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Pharmacologic Principles – Test Bank Pharmacokinetics &
Pharmacodynamics Deep Dive
(Inspired by Pharmacology and the Nursing Process, 10th Ed. by Lilley)
, 2
1. A nurse is calculating a loading dose for a patient starting a drug with a
large volume of distribution (Vd). Which pharmacokinetic principle
supports the need for a higher loading dose?
A. The drug is protein-bound in plasma.
B. The drug is metabolized slowly by the liver.
C. The drug distributes extensively into tissues, requiring more drug to
reach therapeutic plasma levels.
D. The drug is excreted rapidly by the kidneys.
Rationale:
A drug with a large Vd distributes widely into body tissues, reducing the
amount remaining in the plasma. To quickly reach therapeutic levels in the
bloodstream, a higher loading dose is necessary. This ensures effective
concentration despite tissue uptake.
2. Which scenario best illustrates the concept of zero-order kinetics?
A. A constant percentage of the drug is eliminated per hour.
B. A fixed amount of drug is eliminated regardless of the concentration.
C. The drug elimination half-life remains constant.
D. Clearance increases as the dose increases.
Rationale:
Zero-order kinetics means a constant amount, not proportion, of drug is
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eliminated per unit time (e.g., 10 mg/hour). This can lead to unpredictable
accumulation when dosing increases, unlike first-order kinetics where a
constant fraction is cleared.
3. A patient’s creatinine clearance drops from 90 to 30 mL/min. What
effect is most likely for a drug eliminated primarily by the kidneys?
A. Increased receptor sensitivity
B. Improved drug bioavailability
C. Prolonged drug half-life and risk of accumulation
D. Faster hepatic metabolism
Rationale:
Reduced renal clearance prolongs half-life, raising plasma drug concentration
over time. This increases the risk of toxicity unless dosing adjustments (e.g.,
reduced dose or extended interval) are made to prevent accumulation.
4. When two medications are CYP3A4 substrates are taken together, what
pharmacokinetic interaction is most concerning?
A. Decreased absorption of one drug
B. Competition for metabolism leading to increased plasma levels
C. Enhanced excretion via renal pathways
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D. Inhibition of protein binding sites
Rationale:
Drugs that rely on the same CYP450 enzyme can compete, leading to slower
metabolism and higher plasma levels of one or both drugs. This increases the
risk of adverse effects or toxicity due to reduced clearance.
5. The nurse is teaching about prodrugs. Why is this concept clinically
important?
A. Prodrugs are never safe in hepatic impairment.
B. Prodrugs require metabolic activation, so liver function directly
impacts drug efficacy.
C. All prodrugs bypass first-pass metabolism.
D. Prodrugs eliminate the need for dose adjustments in renal disease.
Rationale:
Prodrugs are inactive until the liver converts them into active metabolites.
Impaired hepatic function can prevent activation, resulting in therapeutic
failure or inconsistent effects. Monitoring liver function helps ensure
effectiveness.
6. What statement indicates student misunderstanding of bioavailability?
Pharmacologic Principles – Test Bank Pharmacokinetics &
Pharmacodynamics Deep Dive
(Inspired by Pharmacology and the Nursing Process, 10th Ed. by Lilley)
, 2
1. A nurse is calculating a loading dose for a patient starting a drug with a
large volume of distribution (Vd). Which pharmacokinetic principle
supports the need for a higher loading dose?
A. The drug is protein-bound in plasma.
B. The drug is metabolized slowly by the liver.
C. The drug distributes extensively into tissues, requiring more drug to
reach therapeutic plasma levels.
D. The drug is excreted rapidly by the kidneys.
Rationale:
A drug with a large Vd distributes widely into body tissues, reducing the
amount remaining in the plasma. To quickly reach therapeutic levels in the
bloodstream, a higher loading dose is necessary. This ensures effective
concentration despite tissue uptake.
2. Which scenario best illustrates the concept of zero-order kinetics?
A. A constant percentage of the drug is eliminated per hour.
B. A fixed amount of drug is eliminated regardless of the concentration.
C. The drug elimination half-life remains constant.
D. Clearance increases as the dose increases.
Rationale:
Zero-order kinetics means a constant amount, not proportion, of drug is
, 3
eliminated per unit time (e.g., 10 mg/hour). This can lead to unpredictable
accumulation when dosing increases, unlike first-order kinetics where a
constant fraction is cleared.
3. A patient’s creatinine clearance drops from 90 to 30 mL/min. What
effect is most likely for a drug eliminated primarily by the kidneys?
A. Increased receptor sensitivity
B. Improved drug bioavailability
C. Prolonged drug half-life and risk of accumulation
D. Faster hepatic metabolism
Rationale:
Reduced renal clearance prolongs half-life, raising plasma drug concentration
over time. This increases the risk of toxicity unless dosing adjustments (e.g.,
reduced dose or extended interval) are made to prevent accumulation.
4. When two medications are CYP3A4 substrates are taken together, what
pharmacokinetic interaction is most concerning?
A. Decreased absorption of one drug
B. Competition for metabolism leading to increased plasma levels
C. Enhanced excretion via renal pathways
, 4
D. Inhibition of protein binding sites
Rationale:
Drugs that rely on the same CYP450 enzyme can compete, leading to slower
metabolism and higher plasma levels of one or both drugs. This increases the
risk of adverse effects or toxicity due to reduced clearance.
5. The nurse is teaching about prodrugs. Why is this concept clinically
important?
A. Prodrugs are never safe in hepatic impairment.
B. Prodrugs require metabolic activation, so liver function directly
impacts drug efficacy.
C. All prodrugs bypass first-pass metabolism.
D. Prodrugs eliminate the need for dose adjustments in renal disease.
Rationale:
Prodrugs are inactive until the liver converts them into active metabolites.
Impaired hepatic function can prevent activation, resulting in therapeutic
failure or inconsistent effects. Monitoring liver function helps ensure
effectiveness.
6. What statement indicates student misunderstanding of bioavailability?
