MN 553 FINAL EXAM 1 – ADVANCED
PHARMACOLOGY FOR NURSE PRACTITIONERS
Actual Exam | Complete Q&A with Rationales –
Pass Guaranteed - A+ Graded
Part 1 – How Drugs Move and Work (PK/PD + Interactions) (12
questions)
Q1: A 58-year-old patient with atrial fibrillation is started on warfarin 5 mg daily. You
counsel them to maintain consistent vitamin K intake. Three weeks later, their INR is
1.4. They mention they've been eating a large spinach salad daily because they "heard
leafy greens were healthy." What is your next step?
A. Increase the warfarin dose to 7.5 mg and recheck INR in one month
B. Tell them to stop all vegetables entirely while on warfarin
C. Counsel them to keep spinach intake consistent rather than eliminating it, then adjust
the warfarin dose gradually and recheck INR in 1–2 weeks [CORRECT]
D. Switch to apixaban immediately since the patient clearly cannot manage dietary
restrictions
,Rationale: The best answer is counseling consistent vitamin K intake rather than
elimination. Warfarin dosing depends on stable vitamin K levels—sudden increases or
decreases both cause problems. Once intake is steady, you can titrate the warfarin dose
to match. Abruptly stopping vegetables or switching anticoagulants over a manageable
dietary issue isn't necessary.
Correct Answer: C
Q2: A patient on phenytoin for seizure control has been adherent for years. They start
rifampin for latent TB, and two weeks later they have a breakthrough seizure. What
pharmacokinetic mechanism explains this?
A. Rifampin inhibits phenytoin metabolism, causing toxicity that paradoxically triggers
seizures
B. Rifampin is a potent CYP450 inducer that increases phenytoin clearance, dropping
levels below therapeutic range [CORRECT]
C. Rifampin displaces phenytoin from albumin binding sites, increasing free drug and
causing neurotoxicity
D. The two drugs form an insoluble complex in the gut, reducing phenytoin absorption
Rationale: The best answer is CYP450 induction. Rifampin is one of the most powerful
enzyme inducers we have—it ramps up metabolism of many drugs, including phenytoin.
Phenytoin has a narrow therapeutic window, so even a modest drop in levels can lead to
breakthrough seizures. You'd need to increase the phenytoin dose and monitor levels
closely.
Correct Answer: B
,Q3: A 72-year-old with heart failure is started on digoxin 0.125 mg daily. She also takes
amiodarone for atrial fibrillation. Three weeks later she reports nausea, visual
disturbances with yellow halos around lights, and palpitations. Her digoxin level is 2.8
ng/mL. What interaction is at play here?
A. Amiodarone induces digoxin metabolism through CYP3A4, causing subtherapeutic
levels and withdrawal symptoms
B. Amiodarone inhibits P-glycoprotein and displaces digoxin from tissue binding,
increasing digoxin levels by 70–100% [CORRECT]
C. Digoxin inhibits amiodarone metabolism, leading to amiodarone toxicity that mimics
digoxin toxicity
D. The combination causes additive bradycardia that triggers compensatory tachycardia
and digoxin redistribution
Rationale: The best answer is P-glycoprotein inhibition. Amiodarone doesn't just mess
with CYP enzymes—it also knocks out P-gp, which is how digoxin gets out of tissues
and into the urine. Digoxin levels can essentially double. With a narrow therapeutic index
and toxicity signs starting around 2.0 ng/mL, this patient is in trouble. Hold the digoxin,
check potassium, and consider dose reduction when restarting.
Correct Answer: B
Q4: A patient asks why they need to take their levothyroxine first thing in the morning on
an empty stomach, 30–60 minutes before breakfast. What is the primary
pharmacokinetic reason?
A. Food increases gastric acid secretion, which chemically degrades levothyroxine
, B. Calcium, iron, and fiber in food form insoluble complexes that reduce absorption by
40–80% [CORRECT]
C. Food stimulates CYP3A4 in the gut wall, increasing first-pass metabolism of
levothyroxine
D. Levothyroxine requires an acidic environment for dissolution, and food buffers
stomach pH
Rationale: The best answer is chelation with food components. Calcium supplements,
iron, soy, and even coffee can dramatically cut levothyroxine absorption. Taking it on an
empty stomach with water gives you the most predictable bioavailability. If a patient
absolutely can't do mornings, bedtime dosing at least 3–4 hours after the last meal is a
reasonable alternative.
Correct Answer: B
Q5: A patient with bipolar disorder has been stable on lithium 900 mg BID for eight
months. They develop a UTI and are prescribed trimethoprim-sulfamethoxazole. What is
your primary concern regarding this combination?
A. TMP-SMX induces lithium metabolism, potentially causing manic relapse
B. TMP-SMX reduces lithium renal clearance by competing for proximal tubule
secretion, risking lithium toxicity [CORRECT]
C. The combination causes serotonin syndrome due to additive serotonergic effects
D. Lithium reduces SMX absorption, making the antibiotic ineffective for the UTI
Rationale: The best answer is reduced renal clearance. Lithium is entirely renally
excreted—no metabolism at all. Drugs that compete for tubular secretion or reduce GFR,
PHARMACOLOGY FOR NURSE PRACTITIONERS
Actual Exam | Complete Q&A with Rationales –
Pass Guaranteed - A+ Graded
Part 1 – How Drugs Move and Work (PK/PD + Interactions) (12
questions)
Q1: A 58-year-old patient with atrial fibrillation is started on warfarin 5 mg daily. You
counsel them to maintain consistent vitamin K intake. Three weeks later, their INR is
1.4. They mention they've been eating a large spinach salad daily because they "heard
leafy greens were healthy." What is your next step?
A. Increase the warfarin dose to 7.5 mg and recheck INR in one month
B. Tell them to stop all vegetables entirely while on warfarin
C. Counsel them to keep spinach intake consistent rather than eliminating it, then adjust
the warfarin dose gradually and recheck INR in 1–2 weeks [CORRECT]
D. Switch to apixaban immediately since the patient clearly cannot manage dietary
restrictions
,Rationale: The best answer is counseling consistent vitamin K intake rather than
elimination. Warfarin dosing depends on stable vitamin K levels—sudden increases or
decreases both cause problems. Once intake is steady, you can titrate the warfarin dose
to match. Abruptly stopping vegetables or switching anticoagulants over a manageable
dietary issue isn't necessary.
Correct Answer: C
Q2: A patient on phenytoin for seizure control has been adherent for years. They start
rifampin for latent TB, and two weeks later they have a breakthrough seizure. What
pharmacokinetic mechanism explains this?
A. Rifampin inhibits phenytoin metabolism, causing toxicity that paradoxically triggers
seizures
B. Rifampin is a potent CYP450 inducer that increases phenytoin clearance, dropping
levels below therapeutic range [CORRECT]
C. Rifampin displaces phenytoin from albumin binding sites, increasing free drug and
causing neurotoxicity
D. The two drugs form an insoluble complex in the gut, reducing phenytoin absorption
Rationale: The best answer is CYP450 induction. Rifampin is one of the most powerful
enzyme inducers we have—it ramps up metabolism of many drugs, including phenytoin.
Phenytoin has a narrow therapeutic window, so even a modest drop in levels can lead to
breakthrough seizures. You'd need to increase the phenytoin dose and monitor levels
closely.
Correct Answer: B
,Q3: A 72-year-old with heart failure is started on digoxin 0.125 mg daily. She also takes
amiodarone for atrial fibrillation. Three weeks later she reports nausea, visual
disturbances with yellow halos around lights, and palpitations. Her digoxin level is 2.8
ng/mL. What interaction is at play here?
A. Amiodarone induces digoxin metabolism through CYP3A4, causing subtherapeutic
levels and withdrawal symptoms
B. Amiodarone inhibits P-glycoprotein and displaces digoxin from tissue binding,
increasing digoxin levels by 70–100% [CORRECT]
C. Digoxin inhibits amiodarone metabolism, leading to amiodarone toxicity that mimics
digoxin toxicity
D. The combination causes additive bradycardia that triggers compensatory tachycardia
and digoxin redistribution
Rationale: The best answer is P-glycoprotein inhibition. Amiodarone doesn't just mess
with CYP enzymes—it also knocks out P-gp, which is how digoxin gets out of tissues
and into the urine. Digoxin levels can essentially double. With a narrow therapeutic index
and toxicity signs starting around 2.0 ng/mL, this patient is in trouble. Hold the digoxin,
check potassium, and consider dose reduction when restarting.
Correct Answer: B
Q4: A patient asks why they need to take their levothyroxine first thing in the morning on
an empty stomach, 30–60 minutes before breakfast. What is the primary
pharmacokinetic reason?
A. Food increases gastric acid secretion, which chemically degrades levothyroxine
, B. Calcium, iron, and fiber in food form insoluble complexes that reduce absorption by
40–80% [CORRECT]
C. Food stimulates CYP3A4 in the gut wall, increasing first-pass metabolism of
levothyroxine
D. Levothyroxine requires an acidic environment for dissolution, and food buffers
stomach pH
Rationale: The best answer is chelation with food components. Calcium supplements,
iron, soy, and even coffee can dramatically cut levothyroxine absorption. Taking it on an
empty stomach with water gives you the most predictable bioavailability. If a patient
absolutely can't do mornings, bedtime dosing at least 3–4 hours after the last meal is a
reasonable alternative.
Correct Answer: B
Q5: A patient with bipolar disorder has been stable on lithium 900 mg BID for eight
months. They develop a UTI and are prescribed trimethoprim-sulfamethoxazole. What is
your primary concern regarding this combination?
A. TMP-SMX induces lithium metabolism, potentially causing manic relapse
B. TMP-SMX reduces lithium renal clearance by competing for proximal tubule
secretion, risking lithium toxicity [CORRECT]
C. The combination causes serotonin syndrome due to additive serotonergic effects
D. Lithium reduces SMX absorption, making the antibiotic ineffective for the UTI
Rationale: The best answer is reduced renal clearance. Lithium is entirely renally
excreted—no metabolism at all. Drugs that compete for tubular secretion or reduce GFR,
