Pharmacology and the Nursing
Process
10th Edition
• Author(s)Linda Lane Lilley;
Shelly Rainforth Collins; Julie
S. Snyder
Question 1
Item Type: MCQ
,Clinical Scenario:
A 72-year-old patient with heart failure and moderate hepatic
impairment is prescribed digoxin 0.125 mg orally daily. The
nurse reviews the patient's medication history and notes
concurrent use of furosemide and lisinopril. The patient has a
serum creatinine of 1.8 mg/dL and an albumin level of 2.9 g/dL.
Question Stem:
Based on this patient's clinical presentation, which
pharmacokinetic alteration most significantly increases the risk
for digoxin toxicity?
Answer Options:
A. Increased drug absorption due to decreased gastrointestinal
motility
B. Reduced first-pass metabolism resulting in higher
bioavailability
C. Decreased protein binding leading to increased free drug
concentration
D. Enhanced renal excretion due to concurrent diuretic therapy
Correct Answer: C. Decreased protein binding leading to
increased free drug concentration
Comprehensive Rationale:
Digoxin is approximately 25% protein-bound, primarily to
albumin . In this patient, the low albumin level (2.9 g/dL,
normal 3.5-5.0 g/dL) indicates hypoalbuminemia, which
,reduces protein-binding sites available for digoxin. This results
in a higher fraction of unbound (free) active drug in the
circulation. The free drug is pharmacologically active and can
distribute to target tissues, including cardiac muscle .
Additionally, the patient's renal impairment (creatinine 1.8
mg/dL) reduces digoxin excretion, further compounding the risk
of toxicity. Advanced age (72 years) also contributes to
decreased renal function and altered volume of distribution.
The therapeutic index of digoxin is narrow (0.8-2.0 ng/mL),
making this patient particularly vulnerable to toxicity. The nurse
should monitor for signs of digoxin toxicity including nausea,
visual disturbances (yellow-green halos), and cardiac
dysrhythmias.
Distractor Analysis:
• Option A (Incorrect): While aging can decrease GI motility,
digoxin absorption from the GI tract is generally complete
and reliable. This is less clinically significant in this scenario
compared to protein-binding and excretion issues.
• Option B (Incorrect): Digoxin undergoes minimal first-pass
metabolism; it is primarily excreted unchanged by the
kidneys. The hepatic impairment would have less impact
on digoxin compared to drugs with extensive first-pass
metabolism.
, • Option D (Incorrect): Furosemide does not enhance
digoxin excretion; in fact, diuretics can cause electrolyte
imbalances (hypokalemia, hypomagnesemia) that increase
the heart's sensitivity to digoxin, potentially precipitating
toxicity.
Nursing Process Integration:
• Primary Component: Assessment – The nurse must assess
for factors affecting drug pharmacokinetics including renal
function, albumin levels, age, and concurrent medications.
• Assessment: Complete medication reconciliation,
laboratory data review, and physical assessment for signs
of digoxin toxicity.
• Implementation: Monitor serum digoxin levels, renal
function, electrolytes, and cardiac status.
Clinical Judgment Measurement Model (NCJMM):
• Recognize Cues
• Analyze Cues
• Prioritize Hypotheses
• Generate Solutions
Difficulty Level: Moderate
Bloom's Cognitive Level: Analyze
Process
10th Edition
• Author(s)Linda Lane Lilley;
Shelly Rainforth Collins; Julie
S. Snyder
Question 1
Item Type: MCQ
,Clinical Scenario:
A 72-year-old patient with heart failure and moderate hepatic
impairment is prescribed digoxin 0.125 mg orally daily. The
nurse reviews the patient's medication history and notes
concurrent use of furosemide and lisinopril. The patient has a
serum creatinine of 1.8 mg/dL and an albumin level of 2.9 g/dL.
Question Stem:
Based on this patient's clinical presentation, which
pharmacokinetic alteration most significantly increases the risk
for digoxin toxicity?
Answer Options:
A. Increased drug absorption due to decreased gastrointestinal
motility
B. Reduced first-pass metabolism resulting in higher
bioavailability
C. Decreased protein binding leading to increased free drug
concentration
D. Enhanced renal excretion due to concurrent diuretic therapy
Correct Answer: C. Decreased protein binding leading to
increased free drug concentration
Comprehensive Rationale:
Digoxin is approximately 25% protein-bound, primarily to
albumin . In this patient, the low albumin level (2.9 g/dL,
normal 3.5-5.0 g/dL) indicates hypoalbuminemia, which
,reduces protein-binding sites available for digoxin. This results
in a higher fraction of unbound (free) active drug in the
circulation. The free drug is pharmacologically active and can
distribute to target tissues, including cardiac muscle .
Additionally, the patient's renal impairment (creatinine 1.8
mg/dL) reduces digoxin excretion, further compounding the risk
of toxicity. Advanced age (72 years) also contributes to
decreased renal function and altered volume of distribution.
The therapeutic index of digoxin is narrow (0.8-2.0 ng/mL),
making this patient particularly vulnerable to toxicity. The nurse
should monitor for signs of digoxin toxicity including nausea,
visual disturbances (yellow-green halos), and cardiac
dysrhythmias.
Distractor Analysis:
• Option A (Incorrect): While aging can decrease GI motility,
digoxin absorption from the GI tract is generally complete
and reliable. This is less clinically significant in this scenario
compared to protein-binding and excretion issues.
• Option B (Incorrect): Digoxin undergoes minimal first-pass
metabolism; it is primarily excreted unchanged by the
kidneys. The hepatic impairment would have less impact
on digoxin compared to drugs with extensive first-pass
metabolism.
, • Option D (Incorrect): Furosemide does not enhance
digoxin excretion; in fact, diuretics can cause electrolyte
imbalances (hypokalemia, hypomagnesemia) that increase
the heart's sensitivity to digoxin, potentially precipitating
toxicity.
Nursing Process Integration:
• Primary Component: Assessment – The nurse must assess
for factors affecting drug pharmacokinetics including renal
function, albumin levels, age, and concurrent medications.
• Assessment: Complete medication reconciliation,
laboratory data review, and physical assessment for signs
of digoxin toxicity.
• Implementation: Monitor serum digoxin levels, renal
function, electrolytes, and cardiac status.
Clinical Judgment Measurement Model (NCJMM):
• Recognize Cues
• Analyze Cues
• Prioritize Hypotheses
• Generate Solutions
Difficulty Level: Moderate
Bloom's Cognitive Level: Analyze
