NR 565 ADVANCED PHARMACOLOGY FUNDAMENTALS
FINAL EXAM STUDY GUIDE 2026/2027 | Latest Chamberlain
College Complete Prep | Pass Guaranteed - A+ Graded
UNIT 1: PHARMACOKINETICS & PHARMACODYNAMICS (15 Questions)
Q1: A 68-year-old male with atrial fibrillation (CHADS₂-VASc score 4) is initiated on
warfarin 5 mg daily. His baseline INR is 1.0. Pharmacogenomic testing reveals CYP2C9
*1/*3 and VKORC1 -1639 G/A genotypes. On day 5, his INR is 1.8. Based on
pharmacokinetic principles and genotype-guided dosing, what is the most appropriate
next step?
A. Continue 5 mg daily and recheck INR in 1 week
B. Increase to 7.5 mg daily due to subtherapeutic INR
C. Continue 5 mg daily; therapeutic steady state requires 7-10 days due to long half-life
of clotting factors and his intermediate metabolizer status [CORRECT]
D. Decrease to 2.5 mg daily due to VKORC1 variant predicting warfarin sensitivity
Correct Answer: C
,Rationale: Warfarin's pharmacodynamic effect depends on depletion of vitamin
K-dependent clotting factors (II, VII, IX, X) with varying half-lives (6-60 hours). Factor II
(prothrombin) has the longest half-life (~60 hours), making 5-7 days necessary to
achieve steady-state anticoagulation regardless of warfarin plasma concentrations. The
patient carries CYP2C9 *1/*3 (intermediate metabolizer) and VKORC1 -1639 G/A
(intermediate sensitivity), suggesting slightly reduced warfarin requirements, but the
current INR of 1.8 on day 5 represents appropriate progression toward therapeutic
range (2.0-3.0 for AF). Option A delays appropriate monitoring; Option B risks
overshooting therapeutic range; Option D is premature given current subtherapeutic
status and would cause therapeutic delay.
Q2: A 45-year-old female with complex partial seizures is prescribed phenytoin 300 mg
daily. She has albumin 2.8 g/dL (normal 3.5-5.0). Her total phenytoin level is 12 mcg/mL
(therapeutic 10-20). What is the most accurate assessment of her pharmacokinetic
status?
A. Therapeutic; continue current dose
B. Subtherapeutic; increase dose to achieve 15-20 mcg/mL total level
C. Likely toxic; phenytoin is highly protein-bound and hypoalbuminemia increases free
fraction [CORRECT]
D. Requires immediate discontinuation due to severe toxicity
Correct Answer: C
,Rationale: Phenytoin is 90% protein-bound, primarily to albumin. In hypoalbuminemia,
the free fraction increases from ~10% to 15-20%, dramatically increasing
pharmacologic effect despite "normal" total levels. The corrected phenytoin level =
measured level / [(0.25 × albumin) + 0.1] = 12 / [(0.25 × 2.8) + 0.1] = .8 = 15
mcg/mL equivalent. However, free phenytoin levels (therapeutic 1-2 mcg/mL) would
likely exceed 2 mcg/mL, indicating neurotoxicity risk. Option A ignores protein-binding
alterations; Option B would cause definite toxicity; Option D is excessive without clinical
toxicity signs.
Q3: A 55-year-old male with HIV (CD4 200) starts efavirenz-based ART. He reports vivid
dreams and dizziness. Pharmacokinetically, which principle explains these early
adverse effects?
A. CYP3A4 inhibition causing drug accumulation
B. CNS penetration and long half-life (40-55 hours) with steady-state accumulation
[CORRECT]
C. Rapid distribution to adipose tissue causing delayed CNS effects
D. P-glycoprotein efflux preventing CNS penetration
Correct Answer: B
Rationale: Efavirenz is a lipophilic non-nucleoside reverse transcriptase inhibitor
(NNRTI) with excellent CNS penetration and long elimination half-life (40-55 hours).
, Adverse CNS effects (vivid dreams, dizziness, confusion) occur in 50% of patients
during first 2-4 weeks due to accumulation toward steady state, which requires ~5
half-lives (8-11 days). These effects typically resolve after 2-4 weeks despite continued
therapy. Option A is incorrect—efavirenz induces CYP3A4; Option C is
backwards—lipophilic drugs distribute to fat, but CNS effects occur rapidly due to high
brain penetration; Option D is incorrect—efavirenz crosses the blood-brain barrier
effectively.
Q4: For a drug following first-order kinetics with half-life of 6 hours, approximately what
percentage remains after 24 hours?
A. 6.25% [CORRECT]
B. 12.5%
C. 25%
D. 50%
Correct Answer: A
Rationale: First-order elimination: constant percentage eliminated per unit time. After n
half-lives, remaining drug = (1/2)ⁿ × 100%. Twenty-four hours = 4 half-lives (24/6).
Remaining = (1/2)⁴ × 100% = 1/16 × 100% = 6.25%. Option B represents 3 half-lives;
Option C represents 2 half-lives; Option D represents 1 half-life.
FINAL EXAM STUDY GUIDE 2026/2027 | Latest Chamberlain
College Complete Prep | Pass Guaranteed - A+ Graded
UNIT 1: PHARMACOKINETICS & PHARMACODYNAMICS (15 Questions)
Q1: A 68-year-old male with atrial fibrillation (CHADS₂-VASc score 4) is initiated on
warfarin 5 mg daily. His baseline INR is 1.0. Pharmacogenomic testing reveals CYP2C9
*1/*3 and VKORC1 -1639 G/A genotypes. On day 5, his INR is 1.8. Based on
pharmacokinetic principles and genotype-guided dosing, what is the most appropriate
next step?
A. Continue 5 mg daily and recheck INR in 1 week
B. Increase to 7.5 mg daily due to subtherapeutic INR
C. Continue 5 mg daily; therapeutic steady state requires 7-10 days due to long half-life
of clotting factors and his intermediate metabolizer status [CORRECT]
D. Decrease to 2.5 mg daily due to VKORC1 variant predicting warfarin sensitivity
Correct Answer: C
,Rationale: Warfarin's pharmacodynamic effect depends on depletion of vitamin
K-dependent clotting factors (II, VII, IX, X) with varying half-lives (6-60 hours). Factor II
(prothrombin) has the longest half-life (~60 hours), making 5-7 days necessary to
achieve steady-state anticoagulation regardless of warfarin plasma concentrations. The
patient carries CYP2C9 *1/*3 (intermediate metabolizer) and VKORC1 -1639 G/A
(intermediate sensitivity), suggesting slightly reduced warfarin requirements, but the
current INR of 1.8 on day 5 represents appropriate progression toward therapeutic
range (2.0-3.0 for AF). Option A delays appropriate monitoring; Option B risks
overshooting therapeutic range; Option D is premature given current subtherapeutic
status and would cause therapeutic delay.
Q2: A 45-year-old female with complex partial seizures is prescribed phenytoin 300 mg
daily. She has albumin 2.8 g/dL (normal 3.5-5.0). Her total phenytoin level is 12 mcg/mL
(therapeutic 10-20). What is the most accurate assessment of her pharmacokinetic
status?
A. Therapeutic; continue current dose
B. Subtherapeutic; increase dose to achieve 15-20 mcg/mL total level
C. Likely toxic; phenytoin is highly protein-bound and hypoalbuminemia increases free
fraction [CORRECT]
D. Requires immediate discontinuation due to severe toxicity
Correct Answer: C
,Rationale: Phenytoin is 90% protein-bound, primarily to albumin. In hypoalbuminemia,
the free fraction increases from ~10% to 15-20%, dramatically increasing
pharmacologic effect despite "normal" total levels. The corrected phenytoin level =
measured level / [(0.25 × albumin) + 0.1] = 12 / [(0.25 × 2.8) + 0.1] = .8 = 15
mcg/mL equivalent. However, free phenytoin levels (therapeutic 1-2 mcg/mL) would
likely exceed 2 mcg/mL, indicating neurotoxicity risk. Option A ignores protein-binding
alterations; Option B would cause definite toxicity; Option D is excessive without clinical
toxicity signs.
Q3: A 55-year-old male with HIV (CD4 200) starts efavirenz-based ART. He reports vivid
dreams and dizziness. Pharmacokinetically, which principle explains these early
adverse effects?
A. CYP3A4 inhibition causing drug accumulation
B. CNS penetration and long half-life (40-55 hours) with steady-state accumulation
[CORRECT]
C. Rapid distribution to adipose tissue causing delayed CNS effects
D. P-glycoprotein efflux preventing CNS penetration
Correct Answer: B
Rationale: Efavirenz is a lipophilic non-nucleoside reverse transcriptase inhibitor
(NNRTI) with excellent CNS penetration and long elimination half-life (40-55 hours).
, Adverse CNS effects (vivid dreams, dizziness, confusion) occur in 50% of patients
during first 2-4 weeks due to accumulation toward steady state, which requires ~5
half-lives (8-11 days). These effects typically resolve after 2-4 weeks despite continued
therapy. Option A is incorrect—efavirenz induces CYP3A4; Option C is
backwards—lipophilic drugs distribute to fat, but CNS effects occur rapidly due to high
brain penetration; Option D is incorrect—efavirenz crosses the blood-brain barrier
effectively.
Q4: For a drug following first-order kinetics with half-life of 6 hours, approximately what
percentage remains after 24 hours?
A. 6.25% [CORRECT]
B. 12.5%
C. 25%
D. 50%
Correct Answer: A
Rationale: First-order elimination: constant percentage eliminated per unit time. After n
half-lives, remaining drug = (1/2)ⁿ × 100%. Twenty-four hours = 4 half-lives (24/6).
Remaining = (1/2)⁴ × 100% = 1/16 × 100% = 6.25%. Option B represents 3 half-lives;
Option C represents 2 half-lives; Option D represents 1 half-life.
