NAPLEX Exam V3 | North American
Pharmacist Licensure Examination
(NAPLEX) | Q&A with Rationale (NAPLEX
Exam) | National Association of Boards of
Pharmacy (NABP)
1. A 64-year-old male with a history of heart failure and hypertension is initiated on Lisinopril.
Which of the following electrolyte imbalances is most likely to occur?
A. Hypokalemia
B. Hyperkalemia
C. Hyponatremia
D. Hypercalcemia
Correct Answer: B
Rationale: Lisinopril is an ACE inhibitor that works by blocking the conversion of
Angiotensin I to Angiotensin II, which subsequently reduces aldosterone secretion. This
reduction in aldosterone leads to potassium retention in the kidneys, potentially causing
hyperkalemia. Pharmacists must monitor serum potassium and renal function closely
when initiating therapy or increasing the dose of any ACE inhibitor.
2. Which of the following medications is considered the gold standard for treating a patient
with a documented HLA-B*5701 allele mutation to prevent hypersensitivity reactions?
A. Tenofovir
,B. Abacavir
C. Lamivudine
D. Efavirenz
Correct Answer: B
Rationale: Abacavir is associated with a serious and potentially fatal hypersensitivity
reaction in patients who carry the HLA-B*5701 genetic marker. Current clinical guidelines
from the NABP and other health organizations mandate screening for this allele before
starting any abacavir-containing regimen. If a patient tests positive, abacavir is
contraindicated and should be permanently avoided in their treatment plan.
3. A patient is prescribed Warfarin for atrial fibrillation. Which of the following foods should
the patient be advised to maintain a consistent intake of to avoid fluctuations in their INR?
A. Grapefruit
B. Dairy Products
C. Red Meat
D. Spinach
Correct Answer: D
Rationale: Spinach is high in Vitamin K, which acts as a direct antagonist to the mechanism
of action of Warfarin. Significant changes in the amount of Vitamin K consumed can lead to
a decrease or increase in the INR, potentially causing clots or bleeding. Patients are advised
, to keep their dietary intake of green leafy vegetables consistent rather than eliminating
them entirely.
4. Which of the following describes the mechanism of action of Rivaroxaban?
A. Factor Xa Inhibitor
B. Direct Thrombin Inhibitor
C. Vitamin K Antagonist
D. ADP Receptor Antagonist
Correct Answer: A
Rationale: Rivaroxaban is an oral anticoagulant that works by selectively and reversibly
inhibiting Factor Xa. By blocking Factor Xa, the drug prevents the conversion of
prothrombin to thrombin, thereby inhibiting fibrin clot formation. Unlike warfarin, it does
not require routine INR monitoring but requires dose adjustment in renal impairment.
5. Calculate the Number Needed to Treat (NNT) if a new drug reduces the incidence of stroke
from 5% in the placebo group to 2% in the treatment group.
A. 20
B. 50
C. 33
D. 100
Correct Answer: C
Pharmacist Licensure Examination
(NAPLEX) | Q&A with Rationale (NAPLEX
Exam) | National Association of Boards of
Pharmacy (NABP)
1. A 64-year-old male with a history of heart failure and hypertension is initiated on Lisinopril.
Which of the following electrolyte imbalances is most likely to occur?
A. Hypokalemia
B. Hyperkalemia
C. Hyponatremia
D. Hypercalcemia
Correct Answer: B
Rationale: Lisinopril is an ACE inhibitor that works by blocking the conversion of
Angiotensin I to Angiotensin II, which subsequently reduces aldosterone secretion. This
reduction in aldosterone leads to potassium retention in the kidneys, potentially causing
hyperkalemia. Pharmacists must monitor serum potassium and renal function closely
when initiating therapy or increasing the dose of any ACE inhibitor.
2. Which of the following medications is considered the gold standard for treating a patient
with a documented HLA-B*5701 allele mutation to prevent hypersensitivity reactions?
A. Tenofovir
,B. Abacavir
C. Lamivudine
D. Efavirenz
Correct Answer: B
Rationale: Abacavir is associated with a serious and potentially fatal hypersensitivity
reaction in patients who carry the HLA-B*5701 genetic marker. Current clinical guidelines
from the NABP and other health organizations mandate screening for this allele before
starting any abacavir-containing regimen. If a patient tests positive, abacavir is
contraindicated and should be permanently avoided in their treatment plan.
3. A patient is prescribed Warfarin for atrial fibrillation. Which of the following foods should
the patient be advised to maintain a consistent intake of to avoid fluctuations in their INR?
A. Grapefruit
B. Dairy Products
C. Red Meat
D. Spinach
Correct Answer: D
Rationale: Spinach is high in Vitamin K, which acts as a direct antagonist to the mechanism
of action of Warfarin. Significant changes in the amount of Vitamin K consumed can lead to
a decrease or increase in the INR, potentially causing clots or bleeding. Patients are advised
, to keep their dietary intake of green leafy vegetables consistent rather than eliminating
them entirely.
4. Which of the following describes the mechanism of action of Rivaroxaban?
A. Factor Xa Inhibitor
B. Direct Thrombin Inhibitor
C. Vitamin K Antagonist
D. ADP Receptor Antagonist
Correct Answer: A
Rationale: Rivaroxaban is an oral anticoagulant that works by selectively and reversibly
inhibiting Factor Xa. By blocking Factor Xa, the drug prevents the conversion of
prothrombin to thrombin, thereby inhibiting fibrin clot formation. Unlike warfarin, it does
not require routine INR monitoring but requires dose adjustment in renal impairment.
5. Calculate the Number Needed to Treat (NNT) if a new drug reduces the incidence of stroke
from 5% in the placebo group to 2% in the treatment group.
A. 20
B. 50
C. 33
D. 100
Correct Answer: C
