RN PHARMACOLOGY A RELIAS EXAM QUESTIONS |
WITH DETAILED RATIONALES (2026) ACTUAL REAL
EXAM ACCURATE QUESTIONS AND ANSWERS WITH
RATIONALES | VERIFIED AND LATEST UPDATED |
GUARANTEED PASS
Question 1:
A patient is prescribed a medication that is highly protein-bound (95% bound).
Another medication that is also highly protein-bound is added to the regimen. The
nurse should monitor for which potential effect?
A. Decreased therapeutic effect of the first medication
B. Increased risk of toxicity due to displacement
C. No change in drug levels
D. Decreased renal excretion
Correct Answer: B. Increased risk of toxicity due to displacement
Rationale: When two highly protein-bound medications are administered together,
they compete for binding sites on plasma proteins (primarily albumin).
Displacement increases the free (unbound) concentration of the displaced drug,
leading to enhanced pharmacologic effect and potential toxicity. This is
particularly dangerous with drugs that have a narrow therapeutic index, such as
warfarin and phenytoin.
Question 2:
A patient is prescribed a medication that is metabolized by the CYP3A4 enzyme
system. The patient starts taking grapefruit juice daily. The nurse should anticipate
which effect?
A. Decreased drug levels
B. Increased drug levels and risk of toxicity
C. No change in drug levels
D. Increased drug excretion
Correct Answer: B. Increased drug levels and risk of toxicity
,Rationale: Grapefruit juice inhibits CYP3A4 enzymes in the intestinal wall and
liver, reducing the metabolism of drugs that are substrates of this enzyme. This
leads to increased serum drug levels and increased risk of toxicity. This interaction
is significant for drugs like statins, calcium channel blockers, cyclosporine, and
certain benzodiazepines. Patients should be advised to avoid grapefruit juice while
taking these medications.
Question 3:
A drug with zero-order kinetics is prescribed. Which statement is true regarding
this medication?
A. A constant fraction of drug is eliminated per hour
B. A constant amount of drug is eliminated per hour
C. Half-life remains constant regardless of dose
D. Doubling the dose doubles the elimination rate
Correct Answer: B. A constant amount of drug is eliminated per hour
Rationale: Zero-order kinetics means a constant amount of drug is eliminated per
unit of time, regardless of concentration. This results in a non-linear elimination
pattern where half-life increases with dose. Examples include phenytoin, aspirin (at
high doses), and alcohol. This differs from first-order kinetics, where a constant
fraction is eliminated per unit of time.
Question 4:
A patient has a serum creatinine level of 2.5 mg/dL. The nurse should anticipate
which adjustment for a renally excreted medication?
A. Increase the dose
B. Decrease the dose
C. Administer the dose more frequently
D. No adjustment needed
Correct Answer: B. Decrease the dose
Rationale: Elevated serum creatinine (> 1.2-1.5 mg/dL) indicates decreased renal
function. For medications that are primarily renally excreted, the dose should be
decreased to prevent accumulation and toxicity. Creatinine clearance is a more
,accurate measure of renal function and should be used to guide dosing. Drugs
requiring renal dose adjustment include aminoglycosides, vancomycin, digoxin,
and many ACE inhibitors.
Question 5:
What is the therapeutic index of a medication?
A. The time required for the drug to reach steady state
B. The ratio between the toxic dose and the therapeutic dose
C. The amount of drug that binds to plasma proteins
D. The rate at which the drug is eliminated from the body
Correct Answer: B. The ratio between the toxic dose and the therapeutic dose
Rationale: The therapeutic index (TI) is the ratio of the median toxic dose (TD50)
to the median effective dose (ED50). A narrow therapeutic index indicates a small
margin of safety, requiring careful dosing and monitoring (e.g., digoxin, lithium,
warfarin). A wide therapeutic index indicates a large safety margin (e.g., most
penicillins).
Question 6:
A patient is receiving an IV infusion of a medication. The nurse understands that
the bioavailability of an IV medication is:
A. 50-75%
B. 75-90%
C. 100%
D. Variable depending on the drug
Correct Answer: C. 100%
Rationale: Intravenous (IV) administration provides 100% bioavailability because
the medication enters the systemic circulation directly, bypassing absorption
barriers and first-pass metabolism. Bioavailability is the fraction of administered
drug that reaches systemic circulation. Other routes (oral, IM, subcutaneous) have
less than 100% bioavailability due to incomplete absorption and/or first-pass
metabolism.
, Question 7:
A patient is prescribed a medication that has a half-life of 4 hours. Approximately
how long will it take for the drug to reach steady state?
A. 4-8 hours
B. 8-12 hours
C. 16-20 hours
D. 24-48 hours
Correct Answer: C. 16-20 hours
Rationale: Steady state is achieved after approximately 4-5 half-lives of the drug.
With a half-life of 4 hours, steady state would be reached in 16-20 hours (4-5 × 4
hours = 16-20 hours). Steady state is the point at which the rate of drug
administration equals the rate of drug elimination, resulting in relatively constant
plasma concentrations.
Question 8:
Which laboratory value is most important to monitor when administering an
aminoglycoside antibiotic?
A. Liver function tests
B. Complete blood count
C. Peak and trough serum levels
D. Serum electrolytes
Correct Answer: C. Peak and trough serum levels
Rationale: Aminoglycosides (gentamicin, tobramycin, amikacin) have a narrow
therapeutic index and require monitoring of peak (to ensure therapeutic efficacy)
and trough (to prevent toxicity) serum levels. Trough levels are used to monitor for
nephrotoxicity and ototoxicity. Peak levels monitor efficacy against the infection.
Dosing should be based on renal function and serum levels.
Question 9:
A patient is taking a medication that undergoes significant first-pass metabolism.
Which route of administration would bypass this effect?
WITH DETAILED RATIONALES (2026) ACTUAL REAL
EXAM ACCURATE QUESTIONS AND ANSWERS WITH
RATIONALES | VERIFIED AND LATEST UPDATED |
GUARANTEED PASS
Question 1:
A patient is prescribed a medication that is highly protein-bound (95% bound).
Another medication that is also highly protein-bound is added to the regimen. The
nurse should monitor for which potential effect?
A. Decreased therapeutic effect of the first medication
B. Increased risk of toxicity due to displacement
C. No change in drug levels
D. Decreased renal excretion
Correct Answer: B. Increased risk of toxicity due to displacement
Rationale: When two highly protein-bound medications are administered together,
they compete for binding sites on plasma proteins (primarily albumin).
Displacement increases the free (unbound) concentration of the displaced drug,
leading to enhanced pharmacologic effect and potential toxicity. This is
particularly dangerous with drugs that have a narrow therapeutic index, such as
warfarin and phenytoin.
Question 2:
A patient is prescribed a medication that is metabolized by the CYP3A4 enzyme
system. The patient starts taking grapefruit juice daily. The nurse should anticipate
which effect?
A. Decreased drug levels
B. Increased drug levels and risk of toxicity
C. No change in drug levels
D. Increased drug excretion
Correct Answer: B. Increased drug levels and risk of toxicity
,Rationale: Grapefruit juice inhibits CYP3A4 enzymes in the intestinal wall and
liver, reducing the metabolism of drugs that are substrates of this enzyme. This
leads to increased serum drug levels and increased risk of toxicity. This interaction
is significant for drugs like statins, calcium channel blockers, cyclosporine, and
certain benzodiazepines. Patients should be advised to avoid grapefruit juice while
taking these medications.
Question 3:
A drug with zero-order kinetics is prescribed. Which statement is true regarding
this medication?
A. A constant fraction of drug is eliminated per hour
B. A constant amount of drug is eliminated per hour
C. Half-life remains constant regardless of dose
D. Doubling the dose doubles the elimination rate
Correct Answer: B. A constant amount of drug is eliminated per hour
Rationale: Zero-order kinetics means a constant amount of drug is eliminated per
unit of time, regardless of concentration. This results in a non-linear elimination
pattern where half-life increases with dose. Examples include phenytoin, aspirin (at
high doses), and alcohol. This differs from first-order kinetics, where a constant
fraction is eliminated per unit of time.
Question 4:
A patient has a serum creatinine level of 2.5 mg/dL. The nurse should anticipate
which adjustment for a renally excreted medication?
A. Increase the dose
B. Decrease the dose
C. Administer the dose more frequently
D. No adjustment needed
Correct Answer: B. Decrease the dose
Rationale: Elevated serum creatinine (> 1.2-1.5 mg/dL) indicates decreased renal
function. For medications that are primarily renally excreted, the dose should be
decreased to prevent accumulation and toxicity. Creatinine clearance is a more
,accurate measure of renal function and should be used to guide dosing. Drugs
requiring renal dose adjustment include aminoglycosides, vancomycin, digoxin,
and many ACE inhibitors.
Question 5:
What is the therapeutic index of a medication?
A. The time required for the drug to reach steady state
B. The ratio between the toxic dose and the therapeutic dose
C. The amount of drug that binds to plasma proteins
D. The rate at which the drug is eliminated from the body
Correct Answer: B. The ratio between the toxic dose and the therapeutic dose
Rationale: The therapeutic index (TI) is the ratio of the median toxic dose (TD50)
to the median effective dose (ED50). A narrow therapeutic index indicates a small
margin of safety, requiring careful dosing and monitoring (e.g., digoxin, lithium,
warfarin). A wide therapeutic index indicates a large safety margin (e.g., most
penicillins).
Question 6:
A patient is receiving an IV infusion of a medication. The nurse understands that
the bioavailability of an IV medication is:
A. 50-75%
B. 75-90%
C. 100%
D. Variable depending on the drug
Correct Answer: C. 100%
Rationale: Intravenous (IV) administration provides 100% bioavailability because
the medication enters the systemic circulation directly, bypassing absorption
barriers and first-pass metabolism. Bioavailability is the fraction of administered
drug that reaches systemic circulation. Other routes (oral, IM, subcutaneous) have
less than 100% bioavailability due to incomplete absorption and/or first-pass
metabolism.
, Question 7:
A patient is prescribed a medication that has a half-life of 4 hours. Approximately
how long will it take for the drug to reach steady state?
A. 4-8 hours
B. 8-12 hours
C. 16-20 hours
D. 24-48 hours
Correct Answer: C. 16-20 hours
Rationale: Steady state is achieved after approximately 4-5 half-lives of the drug.
With a half-life of 4 hours, steady state would be reached in 16-20 hours (4-5 × 4
hours = 16-20 hours). Steady state is the point at which the rate of drug
administration equals the rate of drug elimination, resulting in relatively constant
plasma concentrations.
Question 8:
Which laboratory value is most important to monitor when administering an
aminoglycoside antibiotic?
A. Liver function tests
B. Complete blood count
C. Peak and trough serum levels
D. Serum electrolytes
Correct Answer: C. Peak and trough serum levels
Rationale: Aminoglycosides (gentamicin, tobramycin, amikacin) have a narrow
therapeutic index and require monitoring of peak (to ensure therapeutic efficacy)
and trough (to prevent toxicity) serum levels. Trough levels are used to monitor for
nephrotoxicity and ototoxicity. Peak levels monitor efficacy against the infection.
Dosing should be based on renal function and serum levels.
Question 9:
A patient is taking a medication that undergoes significant first-pass metabolism.
Which route of administration would bypass this effect?
