NAPLEX EXAM 2025|REAL EXAM QUESTIONS WITH
COMPREHENSIVE ANSWERS AND DETAILED
RATIONALE|EXPERT VERIFIED FOR GUARANTEED
PASS|LATEST VERSION
1. Which of the following drugs is a prodrug that is metabolized to its active form via CYP2D6?
A) Codeine
B) Ibuprofen
C) Warfarin
D) Acetaminophen
Answer: A) Codeine
Rationale: Codeine requires CYP2D6-mediated conversion to morphine to exert its analgesic
effect.
2. A 65-year-old patient with renal impairment is prescribed gentamicin. Which dosing
adjustment is most appropriate?
A) Increase the dosing interval
B) Increase the dose
C) Use a loading dose without adjustment
D) No adjustment is needed
Answer: A) Increase the dosing interval
Rationale: Gentamicin is cleared renally, so prolonging the dosing interval helps reduce the risk
of toxicity.
3. A patient is taking warfarin. Which vitamin can antagonize its effect if taken in excess?
A) Vitamin A
B) Vitamin K
C) Vitamin C
D) Vitamin D
Answer: B) Vitamin K
Rationale: Vitamin K is necessary for clotting factor synthesis and high intakes can counteract
warfarin’s anticoagulant effect.
4. Which of the following medications is a beta‐blocker commonly used in hypertension
management?
,A) Lisinopril
B) Atenolol
C) Amlodipine
D) Losartan
Answer: B) Atenolol
Rationale: Atenolol is a selective beta-1 blocker, whereas the others are from different drug
classes.
5. What is the mechanism of action of ACE inhibitors?
A) Block angiotensin II receptors
B) Inhibit renin release
C) Prevent conversion of angiotensin I to angiotensin II
D) Stimulate aldosterone secretion
Answer: C) Prevent conversion of angiotensin I to angiotensin II
Rationale: ACE inhibitors block the enzyme responsible for converting angiotensin I into
angiotensin II, a potent vasoconstrictor.
6. Which of the following drugs is contraindicated in pregnancy due to its teratogenic potential?
A) Labetalol
B) ACE inhibitors
C) Metformin
D) Heparin
Answer: B) ACE inhibitors
Rationale: ACE inhibitors are associated with fetal renal damage and are contraindicated during
pregnancy.
7. In a pharmacy calculation, if 250 mg of a drug is to be administered and the available
concentration is 50 mg/mL, what is the volume to administer?
A) 2 mL
B) 3 mL
C) 5 mL
D) 7 mL
Answer: C) 5 mL
Rationale: Volume = 250 mg ÷ 50 mg/mL = 5 mL.
,8. Which antibiotic is known for its potential to cause tendon rupture, especially in older adults?
A) Ciprofloxacin
B) Amoxicillin
C) Azithromycin
D) Doxycycline
Answer: A) Ciprofloxacin
Rationale: Fluoroquinolones like ciprofloxacin can damage tendons, increasing rupture risk in
the elderly.
9. Which of the following is the antidote for acetaminophen overdose?
A) Naloxone
B) N-acetylcysteine
C) Flumazenil
D) Vitamin K
Answer: B) N-acetylcysteine
Rationale: N-acetylcysteine replenishes glutathione, helping to detoxify the harmful metabolite
of acetaminophen.
10. A patient experiences bradycardia and hypotension after administration of a beta-blocker.
Which of the following is most likely the cause?
A) Excessive beta-1 blockade
B) Excessive beta-2 blockade
C) ACE inhibition
D) Calcium channel blockade
Answer: A) Excessive beta-1 blockade
Rationale: Beta-blockers decrease heart rate and contractility by blocking beta-1 receptors in the
heart.
11. A patient taking digoxin is prescribed verapamil for hypertension. What is the most likely
interaction?
A) Increased digoxin clearance
B) Decreased digoxin clearance
C) No interaction
D) Increased digoxin excretion
Answer: B) Decreased digoxin clearance
Rationale: Verapamil decreases digoxin clearance, raising the risk for digoxin toxicity.
, 12. Which of the following conditions is a contraindication for the use of thiazide diuretics?
A) Hyperkalemia
B) Hypokalemia
C) Gout
D) Hyponatremia
Answer: C) Gout
Rationale: Thiazides can elevate uric acid levels, potentially precipitating gout attacks.
13. Which of the following is the mechanism of action of statins?
A) Inhibit cholesterol absorption in the gut
B) Inhibit HMG-CoA reductase
C) Increase LDL receptor expression
D) Inhibit bile acid reabsorption
Answer: B) Inhibit HMG-CoA reductase
Rationale: Statins reduce cholesterol synthesis by blocking HMG-CoA reductase.
14. Which anticoagulant requires monitoring of the INR for dose adjustments?
A) Heparin
B) Enoxaparin
C) Warfarin
D) Dabigatran
Answer: C) Warfarin
Rationale: Warfarin’s narrow therapeutic index necessitates regular INR monitoring.
15. Which drug is commonly used as a first-line treatment for type 2 diabetes mellitus?
A) Insulin
B) Metformin
C) Sulfonylureas
D) Thiazolidinediones
Answer: B) Metformin
Rationale: Metformin is the preferred initial therapy for type 2 diabetes because of its
effectiveness and favorable safety profile.
16. In a calculation, if a patient requires 0.8 mg/kg of a medication and weighs 75 kg, what is the
total dose?
A) 50 mg
COMPREHENSIVE ANSWERS AND DETAILED
RATIONALE|EXPERT VERIFIED FOR GUARANTEED
PASS|LATEST VERSION
1. Which of the following drugs is a prodrug that is metabolized to its active form via CYP2D6?
A) Codeine
B) Ibuprofen
C) Warfarin
D) Acetaminophen
Answer: A) Codeine
Rationale: Codeine requires CYP2D6-mediated conversion to morphine to exert its analgesic
effect.
2. A 65-year-old patient with renal impairment is prescribed gentamicin. Which dosing
adjustment is most appropriate?
A) Increase the dosing interval
B) Increase the dose
C) Use a loading dose without adjustment
D) No adjustment is needed
Answer: A) Increase the dosing interval
Rationale: Gentamicin is cleared renally, so prolonging the dosing interval helps reduce the risk
of toxicity.
3. A patient is taking warfarin. Which vitamin can antagonize its effect if taken in excess?
A) Vitamin A
B) Vitamin K
C) Vitamin C
D) Vitamin D
Answer: B) Vitamin K
Rationale: Vitamin K is necessary for clotting factor synthesis and high intakes can counteract
warfarin’s anticoagulant effect.
4. Which of the following medications is a beta‐blocker commonly used in hypertension
management?
,A) Lisinopril
B) Atenolol
C) Amlodipine
D) Losartan
Answer: B) Atenolol
Rationale: Atenolol is a selective beta-1 blocker, whereas the others are from different drug
classes.
5. What is the mechanism of action of ACE inhibitors?
A) Block angiotensin II receptors
B) Inhibit renin release
C) Prevent conversion of angiotensin I to angiotensin II
D) Stimulate aldosterone secretion
Answer: C) Prevent conversion of angiotensin I to angiotensin II
Rationale: ACE inhibitors block the enzyme responsible for converting angiotensin I into
angiotensin II, a potent vasoconstrictor.
6. Which of the following drugs is contraindicated in pregnancy due to its teratogenic potential?
A) Labetalol
B) ACE inhibitors
C) Metformin
D) Heparin
Answer: B) ACE inhibitors
Rationale: ACE inhibitors are associated with fetal renal damage and are contraindicated during
pregnancy.
7. In a pharmacy calculation, if 250 mg of a drug is to be administered and the available
concentration is 50 mg/mL, what is the volume to administer?
A) 2 mL
B) 3 mL
C) 5 mL
D) 7 mL
Answer: C) 5 mL
Rationale: Volume = 250 mg ÷ 50 mg/mL = 5 mL.
,8. Which antibiotic is known for its potential to cause tendon rupture, especially in older adults?
A) Ciprofloxacin
B) Amoxicillin
C) Azithromycin
D) Doxycycline
Answer: A) Ciprofloxacin
Rationale: Fluoroquinolones like ciprofloxacin can damage tendons, increasing rupture risk in
the elderly.
9. Which of the following is the antidote for acetaminophen overdose?
A) Naloxone
B) N-acetylcysteine
C) Flumazenil
D) Vitamin K
Answer: B) N-acetylcysteine
Rationale: N-acetylcysteine replenishes glutathione, helping to detoxify the harmful metabolite
of acetaminophen.
10. A patient experiences bradycardia and hypotension after administration of a beta-blocker.
Which of the following is most likely the cause?
A) Excessive beta-1 blockade
B) Excessive beta-2 blockade
C) ACE inhibition
D) Calcium channel blockade
Answer: A) Excessive beta-1 blockade
Rationale: Beta-blockers decrease heart rate and contractility by blocking beta-1 receptors in the
heart.
11. A patient taking digoxin is prescribed verapamil for hypertension. What is the most likely
interaction?
A) Increased digoxin clearance
B) Decreased digoxin clearance
C) No interaction
D) Increased digoxin excretion
Answer: B) Decreased digoxin clearance
Rationale: Verapamil decreases digoxin clearance, raising the risk for digoxin toxicity.
, 12. Which of the following conditions is a contraindication for the use of thiazide diuretics?
A) Hyperkalemia
B) Hypokalemia
C) Gout
D) Hyponatremia
Answer: C) Gout
Rationale: Thiazides can elevate uric acid levels, potentially precipitating gout attacks.
13. Which of the following is the mechanism of action of statins?
A) Inhibit cholesterol absorption in the gut
B) Inhibit HMG-CoA reductase
C) Increase LDL receptor expression
D) Inhibit bile acid reabsorption
Answer: B) Inhibit HMG-CoA reductase
Rationale: Statins reduce cholesterol synthesis by blocking HMG-CoA reductase.
14. Which anticoagulant requires monitoring of the INR for dose adjustments?
A) Heparin
B) Enoxaparin
C) Warfarin
D) Dabigatran
Answer: C) Warfarin
Rationale: Warfarin’s narrow therapeutic index necessitates regular INR monitoring.
15. Which drug is commonly used as a first-line treatment for type 2 diabetes mellitus?
A) Insulin
B) Metformin
C) Sulfonylureas
D) Thiazolidinediones
Answer: B) Metformin
Rationale: Metformin is the preferred initial therapy for type 2 diabetes because of its
effectiveness and favorable safety profile.
16. In a calculation, if a patient requires 0.8 mg/kg of a medication and weighs 75 kg, what is the
total dose?
A) 50 mg
