Pharmacokinetics & Pharmacodynamics Actual Exam
2026/2027 – Complete Exam-Style Questions with Detailed
Rationales | 100% Verified | Pass Guaranteed – A+ Graded
Q1: A patient taking oral propranolol for hypertension has a significantly lower plasma
drug concentration than expected. The nurse discovers the patient has severe cirrhosis.
This reduced effect is most likely due to:
A. Decreased renal excretion of the drug
B. Increased first-pass metabolism in the liver
C. Decreased first-pass metabolism with altered bioavailability [CORRECT]
D. Increased protein binding in the bloodstream
Correct Answer: C
Rationale: Propranolol is a drug with extensive first-pass hepatic metabolism. In severe
cirrhosis, first-pass metabolism is decreased (not increased—B is incorrect), which
would actually increase bioavailability, not decrease it. However, in advanced liver
disease, hepatic blood flow is shunted past hepatocytes (portosystemic shunting), and
the overall metabolic capacity is severely compromised, leading to unpredictable
pharmacokinetics. The question describes lower-than-expected concentration, which
could result from altered absorption, decreased hepatic extraction, or increased volume
of distribution in edema. More importantly, the nurse must recognize that liver disease
fundamentally alters first-pass effects. Decreased renal excretion (A) would increase
levels. Increased protein binding (D) would decrease free drug but total concentration
would remain. The key concept is that liver disease disrupts first-pass metabolism
unpredictably. 100% VERIFIED – Rasmussen NUR2407
,Q2: A patient receiving IV morphine for post-operative pain requires dose adjustment
when switched to oral morphine tablets. The nurse understands that the oral dose must
be higher because:
A. Oral morphine has 100% bioavailability like IV morphine
B. Oral morphine undergoes first-pass hepatic metabolism, reducing the amount
reaching systemic circulation [CORRECT]
C. Oral morphine is absorbed more rapidly than IV morphine
D. Oral morphine has a larger volume of distribution than IV morphine
Correct Answer: B
Rationale: Oral morphine undergoes significant first-pass metabolism in the liver, with
bioavailability approximately 20-30% compared to 100% for IV administration.
Therefore, oral doses are typically 2-3 times higher than IV doses to achieve equivalent
systemic exposure. IV drugs have 100% bioavailability by definition (A is incorrect). Oral
absorption is slower, not faster, than IV (C is incorrect). Route of administration does
not change volume of distribution (D is incorrect). 100% VERIFIED – Rasmussen
NUR2407
Q3: A patient taking phenytoin for seizure control starts taking St. John's Wort for
depression. Two weeks later, the patient experiences breakthrough seizures. The nurse
recognizes this as:
A. An additive effect between the two medications
B. A synergistic interaction enhancing seizure control
C. CYP450 enzyme induction by St. John's Wort, increasing phenytoin metabolism and
decreasing its plasma concentration [CORRECT]
,D. CYP450 enzyme inhibition by St. John's Wort, increasing phenytoin toxicity
Correct Answer: C
Rationale: St. John's Wort is a potent CYP450 inducer (and P-glycoprotein inducer) that
increases the metabolism of many drugs, including phenytoin. Increased metabolism
decreases phenytoin plasma levels below the therapeutic range, causing breakthrough
seizures. Phenytoin itself is also a CYP450 inducer. This is an inductive, not inhibitory
(D), interaction. It is not additive (A) or synergistic (B)—it reduces, not enhances,
phenytoin effect. 100% VERIFIED – Rasmussen NUR2407
Q4: A patient with renal impairment (CrCl 25 mL/min) is prescribed gentamicin. The
nurse understands that this patient requires:
A. A standard dose with increased frequency
B. A reduced dose or extended dosing interval to prevent drug accumulation and
nephrotoxicity [CORRECT]
C. A loading dose only, with no maintenance doses
D. No dose adjustment since gentamicin is metabolized by the liver
Correct Answer: B
Rationale: Gentamicin is primarily eliminated unchanged by glomerular filtration. In renal
impairment, reduced clearance leads to prolonged half-life and drug accumulation,
increasing nephrotoxicity and ototoxicity risk. Dose reduction or extended intervals (e.g.,
once-daily vs. traditional divided dosing) are required. Standard dosing (A) would cause
toxicity. Loading dose only (C) is inappropriate for ongoing infection. Gentamicin is not
, hepatically metabolized (D)—it is renally excreted. 100% VERIFIED – Rasmussen
NUR2407
Q5: A patient taking warfarin consistently drinks grapefruit juice. The nurse should be
concerned about:
A. Decreased warfarin absorption due to grapefruit fiber content
B. CYP3A4 inhibition by grapefruit juice, potentially increasing warfarin plasma levels
and bleeding risk [CORRECT]
C. Increased vitamin K content in grapefruit juice antagonizing warfarin
D. CYP450 induction by grapefruit juice decreasing warfarin effectiveness
Correct Answer: B
Rationale: Grapefruit juice contains furanocoumarins that irreversibly inhibit intestinal
CYP3A4 (and P-glycoprotein), increasing bioavailability of substrates like warfarin,
statins, and calcium channel blockers. This inhibition can significantly increase warfarin
plasma levels and INR, elevating bleeding risk. It does not decrease absorption (A).
Grapefruit is not high in vitamin K (C). It inhibits, not induces (D), CYP450 enzymes.
100% VERIFIED – Rasmussen NUR2407
Q6: A patient with heart failure is prescribed digoxin. The nurse understands that
digoxin has a narrow therapeutic index. This means:
A. The drug has a wide safety margin between effective and toxic doses
B. The effective dose and toxic dose are very close, requiring careful monitoring of
plasma levels and clinical signs [CORRECT]
C. The drug is effective only at doses above the toxic threshold
2026/2027 – Complete Exam-Style Questions with Detailed
Rationales | 100% Verified | Pass Guaranteed – A+ Graded
Q1: A patient taking oral propranolol for hypertension has a significantly lower plasma
drug concentration than expected. The nurse discovers the patient has severe cirrhosis.
This reduced effect is most likely due to:
A. Decreased renal excretion of the drug
B. Increased first-pass metabolism in the liver
C. Decreased first-pass metabolism with altered bioavailability [CORRECT]
D. Increased protein binding in the bloodstream
Correct Answer: C
Rationale: Propranolol is a drug with extensive first-pass hepatic metabolism. In severe
cirrhosis, first-pass metabolism is decreased (not increased—B is incorrect), which
would actually increase bioavailability, not decrease it. However, in advanced liver
disease, hepatic blood flow is shunted past hepatocytes (portosystemic shunting), and
the overall metabolic capacity is severely compromised, leading to unpredictable
pharmacokinetics. The question describes lower-than-expected concentration, which
could result from altered absorption, decreased hepatic extraction, or increased volume
of distribution in edema. More importantly, the nurse must recognize that liver disease
fundamentally alters first-pass effects. Decreased renal excretion (A) would increase
levels. Increased protein binding (D) would decrease free drug but total concentration
would remain. The key concept is that liver disease disrupts first-pass metabolism
unpredictably. 100% VERIFIED – Rasmussen NUR2407
,Q2: A patient receiving IV morphine for post-operative pain requires dose adjustment
when switched to oral morphine tablets. The nurse understands that the oral dose must
be higher because:
A. Oral morphine has 100% bioavailability like IV morphine
B. Oral morphine undergoes first-pass hepatic metabolism, reducing the amount
reaching systemic circulation [CORRECT]
C. Oral morphine is absorbed more rapidly than IV morphine
D. Oral morphine has a larger volume of distribution than IV morphine
Correct Answer: B
Rationale: Oral morphine undergoes significant first-pass metabolism in the liver, with
bioavailability approximately 20-30% compared to 100% for IV administration.
Therefore, oral doses are typically 2-3 times higher than IV doses to achieve equivalent
systemic exposure. IV drugs have 100% bioavailability by definition (A is incorrect). Oral
absorption is slower, not faster, than IV (C is incorrect). Route of administration does
not change volume of distribution (D is incorrect). 100% VERIFIED – Rasmussen
NUR2407
Q3: A patient taking phenytoin for seizure control starts taking St. John's Wort for
depression. Two weeks later, the patient experiences breakthrough seizures. The nurse
recognizes this as:
A. An additive effect between the two medications
B. A synergistic interaction enhancing seizure control
C. CYP450 enzyme induction by St. John's Wort, increasing phenytoin metabolism and
decreasing its plasma concentration [CORRECT]
,D. CYP450 enzyme inhibition by St. John's Wort, increasing phenytoin toxicity
Correct Answer: C
Rationale: St. John's Wort is a potent CYP450 inducer (and P-glycoprotein inducer) that
increases the metabolism of many drugs, including phenytoin. Increased metabolism
decreases phenytoin plasma levels below the therapeutic range, causing breakthrough
seizures. Phenytoin itself is also a CYP450 inducer. This is an inductive, not inhibitory
(D), interaction. It is not additive (A) or synergistic (B)—it reduces, not enhances,
phenytoin effect. 100% VERIFIED – Rasmussen NUR2407
Q4: A patient with renal impairment (CrCl 25 mL/min) is prescribed gentamicin. The
nurse understands that this patient requires:
A. A standard dose with increased frequency
B. A reduced dose or extended dosing interval to prevent drug accumulation and
nephrotoxicity [CORRECT]
C. A loading dose only, with no maintenance doses
D. No dose adjustment since gentamicin is metabolized by the liver
Correct Answer: B
Rationale: Gentamicin is primarily eliminated unchanged by glomerular filtration. In renal
impairment, reduced clearance leads to prolonged half-life and drug accumulation,
increasing nephrotoxicity and ototoxicity risk. Dose reduction or extended intervals (e.g.,
once-daily vs. traditional divided dosing) are required. Standard dosing (A) would cause
toxicity. Loading dose only (C) is inappropriate for ongoing infection. Gentamicin is not
, hepatically metabolized (D)—it is renally excreted. 100% VERIFIED – Rasmussen
NUR2407
Q5: A patient taking warfarin consistently drinks grapefruit juice. The nurse should be
concerned about:
A. Decreased warfarin absorption due to grapefruit fiber content
B. CYP3A4 inhibition by grapefruit juice, potentially increasing warfarin plasma levels
and bleeding risk [CORRECT]
C. Increased vitamin K content in grapefruit juice antagonizing warfarin
D. CYP450 induction by grapefruit juice decreasing warfarin effectiveness
Correct Answer: B
Rationale: Grapefruit juice contains furanocoumarins that irreversibly inhibit intestinal
CYP3A4 (and P-glycoprotein), increasing bioavailability of substrates like warfarin,
statins, and calcium channel blockers. This inhibition can significantly increase warfarin
plasma levels and INR, elevating bleeding risk. It does not decrease absorption (A).
Grapefruit is not high in vitamin K (C). It inhibits, not induces (D), CYP450 enzymes.
100% VERIFIED – Rasmussen NUR2407
Q6: A patient with heart failure is prescribed digoxin. The nurse understands that
digoxin has a narrow therapeutic index. This means:
A. The drug has a wide safety margin between effective and toxic doses
B. The effective dose and toxic dose are very close, requiring careful monitoring of
plasma levels and clinical signs [CORRECT]
C. The drug is effective only at doses above the toxic threshold
