Complete Guide with Questions, Answers & Rationales | Summer
Semester 2025/2026 | Graded A+
Domain 1: Pharmacokinetics and Pharmacodynamics
Question 1
The study of how the body affects a drug (absorption, distribution, metabolism,
excretion) is called:
A. Pharmacodynamics
B. Pharmacokinetics
C. Pharmacotherapeutics
D. Pharmacogenomics
Correct Answer: B
Rationale: Pharmacokinetics describes what the body does to the drug: absorption,
distribution, metabolism, and excretion (ADME). Pharmacodynamics describes what
the drug does to the body .
Question 2
The study of what the drug does to the body (mechanism of action, receptor binding,
dose-response) is called:
A. Pharmacokinetics
B. Pharmacodynamics
C. Pharmacogenetics
D. Pharmacoepidemiology
Correct Answer: B
Rationale: Pharmacodynamics involves the drug's effects on the body, including
receptor interactions, signal transduction, and physiological responses .
Question 3
The fraction of an administered dose of drug that reaches systemic circulation
unchanged is called:
A. Volume of distribution
B. Half-life
C. Bioavailability
D. Clearance
pg. 1
,Correct Answer: C
Rationale: Bioavailability (F) is the fraction of the administered dose that reaches
systemic circulation. IV drugs have 100% bioavailability; oral drugs have lower
bioavailability due to first-pass metabolism .
Question 4
A patient with severe heart failure (reduced cardiac output and hepatic congestion) is
prescribed a medication with high first-pass metabolism and high hepatic extraction
ratio. The NP expects which change in oral bioavailability?
A. Increased bioavailability due to reduced hepatic clearance
B. Decreased bioavailability due to reduced liver blood flow
C. No change
D. Decreased absorption due to gut edema
Correct Answer: A
Rationale: High extraction ratio drugs are flow-limited. Reduced cardiac output leads
to reduced hepatic blood flow, which decreases first-pass metabolism and increases oral
bioavailability. Dose reduction may be needed .
Question 5
The NP prescribes a drug that is a weak base (pKa 8.4). In the small intestine (pH 7.4),
the drug will be predominantly:
A. Non-ionized and well absorbed
B. Ionized and poorly absorbed
C. Trapped in the gut lumen
D. Completely degraded
Correct Answer: B
Rationale: Using the Henderson-Hasselbalch equation: pH = pKa + log (base/acid). At
pH 7.4 and pKa 8.4, the ratio is 7.4 - 8.4 = -1 = log(0.1) → base:acid = 0.1 → 10% non-
ionized base. The drug is predominantly ionized (90%) and poorly absorbed .
Question 6
A drug with a very large volume of distribution (Vd) is likely to:
A. Be highly bound to plasma proteins and remain in the vascular space
B. Be extensively distributed into tissues (e.g., lipophilic drugs)
C. Have a short half-life
D. Be excreted unchanged in urine
pg. 2
, Correct Answer: B
Rationale: A large Vd indicates that the drug is extensively distributed into tissues.
Lipophilic drugs (e.g., digoxin, amiodarone) have large Vd values. Digoxin has a Vd of
approximately 7 L/kg due to extensive tissue distribution .
Question 7
Warfarin has a small volume of distribution (approximately 0.1 L/kg) because it is:
A. Highly protein-bound (99% bound to albumin)
B. Lipophilic
C. Extensively distributed into fat tissue
D. Renally excreted
Correct Answer: A
Rationale: Warfarin is highly bound to plasma albumin (99%), limiting its distribution
to the vascular space and resulting in a small Vd .
Question 8
The half-life (t½) of a drug is defined as:
A. The time required for the plasma concentration to decrease by 50%
B. The time required for the drug to be completely eliminated
C. The time required for the drug to reach peak concentration
D. The time required for the drug to be absorbed
Correct Answer: A
Rationale: Half-life is the time it takes for the plasma concentration of a drug to
decrease by 50% during elimination. It takes approximately 4-5 half-lives to reach
steady state .
Question 9
Steady state is achieved after approximately:
A. 1 half-life
B. 2-3 half-lives
C. 4-5 half-lives
D. 10 half-lives
Correct Answer: C
Rationale: Steady state (the point at which drug intake equals drug elimination) is
achieved after approximately 4-5 half-lives of continuous dosing .
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