, Question 1
A patient receiving continuous IV heparin has an aPTT of 118 seconds
(therapeutic range 60-80 seconds) and new hematuria. Which action should the
nurse anticipate as the priority?
A. Administer vitamin K 10 mg IV push
B. Hold the heparin infusion and prepare protamine sulfate
C. Continue the infusion and recheck aPTT in 6 hours
D. Transfuse fresh frozen plasma and restart heparin at a higher rate
Correct Answer: B - Hold the heparin infusion and prepare
protamine sulfate
RATIONALE
A markedly supratherapeutic aPTT with bleeding requires stopping
heparin and administering protamine sulfate, its specific antidote.
Vitamin K reverses warfarin, not heparin; continuing the infusion
worsens bleeding risk; FFP is not first-line for heparin reversal.
Question 2
Which pharmacokinetic parameter is most directly altered by advanced chronic
kidney disease, necessitating dose reduction of renally eliminated drugs?
A. Volume of distribution
B. Bioavailability
C. Clearance
D. Protein binding affinity
Correct Answer: C - Clearance
RATIONALE
Renal impairment primarily reduces drug clearance, prolonging
elimination half-life and increasing accumulation risk. Volume of
distribution and bioavailability are less consistently affected, and
protein binding changes are variable and not the principal determinant
of dose adjustment.
Page 2
, Question 3
A patient prescribed warfarin is started on fluconazole for a fungal infection.
Which mechanism best explains the anticipated increase in INR?
A. Fluconazole induces CYP2C9, increasing warfarin metabolism
B. Fluconazole inhibits CYP2C9, reducing warfarin metabolism
C. Fluconazole displaces warfarin from albumin, increasing free drug
D. Fluconazole enhances vitamin K absorption, potentiating warfarin
Correct Answer: B - Fluconazole inhibits CYP2C9, reducing
warfarin metabolism
RATIONALE
Fluconazole is a potent inhibitor of CYP2C9, the enzyme that
metabolizes S-warfarin, leading to increased warfarin levels and INR.
Induction would decrease INR; protein displacement is transient and
not the primary mechanism; vitamin K enhancement would
antagonize warfarin.
Question 4
Which instruction is most critical for a patient starting sublingual nitroglycerin
for angina?
A. Swallow the tablet with water for faster absorption
B. Take one tablet every 5 minutes up to 3 doses; call 911 if pain persists
C. Take with a PDE5 inhibitor for synergistic relief
D. Store the tablets in a clear plastic pillbox for easy access
Correct Answer: B - Take one tablet every 5 minutes up to 3
doses; call 911 if pain persists
RATIONALE
Sublingual nitroglycerin should be taken every 5 minutes for up to 3
doses; if pain persists, emergency services should be activated.
Swallowing reduces efficacy; combining with PDE5 inhibitors causes
severe hypotension; light and moisture degrade the drug.
Page 3
, Question 5
A patient is prescribed digoxin and reports nausea, visual disturbances, and a
heart rate of 48 bpm. Which laboratory value is most important to assess?
A. Serum potassium
B. Serum sodium
C. Serum calcium
D. Serum magnesium
Correct Answer: A - Serum potassium
RATIONALE
Hypokalemia potentiates digoxin toxicity, and these symptoms
suggest toxicity. Potassium is the most critical electrolyte to evaluate.
Sodium, calcium, and magnesium are less directly implicated in
digoxin toxicity.
Question 6
Which statement best reflects the concept of a narrow therapeutic index (NTI)
drug?
A. Small changes in dose or blood level can cause therapeutic failure or
toxicity
B. The drug has a wide margin between therapeutic and toxic doses
C. The drug requires no routine monitoring of serum levels
D. The drug is safe in all patient populations without dose adjustment
Correct Answer: A - Small changes in dose or blood level can
cause therapeutic failure or toxicity
RATIONALE
NTI drugs have a small margin between effective and toxic
concentrations, so minor changes can lead to subtherapeutic or toxic
effects. They require therapeutic drug monitoring. The other options
describe opposite or incorrect characteristics.
Page 4
A patient receiving continuous IV heparin has an aPTT of 118 seconds
(therapeutic range 60-80 seconds) and new hematuria. Which action should the
nurse anticipate as the priority?
A. Administer vitamin K 10 mg IV push
B. Hold the heparin infusion and prepare protamine sulfate
C. Continue the infusion and recheck aPTT in 6 hours
D. Transfuse fresh frozen plasma and restart heparin at a higher rate
Correct Answer: B - Hold the heparin infusion and prepare
protamine sulfate
RATIONALE
A markedly supratherapeutic aPTT with bleeding requires stopping
heparin and administering protamine sulfate, its specific antidote.
Vitamin K reverses warfarin, not heparin; continuing the infusion
worsens bleeding risk; FFP is not first-line for heparin reversal.
Question 2
Which pharmacokinetic parameter is most directly altered by advanced chronic
kidney disease, necessitating dose reduction of renally eliminated drugs?
A. Volume of distribution
B. Bioavailability
C. Clearance
D. Protein binding affinity
Correct Answer: C - Clearance
RATIONALE
Renal impairment primarily reduces drug clearance, prolonging
elimination half-life and increasing accumulation risk. Volume of
distribution and bioavailability are less consistently affected, and
protein binding changes are variable and not the principal determinant
of dose adjustment.
Page 2
, Question 3
A patient prescribed warfarin is started on fluconazole for a fungal infection.
Which mechanism best explains the anticipated increase in INR?
A. Fluconazole induces CYP2C9, increasing warfarin metabolism
B. Fluconazole inhibits CYP2C9, reducing warfarin metabolism
C. Fluconazole displaces warfarin from albumin, increasing free drug
D. Fluconazole enhances vitamin K absorption, potentiating warfarin
Correct Answer: B - Fluconazole inhibits CYP2C9, reducing
warfarin metabolism
RATIONALE
Fluconazole is a potent inhibitor of CYP2C9, the enzyme that
metabolizes S-warfarin, leading to increased warfarin levels and INR.
Induction would decrease INR; protein displacement is transient and
not the primary mechanism; vitamin K enhancement would
antagonize warfarin.
Question 4
Which instruction is most critical for a patient starting sublingual nitroglycerin
for angina?
A. Swallow the tablet with water for faster absorption
B. Take one tablet every 5 minutes up to 3 doses; call 911 if pain persists
C. Take with a PDE5 inhibitor for synergistic relief
D. Store the tablets in a clear plastic pillbox for easy access
Correct Answer: B - Take one tablet every 5 minutes up to 3
doses; call 911 if pain persists
RATIONALE
Sublingual nitroglycerin should be taken every 5 minutes for up to 3
doses; if pain persists, emergency services should be activated.
Swallowing reduces efficacy; combining with PDE5 inhibitors causes
severe hypotension; light and moisture degrade the drug.
Page 3
, Question 5
A patient is prescribed digoxin and reports nausea, visual disturbances, and a
heart rate of 48 bpm. Which laboratory value is most important to assess?
A. Serum potassium
B. Serum sodium
C. Serum calcium
D. Serum magnesium
Correct Answer: A - Serum potassium
RATIONALE
Hypokalemia potentiates digoxin toxicity, and these symptoms
suggest toxicity. Potassium is the most critical electrolyte to evaluate.
Sodium, calcium, and magnesium are less directly implicated in
digoxin toxicity.
Question 6
Which statement best reflects the concept of a narrow therapeutic index (NTI)
drug?
A. Small changes in dose or blood level can cause therapeutic failure or
toxicity
B. The drug has a wide margin between therapeutic and toxic doses
C. The drug requires no routine monitoring of serum levels
D. The drug is safe in all patient populations without dose adjustment
Correct Answer: A - Small changes in dose or blood level can
cause therapeutic failure or toxicity
RATIONALE
NTI drugs have a small margin between effective and toxic
concentrations, so minor changes can lead to subtherapeutic or toxic
effects. They require therapeutic drug monitoring. The other options
describe opposite or incorrect characteristics.
Page 4
