CLAYTON’S BASIC PHARMACOLOGY FOR NURSES
STUDY GUIDE WITH QUESTIONS AND CORRECT
ANSWERS 2026
1. A nurse is reviewing the four phases of pharmacokinetics. Which phase involves
the movement of a drug from the site of administration into the bloodstream?
A. Distribution
B. Metabolism
C. Absorption
D. Excretion
Correct Answer: C
Explanation: Absorption is the movement of a drug from its site of administration
into the bloodstream. Distribution is transport to tissues; metabolism is
biotransformation; excretion is elimination from the body.
2. A patient receives a drug with a half-life of 8 hours. How many hours will it take
for the drug to reach steady state?
A. 16 hours
B. 24 hours
C. 40 hours
D. 80 hours
Correct Answer: C
*Explanation: Steady state is reached after approximately 5 half-lives. 5 × 8 hours
= 40 hours. Options A, B, and D do not reflect the 5 half-life rule.*
3. A nurse administers an enteric-coated oral tablet. Which statement best explains
the purpose of enteric coating?
A. To enhance absorption in the stomach
B. To allow the drug to dissolve in the small intestine and prevent gastric irritation
C. To increase the first-pass effect
, D. To prolong the duration of action in the mouth
Correct Answer: B
Explanation: Enteric coating prevents dissolution in the acidic stomach, protecting
the drug or the gastric mucosa, and allows dissolution in the alkaline small
intestine. Options A, C, and D are incorrect functions of enteric coating.
4. A patient is prescribed a highly protein-bound drug. Another highly protein-
bound drug is added. What is the most likely effect?
A. Decreased risk of toxicity
B. Increased free fraction of both drugs
C. Decreased pharmacological effect of both drugs
D. Increased drug excretion
Correct Answer: B
Explanation: Competition for protein binding sites increases the free (unbound)
fraction of each drug, potentially increasing effect and toxicity. Option A is
opposite; C and D are not direct results.
5. A nurse is teaching about the cytochrome P-450 system. Which statement by the
patient indicates correct understanding?
A. "This system always increases drug excretion."
B. "This system metabolizes many drugs, and some drugs can inhibit or induce
these enzymes."
C. "The cytochrome P-450 system only affects intravenous drugs."
D. "This system is located primarily in the kidneys."
Correct Answer: B
*Explanation: Cytochrome P-450 enzymes in the liver metabolize many drugs;
inhibition or induction alters drug levels. A, C, and D are false statements about
this system.*
6. Which patient would be at greatest risk for drug toxicity due to altered
pharmacokinetics?
, A. A 25-year-old with a urinary tract infection
B. A 45-year-old with hypertension
C. A 70-year-old with reduced renal function
D. A 30-year-old with a fractured tibia
Correct Answer: C
Explanation: Elderly patients with reduced renal function have decreased excretion,
increasing toxicity risk. Younger patients with normal organ function are at lower
risk.
7. A drug has a therapeutic index of 2. This indicates:
A. The drug is extremely safe
B. The drug has a narrow margin of safety
C. The drug has no toxic effects
D. The drug requires no monitoring
Correct Answer: B
Explanation: Low therapeutic index (close to 1) indicates narrow margin between
effective and toxic doses. An index of 2 is low, meaning narrow safety margin. A, C,
and D are incorrect.
8. A patient is taking warfarin and begins taking rifampin, a strong CYP450 inducer.
The nurse expects the INR to:
A. Increase, increasing bleeding risk
B. Decrease, reducing anticoagulant effect
C. Remain unchanged
D. Initially increase then normalize
Correct Answer: B
Explanation: Rifampin induces warfarin metabolism, decreasing INR and
anticoagulant effect. Option A would occur with CYP inhibition; C and D are
incorrect.
, 9. A nurse is reviewing a patient’s medication list and identifies a drug that
undergoes extensive first-pass effect. Which route would bypass this effect?
A. Oral
B. Sublingual
C. Rectal (lower portion)
D. Intravenous
Correct Answer: B
Explanation: Sublingual administration allows absorption directly into systemic
circulation, bypassing hepatic portal circulation and first-pass metabolism. Oral
does not bypass; rectal is partial; IV bypasses but not first-pass defined as
absorption route.
10. A patient receives an intravenous bolus of a drug. Which pharmacokinetic phase
begins immediately after administration?
A. Absorption
B. Distribution
C. Metabolism
D. Excretion
Correct Answer: B
Explanation: With IV administration, absorption is bypassed; distribution begins
immediately as drug enters systemic circulation. Metabolism and excretion follow
later.
11. A patient’s liver enzymes are elevated. The nurse anticipates that metabolism of
which type of drug may be most affected?
A. Water-soluble drugs
B. Lipid-soluble drugs
C. Highly ionized drugs
D. Large-molecule drugs
Correct Answer: B
Explanation: Lipid-soluble drugs require hepatic metabolism to become water
soluble for excretion. Water-soluble drugs are excreted more readily by kidneys
without metabolism. C and D are less directly affected.
STUDY GUIDE WITH QUESTIONS AND CORRECT
ANSWERS 2026
1. A nurse is reviewing the four phases of pharmacokinetics. Which phase involves
the movement of a drug from the site of administration into the bloodstream?
A. Distribution
B. Metabolism
C. Absorption
D. Excretion
Correct Answer: C
Explanation: Absorption is the movement of a drug from its site of administration
into the bloodstream. Distribution is transport to tissues; metabolism is
biotransformation; excretion is elimination from the body.
2. A patient receives a drug with a half-life of 8 hours. How many hours will it take
for the drug to reach steady state?
A. 16 hours
B. 24 hours
C. 40 hours
D. 80 hours
Correct Answer: C
*Explanation: Steady state is reached after approximately 5 half-lives. 5 × 8 hours
= 40 hours. Options A, B, and D do not reflect the 5 half-life rule.*
3. A nurse administers an enteric-coated oral tablet. Which statement best explains
the purpose of enteric coating?
A. To enhance absorption in the stomach
B. To allow the drug to dissolve in the small intestine and prevent gastric irritation
C. To increase the first-pass effect
, D. To prolong the duration of action in the mouth
Correct Answer: B
Explanation: Enteric coating prevents dissolution in the acidic stomach, protecting
the drug or the gastric mucosa, and allows dissolution in the alkaline small
intestine. Options A, C, and D are incorrect functions of enteric coating.
4. A patient is prescribed a highly protein-bound drug. Another highly protein-
bound drug is added. What is the most likely effect?
A. Decreased risk of toxicity
B. Increased free fraction of both drugs
C. Decreased pharmacological effect of both drugs
D. Increased drug excretion
Correct Answer: B
Explanation: Competition for protein binding sites increases the free (unbound)
fraction of each drug, potentially increasing effect and toxicity. Option A is
opposite; C and D are not direct results.
5. A nurse is teaching about the cytochrome P-450 system. Which statement by the
patient indicates correct understanding?
A. "This system always increases drug excretion."
B. "This system metabolizes many drugs, and some drugs can inhibit or induce
these enzymes."
C. "The cytochrome P-450 system only affects intravenous drugs."
D. "This system is located primarily in the kidneys."
Correct Answer: B
*Explanation: Cytochrome P-450 enzymes in the liver metabolize many drugs;
inhibition or induction alters drug levels. A, C, and D are false statements about
this system.*
6. Which patient would be at greatest risk for drug toxicity due to altered
pharmacokinetics?
, A. A 25-year-old with a urinary tract infection
B. A 45-year-old with hypertension
C. A 70-year-old with reduced renal function
D. A 30-year-old with a fractured tibia
Correct Answer: C
Explanation: Elderly patients with reduced renal function have decreased excretion,
increasing toxicity risk. Younger patients with normal organ function are at lower
risk.
7. A drug has a therapeutic index of 2. This indicates:
A. The drug is extremely safe
B. The drug has a narrow margin of safety
C. The drug has no toxic effects
D. The drug requires no monitoring
Correct Answer: B
Explanation: Low therapeutic index (close to 1) indicates narrow margin between
effective and toxic doses. An index of 2 is low, meaning narrow safety margin. A, C,
and D are incorrect.
8. A patient is taking warfarin and begins taking rifampin, a strong CYP450 inducer.
The nurse expects the INR to:
A. Increase, increasing bleeding risk
B. Decrease, reducing anticoagulant effect
C. Remain unchanged
D. Initially increase then normalize
Correct Answer: B
Explanation: Rifampin induces warfarin metabolism, decreasing INR and
anticoagulant effect. Option A would occur with CYP inhibition; C and D are
incorrect.
, 9. A nurse is reviewing a patient’s medication list and identifies a drug that
undergoes extensive first-pass effect. Which route would bypass this effect?
A. Oral
B. Sublingual
C. Rectal (lower portion)
D. Intravenous
Correct Answer: B
Explanation: Sublingual administration allows absorption directly into systemic
circulation, bypassing hepatic portal circulation and first-pass metabolism. Oral
does not bypass; rectal is partial; IV bypasses but not first-pass defined as
absorption route.
10. A patient receives an intravenous bolus of a drug. Which pharmacokinetic phase
begins immediately after administration?
A. Absorption
B. Distribution
C. Metabolism
D. Excretion
Correct Answer: B
Explanation: With IV administration, absorption is bypassed; distribution begins
immediately as drug enters systemic circulation. Metabolism and excretion follow
later.
11. A patient’s liver enzymes are elevated. The nurse anticipates that metabolism of
which type of drug may be most affected?
A. Water-soluble drugs
B. Lipid-soluble drugs
C. Highly ionized drugs
D. Large-molecule drugs
Correct Answer: B
Explanation: Lipid-soluble drugs require hepatic metabolism to become water
soluble for excretion. Water-soluble drugs are excreted more readily by kidneys
without metabolism. C and D are less directly affected.
