucuronidation) to form water-soluble metabolites
C. Renal tubular secretion
D. Enterohepatic recirculation only
Correct Answer: B. Conjugation (e.g., glucuronidation) to form water-soluble
metabolites
Rationale: Phase I reactions are oxidation, reduction and hydrolysis (mostly CYP).
Phase II conjugation makes drugs more polar for excretion.
, 10. A patient on warfarin starts rifampin. What is the expected effect?
A. Decreased INR from enzyme induction
B. Increased INR
C. No change in INR
D. Immediate hemorrhage
Correct Answer: A. Decreased INR from enzyme induction
Rationale: Rifampin induces CYP2C9, 3A4 and 1A2, accelerating warfarin
metabolism. Monitor INR and adjust the dose.
11. A patient on simvastatin is prescribed clarithromycin. What is the greatest
concern?
A. Reduced statin efficacy
B. Hepatic enzyme induction
C. Rhabdomyolysis from increased statin levels
D. Hypoglycemia
Correct Answer: C. Rhabdomyolysis from increased statin levels
Rationale: Clarithromycin inhibits CYP3A4, greatly increasing simvastatin exposure.
Hold the statin or choose azithromycin.
12. Clopidogrel is a prodrug. Which patients have reduced antiplatelet effect?
A. CYP2D6 ultra-rapid metabolizers
B. Patients with high albumin
C. CYP2C19 poor metabolizers
D. Patients on a high-vitamin K diet
Correct Answer: C. CYP2C19 poor metabolizers
Rationale: Clopidogrel requires CYP2C19 activation. Omeprazole and
esomeprazole also inhibit activation; pantoprazole is preferred.
