Lehne's Pharmacology for Nursing
Care
12th Edition
• Author(s)Jacqueline Rosenjack
Burchum; Laura D. Rosenthal
,TEST BANK
QUESTION 1
Question Type: MCQ
Clinical Scenario:
A 72-year-old patient with chronic heart failure is being
discharged with a new prescription for digoxin. The patient has
a history of renal impairment (estimated GFR 45
mL/min/1.73m²) and takes furosemide 40 mg daily.
Question Stem:
The nurse recognizes that which baseline assessment is most
critical to obtain prior to administering the first dose of digoxin?
Answer Options:
A. Serum potassium level
B. Complete blood count
C. Liver function tests
D. Serum creatinine level
Correct Answer: A. Serum potassium level
Detailed Rationale:
Pharmacologic Principles: Digoxin is a cardiac glycoside that
inhibits the Na⁺/K⁺-ATPase pump, increasing intracellular
calcium and enhancing myocardial contractility. The therapeutic
,index of digoxin is narrow, and its effects are highly dependent
on electrolyte balance.
Mechanism of Action: Digoxin's therapeutic and toxic effects
are potentiated by hypokalemia because potassium competes
with digoxin for binding sites on the Na⁺/K⁺-ATPase pump.
When serum potassium is low, more digoxin binds to the pump,
increasing the risk of toxicity even at therapeutic serum levels.
Nursing Implications: This patient is at particular risk for
hypokalemia due to concurrent furosemide therapy, which is a
loop diuretic that promotes potassium excretion. In the
presence of renal impairment, digoxin clearance is reduced,
further increasing toxicity risk. Baseline potassium assessment
allows the healthcare provider to correct hypokalemia before
initiating therapy, potentially preventing life-threatening
dysrhythmias.
Incorrect Option Analysis:
B. Complete blood count:
Why It Is Incorrect: While a CBC provides valuable health
information, it is not specifically indicated before digoxin
initiation.
Common Clinical Misconception: Thinking all baseline labs are
equally important for all medications.
Potential Medication Safety Risk: Missing critical electrolyte
imbalances could lead to digoxin toxicity.
, Appropriate Nursing Consideration: CBC may be relevant for
other medications but not specifically for digoxin.
C. Liver function tests:
Why It Is Incorrect: Digoxin is primarily eliminated by the
kidneys, not the liver. Liver function is not the primary concern
with digoxin administration.
Common Clinical Misconception: Assuming all medications
require liver function assessment.
Potential Medication Safety Risk: Focusing on liver function
could distract from critical renal and electrolyte assessments.
Appropriate Nursing Consideration: Liver function is important
for hepatically metabolized drugs, but digoxin is not significantly
metabolized by the liver.
D. Serum creatinine level:
Why It Is Incorrect: While renal function is important for digoxin
dosing, the GFR (estimated from serum creatinine) is already
known and is not the most critical immediate assessment.
Common Clinical Misconception: Assuming renal function is the
only factor affecting digoxin safety.
Potential Medication Safety Risk: Overlooking electrolyte
imbalances that may be more immediately life-threatening.
Appropriate Nursing Consideration: Renal function guides
maintenance dosing, but electrolyte status is more immediately
critical for patient safety.
Care
12th Edition
• Author(s)Jacqueline Rosenjack
Burchum; Laura D. Rosenthal
,TEST BANK
QUESTION 1
Question Type: MCQ
Clinical Scenario:
A 72-year-old patient with chronic heart failure is being
discharged with a new prescription for digoxin. The patient has
a history of renal impairment (estimated GFR 45
mL/min/1.73m²) and takes furosemide 40 mg daily.
Question Stem:
The nurse recognizes that which baseline assessment is most
critical to obtain prior to administering the first dose of digoxin?
Answer Options:
A. Serum potassium level
B. Complete blood count
C. Liver function tests
D. Serum creatinine level
Correct Answer: A. Serum potassium level
Detailed Rationale:
Pharmacologic Principles: Digoxin is a cardiac glycoside that
inhibits the Na⁺/K⁺-ATPase pump, increasing intracellular
calcium and enhancing myocardial contractility. The therapeutic
,index of digoxin is narrow, and its effects are highly dependent
on electrolyte balance.
Mechanism of Action: Digoxin's therapeutic and toxic effects
are potentiated by hypokalemia because potassium competes
with digoxin for binding sites on the Na⁺/K⁺-ATPase pump.
When serum potassium is low, more digoxin binds to the pump,
increasing the risk of toxicity even at therapeutic serum levels.
Nursing Implications: This patient is at particular risk for
hypokalemia due to concurrent furosemide therapy, which is a
loop diuretic that promotes potassium excretion. In the
presence of renal impairment, digoxin clearance is reduced,
further increasing toxicity risk. Baseline potassium assessment
allows the healthcare provider to correct hypokalemia before
initiating therapy, potentially preventing life-threatening
dysrhythmias.
Incorrect Option Analysis:
B. Complete blood count:
Why It Is Incorrect: While a CBC provides valuable health
information, it is not specifically indicated before digoxin
initiation.
Common Clinical Misconception: Thinking all baseline labs are
equally important for all medications.
Potential Medication Safety Risk: Missing critical electrolyte
imbalances could lead to digoxin toxicity.
, Appropriate Nursing Consideration: CBC may be relevant for
other medications but not specifically for digoxin.
C. Liver function tests:
Why It Is Incorrect: Digoxin is primarily eliminated by the
kidneys, not the liver. Liver function is not the primary concern
with digoxin administration.
Common Clinical Misconception: Assuming all medications
require liver function assessment.
Potential Medication Safety Risk: Focusing on liver function
could distract from critical renal and electrolyte assessments.
Appropriate Nursing Consideration: Liver function is important
for hepatically metabolized drugs, but digoxin is not significantly
metabolized by the liver.
D. Serum creatinine level:
Why It Is Incorrect: While renal function is important for digoxin
dosing, the GFR (estimated from serum creatinine) is already
known and is not the most critical immediate assessment.
Common Clinical Misconception: Assuming renal function is the
only factor affecting digoxin safety.
Potential Medication Safety Risk: Overlooking electrolyte
imbalances that may be more immediately life-threatening.
Appropriate Nursing Consideration: Renal function guides
maintenance dosing, but electrolyte status is more immediately
critical for patient safety.
