Answers 100% Correct Answers With Explained Rationale |
2026/2027 Updates
Question 1.
A nurse is reviewing pharmacokinetics with a student nurse. The nurse correctly
explains that the process by which a drug moves from the site of administration into
the bloodstream is called:
A. Distribution.
B. Metabolism.
C. Absorption.
D. Excretion.
Correct Answer: C
Rationale: Absorption is the process by which a drug moves from its site of administration
into the bloodstream. Distribution is the transport of the drug throughout the body to
tissues and organs. Metabolism (biotransformation) is the chemical alteration of the drug,
primarily in the liver. Excretion (elimination) is the removal of the drug and its metabolites
from the body, primarily by the kidneys. The rate and extent of absorption depend on the
route of administration, blood flow, solubility, and presence of food.
Question 2.
A patient is prescribed propranolol orally. The nurse knows that because
propranolol undergoes extensive first-pass metabolism in the liver, the oral dose
must be higher than the intravenous dose to achieve the same therapeutic effect.
First-pass metabolism refers to the:
A. Rapid excretion of the drug by the kidneys before it reaches systemic circulation.
B. Metabolism of a drug by the liver after absorption from the GI tract but before it reaches
systemic circulation.
C. Initial binding of the drug to plasma proteins, making it temporarily inactive.
D. Rapid distribution of the drug to adipose tissue after IV administration.
Correct Answer: B
,Rationale: First-pass (first-pass hepatic) metabolism is the phenomenon in which a drug is
extensively metabolized by the liver after oral absorption from the gastrointestinal tract but
before reaching the systemic circulation. Drugs with high first-pass metabolism (e.g.,
propranolol, nitroglycerin, morphine, lidocaine) have significantly reduced bioavailability
when given orally, requiring higher oral doses or alternative routes (sublingual,
transdermal, IV) to achieve therapeutic levels. IV administration bypasses the first-pass
effect entirely.
Question 3.
A patient with liver cirrhosis is prescribed a medication that is primarily metabolized
by the hepatic cytochrome P450 enzyme system. The nurse knows that this patient is
at increased risk for:
A. Drug toxicity due to decreased metabolism and accumulation of the drug.
B. Therapeutic failure due to excessively rapid drug metabolism.
C. Enhanced drug excretion through the kidneys.
D. Increased protein binding, reducing free drug levels.
Correct Answer: A
Rationale: The liver is the primary site of drug metabolism via the cytochrome P450
(CYP450) enzyme system. In patients with liver cirrhosis or hepatic impairment, drug
metabolism is significantly reduced, leading to decreased clearance, prolonged half-life, and
accumulation of the drug and/or its active metabolites. This increases the risk of drug
toxicity. The nurse should monitor for signs of toxicity, expect lower doses or longer dosing
intervals, and avoid hepatotoxic drugs when possible.
Question 4.
A patient with chronic kidney disease (CKD) stage 4 is prescribed a medication that is
90% excreted unchanged by the kidneys. The nurse knows that the prescriber will
most likely:
A. Increase the dose to compensate for reduced renal function.
B. Reduce the dose or extend the dosing interval to prevent drug accumulation and toxicity.
C. Switch to the intravenous route to enhance absorption.
D. Add a hepatic enzyme inducer to increase metabolism.
, Correct Answer: B
Rationale: When a drug is primarily excreted unchanged by the kidneys, impaired renal
function (decreased GFR) leads to reduced clearance and accumulation of the drug in the
body. To prevent toxicity, the dose should be reduced or the dosing interval extended based
on the patient's creatinine clearance or eGFR. This is especially important for drugs with a
narrow therapeutic index (e.g., aminoglycosides, digoxin, lithium, vancomycin). The nurse
should monitor renal function, therapeutic drug levels, and signs of toxicity.
Question 5.
A patient asks why some medications are taken once daily while others are taken
multiple times per day. The nurse correctly explains that dosing frequency is
primarily determined by the drug's:
A. Bioavailability.
B. Half-life.
C. Protein binding.
D. First-pass effect.
Correct Answer: B
Rationale: Half-life (t½) is the time required for the plasma drug concentration to decrease
by 50%. It determines how frequently a drug must be administered to maintain therapeutic
plasma levels. Drugs with short half-lives require more frequent dosing (e.g., penicillin G
every 4–6 hours). Drugs with long half-lives can be dosed less frequently (e.g., amlodipine
once daily, digoxin once daily). Steady state (where drug elimination equals drug
administration) is reached after approximately 4–5 half-lives.
Question 6.
A patient is receiving a drug with a half-life of 6 hours. The nurse knows that steady-
state plasma concentration (where the amount of drug administered equals the
amount eliminated) will be reached after approximately:
A. 6 hours.
B. 12 hours.
C. 24–30 hours.
D. 48 hours.