NU 578 Unit 1 Exam (PDF) | Updated Exam
Questions | University of South Alabama
1. A patient with severe liver disease is prescribed a
medication that undergoes extensive first-pass
metabolism. The prescriber should anticipate:
A. Decreased oral bioavailability
B. Increased oral bioavailability
C. No change in bioavailability
D. Increased renal excretion
Correct Answer: B
Rationale: First-pass metabolism occurs in the liver. Liver
disease reduces hepatic extraction, so more drug reaches
systemic circulation, resulting in increased oral
bioavailability.
2. A drug has a volume of distribution (Vd) of 0.2 L/kg.
This suggests the drug is primarily:
A. Confined to plasma
1
,B. Distributed into total body water
C. Accumulated in fat tissue
D. Bound extensively to tissues
Correct Answer: A
Rationale: Vd of 0.05–0.2 L/kg indicates the drug
remains in plasma. Total body water Vd is ~0.5 L/kg.
High tissue binding would increase Vd.
3. Which CYP450 enzyme is most commonly involved in
clinically significant drug-drug interactions?
A. CYP2D6
B. CYP3A4
C. CYP1A2
D. CYP2C9
Correct Answer: B
Rationale: CYP3A4 metabolizes approximately 50% of
marketed drugs and is inhibited/induced by many agents
(e.g., grapefruit juice, rifampin, ketoconazole).
2
,4. A patient on digoxin starts clarithromycin. The digoxin
level rises to toxic levels. This is likely due to:
A. Inhibition of CYP3A4
B. Induction of P-glycoprotein
C. Inhibition of P-glycoprotein
D. Competition for albumin binding
Correct Answer: C
Rationale: Clarithromycin inhibits P-glycoprotein (P-gp) in
the gut and kidney, increasing digoxin absorption and
decreasing renal secretion. Digoxin is not significantly
metabolized by CYP450.
5. Which route of administration completely bypasses
first-pass metabolism?
A. Oral
B. Sublingual
3
, C. Rectal
D. Subcutaneous
Correct Answer: B
Rationale: Sublingual and IV routes avoid first-pass
metabolism entirely. Rectal bypasses ~50% but not
complete. Subcutaneous requires absorption but avoids
portal circulation; however, "completely bypasses" is best
answered by sublingual/IV.
6. A drug's half-life is 12 hours. Approximately how many
hours to reach steady state?
A. 24 hours
B. 36 hours
C. 48 hours
D. 60 hours
Correct Answer: D
Rationale: Steady state is reached in 4–5 half-lives. 5 ×
12 = 60 hours. 4 × 12 = 48 hours (93.75% steady state),
4
Questions | University of South Alabama
1. A patient with severe liver disease is prescribed a
medication that undergoes extensive first-pass
metabolism. The prescriber should anticipate:
A. Decreased oral bioavailability
B. Increased oral bioavailability
C. No change in bioavailability
D. Increased renal excretion
Correct Answer: B
Rationale: First-pass metabolism occurs in the liver. Liver
disease reduces hepatic extraction, so more drug reaches
systemic circulation, resulting in increased oral
bioavailability.
2. A drug has a volume of distribution (Vd) of 0.2 L/kg.
This suggests the drug is primarily:
A. Confined to plasma
1
,B. Distributed into total body water
C. Accumulated in fat tissue
D. Bound extensively to tissues
Correct Answer: A
Rationale: Vd of 0.05–0.2 L/kg indicates the drug
remains in plasma. Total body water Vd is ~0.5 L/kg.
High tissue binding would increase Vd.
3. Which CYP450 enzyme is most commonly involved in
clinically significant drug-drug interactions?
A. CYP2D6
B. CYP3A4
C. CYP1A2
D. CYP2C9
Correct Answer: B
Rationale: CYP3A4 metabolizes approximately 50% of
marketed drugs and is inhibited/induced by many agents
(e.g., grapefruit juice, rifampin, ketoconazole).
2
,4. A patient on digoxin starts clarithromycin. The digoxin
level rises to toxic levels. This is likely due to:
A. Inhibition of CYP3A4
B. Induction of P-glycoprotein
C. Inhibition of P-glycoprotein
D. Competition for albumin binding
Correct Answer: C
Rationale: Clarithromycin inhibits P-glycoprotein (P-gp) in
the gut and kidney, increasing digoxin absorption and
decreasing renal secretion. Digoxin is not significantly
metabolized by CYP450.
5. Which route of administration completely bypasses
first-pass metabolism?
A. Oral
B. Sublingual
3
, C. Rectal
D. Subcutaneous
Correct Answer: B
Rationale: Sublingual and IV routes avoid first-pass
metabolism entirely. Rectal bypasses ~50% but not
complete. Subcutaneous requires absorption but avoids
portal circulation; however, "completely bypasses" is best
answered by sublingual/IV.
6. A drug's half-life is 12 hours. Approximately how many
hours to reach steady state?
A. 24 hours
B. 36 hours
C. 48 hours
D. 60 hours
Correct Answer: D
Rationale: Steady state is reached in 4–5 half-lives. 5 ×
12 = 60 hours. 4 × 12 = 48 hours (93.75% steady state),
4
