Exam 2: NU150 Pharmacology Review | Questions & Answers | Grade A | 100% Correct
(Verified Solutions) - Galen
SECTION 1: PHARMACOKINETICS AND PHARMACODYNAMICS
(Questions 1-10)
Q1: A nurse is preparing to administer a medication that undergoes significant first-pass
metabolism in the liver. Which route of administration would be MOST appropriate to
maximize bioavailability of this drug?
A. Oral administration with a full glass of water
B. Sublingual administration
C. Intramuscular injection
D. Rectal suppository administration
Correct Answer: C
Rationale: Correct because intramuscular injection bypasses the hepatic portal
circulation, avoiding first-pass metabolism entirely. Oral and rectal routes deliver drug to
the liver via portal circulation, while sublingual absorption partially bypasses first-pass
but is less reliable than parenteral routes for high-extraction drugs.
Q2: A patient receiving warfarin is started on phenytoin for seizure prophylaxis. The
nurse should monitor for which potential interaction based on CYP450 enzyme activity?
A. Decreased warfarin metabolism requiring dose reduction
,B. Increased warfarin metabolism requiring dose increase
C. No interaction since both drugs use different CYP450 isoenzymes
D. Increased phenytoin toxicity due to warfarin inhibition
Correct Answer: B
Rationale: Correct because phenytoin is a potent CYP450 enzyme inducer, specifically
inducing CYP2C9 and CYP2C19, which metabolize warfarin. This increases warfarin
metabolism, decreasing its anticoagulant effect and requiring dose adjustment to
maintain therapeutic INR levels.
Q3: A drug has a volume of distribution (Vd) of 40 liters and a clearance rate of 4 L/hour.
What is the approximate elimination half-life of this drug?
A. 2 hours
B. 4 hours
C. 7 hours
D. 10 hours
Correct Answer: C
Rationale: Correct because half-life (t½) = (0.693 × Vd) / Clearance. Calculation: (0.693 ×
40 L) / 4 L/hr = 27. = 6.93 hours, which rounds to approximately 7 hours. This
formula demonstrates the relationship between drug distribution and elimination
kinetics.
,Q4: A patient with renal impairment is prescribed a drug that is primarily eliminated
unchanged by the kidneys. The nurse should anticipate which adjustment to prevent
drug accumulation?
A. Decreased loading dose and increased maintenance dose
B. Increased loading dose and decreased maintenance dose
C. Decreased loading dose and decreased maintenance dose
D. No dose adjustment needed if the drug is water-soluble
Correct Answer: B
Rationale: Correct because renal impairment slows elimination of renally cleared drugs.
The loading dose should remain unchanged (or slightly increased) to achieve
therapeutic concentration quickly, while the maintenance dose must be decreased to
prevent accumulation and toxicity due to prolonged half-life.
Q5: A nurse is teaching a patient about a new medication that is highly protein-bound
(95%). The patient asks why this matters. The nurse's best response is based on which
pharmacokinetic principle?
A. Highly protein-bound drugs have increased free drug available for therapeutic effect
B. Only the free, unbound fraction of drug is pharmacologically active and available for
metabolism
C. Protein binding increases the volume of distribution, requiring higher doses
D. Protein-bound drugs are rapidly eliminated by the kidneys
Correct Answer: B
, Rationale: Correct because drug molecules bound to plasma proteins (primarily
albumin) are too large to cross biological membranes or interact with receptors. Only
the free, unbound fraction (5% in this case) is pharmacologically active, available for
distribution, metabolism, and elimination.
Q6: A drug reaches steady-state concentration after approximately 5 half-lives. If a drug
has a half-life of 8 hours, how long will it take to reach steady state with continuous
administration?
A. 8 hours
B. 16 hours
C. 32 hours
D. 40 hours
Correct Answer: D
Rationale: Correct because steady state is achieved after approximately 5 half-lives of
continuous administration. Calculation: 5 × 8 hours = 40 hours. At steady state, the rate
of drug administration equals the rate of elimination, resulting in stable plasma
concentrations.
Q7: A nurse is caring for a patient who received a loading dose of digoxin followed by
maintenance doses. The purpose of the loading dose is to:
A. Prevent first-pass metabolism
B. Achieve therapeutic plasma concentration rapidly
C. Increase the drug's half-life
(Verified Solutions) - Galen
SECTION 1: PHARMACOKINETICS AND PHARMACODYNAMICS
(Questions 1-10)
Q1: A nurse is preparing to administer a medication that undergoes significant first-pass
metabolism in the liver. Which route of administration would be MOST appropriate to
maximize bioavailability of this drug?
A. Oral administration with a full glass of water
B. Sublingual administration
C. Intramuscular injection
D. Rectal suppository administration
Correct Answer: C
Rationale: Correct because intramuscular injection bypasses the hepatic portal
circulation, avoiding first-pass metabolism entirely. Oral and rectal routes deliver drug to
the liver via portal circulation, while sublingual absorption partially bypasses first-pass
but is less reliable than parenteral routes for high-extraction drugs.
Q2: A patient receiving warfarin is started on phenytoin for seizure prophylaxis. The
nurse should monitor for which potential interaction based on CYP450 enzyme activity?
A. Decreased warfarin metabolism requiring dose reduction
,B. Increased warfarin metabolism requiring dose increase
C. No interaction since both drugs use different CYP450 isoenzymes
D. Increased phenytoin toxicity due to warfarin inhibition
Correct Answer: B
Rationale: Correct because phenytoin is a potent CYP450 enzyme inducer, specifically
inducing CYP2C9 and CYP2C19, which metabolize warfarin. This increases warfarin
metabolism, decreasing its anticoagulant effect and requiring dose adjustment to
maintain therapeutic INR levels.
Q3: A drug has a volume of distribution (Vd) of 40 liters and a clearance rate of 4 L/hour.
What is the approximate elimination half-life of this drug?
A. 2 hours
B. 4 hours
C. 7 hours
D. 10 hours
Correct Answer: C
Rationale: Correct because half-life (t½) = (0.693 × Vd) / Clearance. Calculation: (0.693 ×
40 L) / 4 L/hr = 27. = 6.93 hours, which rounds to approximately 7 hours. This
formula demonstrates the relationship between drug distribution and elimination
kinetics.
,Q4: A patient with renal impairment is prescribed a drug that is primarily eliminated
unchanged by the kidneys. The nurse should anticipate which adjustment to prevent
drug accumulation?
A. Decreased loading dose and increased maintenance dose
B. Increased loading dose and decreased maintenance dose
C. Decreased loading dose and decreased maintenance dose
D. No dose adjustment needed if the drug is water-soluble
Correct Answer: B
Rationale: Correct because renal impairment slows elimination of renally cleared drugs.
The loading dose should remain unchanged (or slightly increased) to achieve
therapeutic concentration quickly, while the maintenance dose must be decreased to
prevent accumulation and toxicity due to prolonged half-life.
Q5: A nurse is teaching a patient about a new medication that is highly protein-bound
(95%). The patient asks why this matters. The nurse's best response is based on which
pharmacokinetic principle?
A. Highly protein-bound drugs have increased free drug available for therapeutic effect
B. Only the free, unbound fraction of drug is pharmacologically active and available for
metabolism
C. Protein binding increases the volume of distribution, requiring higher doses
D. Protein-bound drugs are rapidly eliminated by the kidneys
Correct Answer: B
, Rationale: Correct because drug molecules bound to plasma proteins (primarily
albumin) are too large to cross biological membranes or interact with receptors. Only
the free, unbound fraction (5% in this case) is pharmacologically active, available for
distribution, metabolism, and elimination.
Q6: A drug reaches steady-state concentration after approximately 5 half-lives. If a drug
has a half-life of 8 hours, how long will it take to reach steady state with continuous
administration?
A. 8 hours
B. 16 hours
C. 32 hours
D. 40 hours
Correct Answer: D
Rationale: Correct because steady state is achieved after approximately 5 half-lives of
continuous administration. Calculation: 5 × 8 hours = 40 hours. At steady state, the rate
of drug administration equals the rate of elimination, resulting in stable plasma
concentrations.
Q7: A nurse is caring for a patient who received a loading dose of digoxin followed by
maintenance doses. The purpose of the loading dose is to:
A. Prevent first-pass metabolism
B. Achieve therapeutic plasma concentration rapidly
C. Increase the drug's half-life
