NCLEX-RN Pharmacology Neurological
System Part 1 Exam Questions &
Rationales
20 Original Practice MCQs
ATI & NGN Style Nursing Test Bank
Question 1
Clinical Scenario
A 68-year-old man with newly diagnosed focal seizures is
admitted after experiencing two seizure episodes within 24
hours. His medical history includes hypertension and chronic
atrial fibrillation treated with warfarin. The provider prescribes
phenytoin. Baseline laboratory results include INR 2.5, albumin
3.1 g/dL, AST 28 U/L, and ALT 30 U/L. The nurse reviews the
medication profile before administering the first dose.
Question Stem
,Which nursing action is the highest priority before
administering the medication?
A. Administer the medication with milk to decrease gastric
irritation.
B. Notify the provider that phenytoin may alter the
effectiveness of warfarin.
C. Hold the medication because the client's INR is therapeutic.
D. Instruct the client to discontinue the medication if gum
swelling develops.
Correct Answer
Correct Answer: B. Notify the provider that phenytoin may
alter the effectiveness of warfarin.
Detailed Rationale
Phenytoin is a hepatic enzyme inducer that can significantly
alter the metabolism of numerous medications, including
warfarin. The interaction between phenytoin and warfarin is
clinically complex because phenytoin may initially increase
warfarin concentrations by protein-binding displacement,
followed by enhanced hepatic metabolism that reduces
anticoagulant effectiveness over time. These changes can
increase the risk for bleeding or thromboembolic complications,
making close INR monitoring and possible dosage adjustments
,necessary. Recognizing this interaction before therapy begins is
an essential medication safety responsibility.
Option A is incorrect because phenytoin should not routinely be
administered with dairy products if they interfere with
absorption, and this does not address the most important
safety issue. Option C is incorrect because a therapeutic INR is
not a contraindication to initiating phenytoin. Option D is
incorrect because gingival hyperplasia is a common adverse
effect requiring oral hygiene and provider notification rather
than abrupt discontinuation, which may precipitate seizures.
The nurse should also monitor serum phenytoin concentrations,
neurologic status, liver function, and signs of toxicity such as
nystagmus, ataxia, and confusion. Patient education should
include adherence, avoidance of abrupt discontinuation, and
reporting skin rash suggestive of severe hypersensitivity
reactions.
Learning Objectives
After completing this question, the learner should be able to:
• Identify clinically significant interactions between
phenytoin and warfarin.
• Prioritize medication reconciliation before initiating
antiepileptic therapy.
, • Recognize appropriate monitoring parameters during
phenytoin therapy.
Medication Safety Focus
Drug interaction
Question 2
Clinical Scenario
A 24-year-old woman with epilepsy has been taking valproic
acid for two years. She presents to the outpatient clinic
reporting persistent nausea, fatigue, loss of appetite, and right
upper quadrant abdominal discomfort. Laboratory results
reveal AST 168 U/L and ALT 185 U/L.
Question Stem
Which action should the nurse take first?
A. Recommend taking the medication with meals.
B. Instruct the client to increase fluid intake.
C. Notify the provider immediately about possible
hepatotoxicity.
D. Reassure the client that these findings are expected during
therapy.
Correct Answer
System Part 1 Exam Questions &
Rationales
20 Original Practice MCQs
ATI & NGN Style Nursing Test Bank
Question 1
Clinical Scenario
A 68-year-old man with newly diagnosed focal seizures is
admitted after experiencing two seizure episodes within 24
hours. His medical history includes hypertension and chronic
atrial fibrillation treated with warfarin. The provider prescribes
phenytoin. Baseline laboratory results include INR 2.5, albumin
3.1 g/dL, AST 28 U/L, and ALT 30 U/L. The nurse reviews the
medication profile before administering the first dose.
Question Stem
,Which nursing action is the highest priority before
administering the medication?
A. Administer the medication with milk to decrease gastric
irritation.
B. Notify the provider that phenytoin may alter the
effectiveness of warfarin.
C. Hold the medication because the client's INR is therapeutic.
D. Instruct the client to discontinue the medication if gum
swelling develops.
Correct Answer
Correct Answer: B. Notify the provider that phenytoin may
alter the effectiveness of warfarin.
Detailed Rationale
Phenytoin is a hepatic enzyme inducer that can significantly
alter the metabolism of numerous medications, including
warfarin. The interaction between phenytoin and warfarin is
clinically complex because phenytoin may initially increase
warfarin concentrations by protein-binding displacement,
followed by enhanced hepatic metabolism that reduces
anticoagulant effectiveness over time. These changes can
increase the risk for bleeding or thromboembolic complications,
making close INR monitoring and possible dosage adjustments
,necessary. Recognizing this interaction before therapy begins is
an essential medication safety responsibility.
Option A is incorrect because phenytoin should not routinely be
administered with dairy products if they interfere with
absorption, and this does not address the most important
safety issue. Option C is incorrect because a therapeutic INR is
not a contraindication to initiating phenytoin. Option D is
incorrect because gingival hyperplasia is a common adverse
effect requiring oral hygiene and provider notification rather
than abrupt discontinuation, which may precipitate seizures.
The nurse should also monitor serum phenytoin concentrations,
neurologic status, liver function, and signs of toxicity such as
nystagmus, ataxia, and confusion. Patient education should
include adherence, avoidance of abrupt discontinuation, and
reporting skin rash suggestive of severe hypersensitivity
reactions.
Learning Objectives
After completing this question, the learner should be able to:
• Identify clinically significant interactions between
phenytoin and warfarin.
• Prioritize medication reconciliation before initiating
antiepileptic therapy.
, • Recognize appropriate monitoring parameters during
phenytoin therapy.
Medication Safety Focus
Drug interaction
Question 2
Clinical Scenario
A 24-year-old woman with epilepsy has been taking valproic
acid for two years. She presents to the outpatient clinic
reporting persistent nausea, fatigue, loss of appetite, and right
upper quadrant abdominal discomfort. Laboratory results
reveal AST 168 U/L and ALT 185 U/L.
Question Stem
Which action should the nurse take first?
A. Recommend taking the medication with meals.
B. Instruct the client to increase fluid intake.
C. Notify the provider immediately about possible
hepatotoxicity.
D. Reassure the client that these findings are expected during
therapy.
Correct Answer
