NU 641 Advanced Clinical Pharmacology Final Exam Questions
and Answers| Updated| Pass Guaranteed| Regis
1. A drug with a high hepatic extraction ratio given orally will most likely have:
A. Increased bioavailability compared with IV dosing
B. Complete excretion unchanged in feces
C. Reduced oral bioavailability because of first-pass metabolism
D. No effect from liver disease
Answer: C. Reduced oral bioavailability because of first-pass metabolism
Rationale: High-extraction drugs (e.g., propranolol, lidocaine, morphine) are
extensively cleared by the liver before reaching systemic circulation. Oral
doses are therefore larger than IV doses, and liver disease or portosystemic
shunting can sharply raise bioavailability.
2. Administering ciprofloxacin with calcium-fortified juice or an
aluminum/magnesium antacid is a problem because:
A. Divalent and trivalent cations chelate the drug and decrease absorption
B. They induce CYP3A4
C. They increase renal clearance
D. They increase gastric emptying
Answer: A. Divalent and trivalent cations chelate the drug and decrease
absorption
Rationale: Fluoroquinolones, tetracyclines, and integrase inhibitors bind
polyvalent cations in the gut, forming insoluble complexes. Separate dosing by
several hours as directed by the product labeling.
Page 1
,3. A drug has a volume of distribution of 100 L and the target plasma
concentration is 2 mg/L. What IV loading dose is needed?
A. 50 mg
B. 100 mg
C. 400 mg
D. 200 mg
Answer: D. 200 mg
Rationale: Loading dose = Vd x target concentration = 100 L x 2 mg/L = 200 mg
(assuming 100% bioavailability for IV).
4. If a patient's drug clearance is reduced by half and volume of distribution is
unchanged, the elimination half-life will:
A. Be cut in half
B. Approximately double
C. Remain the same
D. Become zero
Answer: B. Approximately double
Rationale: t1/2 = 0.693 x Vd / CL. Halving clearance doubles the half-life,
prolonging time to steady state and requiring a lower maintenance dose.
5. Carbamazepine serum concentrations often fall during the first weeks of
therapy because of:
A. Increased protein binding
B. Autoinduction of its own CYP3A4 metabolism
C. Decreased renal excretion
D. Delayed gastric emptying
Answer: B. Autoinduction of its own CYP3A4 metabolism
Rationale: Carbamazepine induces CYP3A4 (and other enzymes), accelerating
its own metabolism and that of many other drugs (e.g., oral contraceptives,
warfarin). Dose titration and level monitoring are needed.
Page 2
,6. Grapefruit juice increases the effect of felodipine and simvastatin by:
A. Inducing hepatic CYP2D6
B. Increasing renal tubular secretion
C. Blocking P-glycoprotein in the kidney to decrease absorption
D. Inhibiting intestinal CYP3A4 and increasing oral bioavailability
Answer: D. Inhibiting intestinal CYP3A4 and increasing oral bioavailability
Rationale: Components of grapefruit irreversibly inhibit gut-wall CYP3A4,
decreasing first-pass metabolism of susceptible substrates and raising systemic
exposure.
7. A patient who is a CYP2C19 poor metabolizer is prescribed clopidogrel. The
expected consequence is:
A. Reduced antiplatelet effect because the prodrug is not activated
B. Enhanced antiplatelet effect
C. Increased risk of hypoglycemia
D. No clinically significant difference
Answer: A. Reduced antiplatelet effect because the prodrug is not activated
Rationale: Clopidogrel is a prodrug requiring CYP2C19 bioactivation. Poor
metabolizers have higher rates of cardiovascular events, and an alternative
P2Y12 inhibitor (e.g., ticagrelor) may be chosen.
8. Probenecid is sometimes given with penicillin to prolong its action. The
mechanism is:
A. Induction of hepatic metabolism
B. Increased glomerular filtration
C. Inhibition of renal tubular secretion of penicillin
D. Inhibition of bacterial beta-lactamase
Answer: C. Inhibition of renal tubular secretion of penicillin
Rationale: Probenecid blocks organic anion transporters in the proximal tubule,
reducing penicillin elimination and raising serum levels.
Page 3
, 9. When should a trough drug concentration typically be drawn?
A. One hour after the dose
B. At the time of peak absorption
C. Immediately before the next scheduled dose
D. Any time during the day
Answer: C. Immediately before the next scheduled dose
Rationale: The trough is the lowest concentration in the dosing interval and
reflects the minimum effective level. Peak levels are drawn after distribution is
complete (e.g., 30 minutes after an aminoglycoside infusion ends).
10. Loss of antianginal effect with continuous nitroglycerin patch use is best
avoided by:
A. Providing a nitrate-free interval of about 10-14 hours daily
B. Doubling the dose each week
C. Adding a second nitrate
D. Stopping all other antianginals
Answer: A. Providing a nitrate-free interval of about 10-14 hours daily
Rationale: Continuous nitrate exposure causes tolerance (tachyphylaxis)
through depletion of sulfhydryl groups and neurohormonal activation. A daily
nitrate-free period restores responsiveness.
11. A drug with a larger therapeutic index (TD50/ED50) is generally:
A. More potent
B. More lipid soluble
C. More likely to require level monitoring
D. Safer, with a wider margin between effective and toxic doses
Answer: D. Safer, with a wider margin between effective and toxic doses
Rationale: A high therapeutic index means toxicity occurs at doses far above
the effective dose. Narrow-index drugs (e.g., lithium, warfarin, digoxin) require
monitoring.
Page 4
and Answers| Updated| Pass Guaranteed| Regis
1. A drug with a high hepatic extraction ratio given orally will most likely have:
A. Increased bioavailability compared with IV dosing
B. Complete excretion unchanged in feces
C. Reduced oral bioavailability because of first-pass metabolism
D. No effect from liver disease
Answer: C. Reduced oral bioavailability because of first-pass metabolism
Rationale: High-extraction drugs (e.g., propranolol, lidocaine, morphine) are
extensively cleared by the liver before reaching systemic circulation. Oral
doses are therefore larger than IV doses, and liver disease or portosystemic
shunting can sharply raise bioavailability.
2. Administering ciprofloxacin with calcium-fortified juice or an
aluminum/magnesium antacid is a problem because:
A. Divalent and trivalent cations chelate the drug and decrease absorption
B. They induce CYP3A4
C. They increase renal clearance
D. They increase gastric emptying
Answer: A. Divalent and trivalent cations chelate the drug and decrease
absorption
Rationale: Fluoroquinolones, tetracyclines, and integrase inhibitors bind
polyvalent cations in the gut, forming insoluble complexes. Separate dosing by
several hours as directed by the product labeling.
Page 1
,3. A drug has a volume of distribution of 100 L and the target plasma
concentration is 2 mg/L. What IV loading dose is needed?
A. 50 mg
B. 100 mg
C. 400 mg
D. 200 mg
Answer: D. 200 mg
Rationale: Loading dose = Vd x target concentration = 100 L x 2 mg/L = 200 mg
(assuming 100% bioavailability for IV).
4. If a patient's drug clearance is reduced by half and volume of distribution is
unchanged, the elimination half-life will:
A. Be cut in half
B. Approximately double
C. Remain the same
D. Become zero
Answer: B. Approximately double
Rationale: t1/2 = 0.693 x Vd / CL. Halving clearance doubles the half-life,
prolonging time to steady state and requiring a lower maintenance dose.
5. Carbamazepine serum concentrations often fall during the first weeks of
therapy because of:
A. Increased protein binding
B. Autoinduction of its own CYP3A4 metabolism
C. Decreased renal excretion
D. Delayed gastric emptying
Answer: B. Autoinduction of its own CYP3A4 metabolism
Rationale: Carbamazepine induces CYP3A4 (and other enzymes), accelerating
its own metabolism and that of many other drugs (e.g., oral contraceptives,
warfarin). Dose titration and level monitoring are needed.
Page 2
,6. Grapefruit juice increases the effect of felodipine and simvastatin by:
A. Inducing hepatic CYP2D6
B. Increasing renal tubular secretion
C. Blocking P-glycoprotein in the kidney to decrease absorption
D. Inhibiting intestinal CYP3A4 and increasing oral bioavailability
Answer: D. Inhibiting intestinal CYP3A4 and increasing oral bioavailability
Rationale: Components of grapefruit irreversibly inhibit gut-wall CYP3A4,
decreasing first-pass metabolism of susceptible substrates and raising systemic
exposure.
7. A patient who is a CYP2C19 poor metabolizer is prescribed clopidogrel. The
expected consequence is:
A. Reduced antiplatelet effect because the prodrug is not activated
B. Enhanced antiplatelet effect
C. Increased risk of hypoglycemia
D. No clinically significant difference
Answer: A. Reduced antiplatelet effect because the prodrug is not activated
Rationale: Clopidogrel is a prodrug requiring CYP2C19 bioactivation. Poor
metabolizers have higher rates of cardiovascular events, and an alternative
P2Y12 inhibitor (e.g., ticagrelor) may be chosen.
8. Probenecid is sometimes given with penicillin to prolong its action. The
mechanism is:
A. Induction of hepatic metabolism
B. Increased glomerular filtration
C. Inhibition of renal tubular secretion of penicillin
D. Inhibition of bacterial beta-lactamase
Answer: C. Inhibition of renal tubular secretion of penicillin
Rationale: Probenecid blocks organic anion transporters in the proximal tubule,
reducing penicillin elimination and raising serum levels.
Page 3
, 9. When should a trough drug concentration typically be drawn?
A. One hour after the dose
B. At the time of peak absorption
C. Immediately before the next scheduled dose
D. Any time during the day
Answer: C. Immediately before the next scheduled dose
Rationale: The trough is the lowest concentration in the dosing interval and
reflects the minimum effective level. Peak levels are drawn after distribution is
complete (e.g., 30 minutes after an aminoglycoside infusion ends).
10. Loss of antianginal effect with continuous nitroglycerin patch use is best
avoided by:
A. Providing a nitrate-free interval of about 10-14 hours daily
B. Doubling the dose each week
C. Adding a second nitrate
D. Stopping all other antianginals
Answer: A. Providing a nitrate-free interval of about 10-14 hours daily
Rationale: Continuous nitrate exposure causes tolerance (tachyphylaxis)
through depletion of sulfhydryl groups and neurohormonal activation. A daily
nitrate-free period restores responsiveness.
11. A drug with a larger therapeutic index (TD50/ED50) is generally:
A. More potent
B. More lipid soluble
C. More likely to require level monitoring
D. Safer, with a wider margin between effective and toxic doses
Answer: D. Safer, with a wider margin between effective and toxic doses
Rationale: A high therapeutic index means toxicity occurs at doses far above
the effective dose. Narrow-index drugs (e.g., lithium, warfarin, digoxin) require
monitoring.
Page 4
