the AGACNP 2026
SECTION 1: NEUROPHARMACOLOGY & PSYCHIATRIC
DRUGS (Questions 1–30)
Question 1: A drug that is highly lipophilic (fat-soluble) would be expected
to have which characteristic?
A) Low volume of distribution
B) High volume of distribution
C) Rapid renal elimination
D) Low protein binding
Correct Answer: B) High volume of distribution
Rationale: Lipophilic drugs have a high volume of distribution because they
readily cross cell membranes and accumulate in fatty tissues. Hydrophilic
drugs have a lower volume of distribution and remain primarily in the
vascular compartment. Volume of distribution is an important
pharmacokinetic parameter that affects drug dosing and elimination.
Question 2: A patient with hepatic impairment is prescribed a medication
that undergoes extensive first-pass metabolism. What adjustment is
needed?
A) Increase the dose
B) Decrease the dose or use an alternative route
C) No adjustment is needed
D) Increase the dosing frequency
,Correct Answer: B) Decrease the dose or use an alternative route
Rationale: Drugs that undergo extensive first-pass metabolism (e.g.,
propranolol, morphine, nitroglycerin) have reduced bioavailability when
given orally. In hepatic impairment, first-pass metabolism is reduced, leading
to increased bioavailability and risk of toxicity. Dose reduction or alternative
routes (IV, sublingual) may be needed.
Question 3: A patient with renal impairment is prescribed a medication
that is primarily renally excreted. Which pharmacokinetic parameter is most
affected?
A) Absorption
B) Distribution
C) Metabolism
D) Elimination
Correct Answer: D) Elimination
Rationale: Renal impairment primarily affects drug elimination (excretion).
Drugs that are renally cleared will accumulate, requiring dose reduction or
extended dosing intervals. Metabolism (hepatic) may be affected by liver
disease. Absorption and distribution are less directly affected by renal
function.
Question 4: A drug with a half-life of 24 hours is started. Approximately
how many days will it take to reach steady-state?
A) 2 days
B) 3 days
,C) 4 days
D) 5 days
Correct Answer: D) 5 days
Rationale: Steady-state is reached after approximately 4-5 half-lives. For a
drug with a 24-hour half-life, steady-state would be reached in
approximately 4-5 days (96-120 hours). This is important for drugs that
require therapeutic monitoring to know when to draw levels.
Question 5: A highly protein-bound drug is administered to a patient with
low serum albumin. What is the expected effect?
A) Decreased free drug concentration
B) Increased free drug concentration
C) Decreased drug effect
D) No change in drug effect
Correct Answer: B) Increased free drug concentration
Rationale: Low serum albumin (e.g., in liver disease, nephrotic syndrome,
malnutrition) reduces protein binding sites, increasing the free (active)
fraction of highly protein-bound drugs. This can lead to increased drug effect
and toxicity. Examples include warfarin, phenytoin, and valproic acid.
Question 6: Which of the following is an example of pharmacodynamic
drug interaction?
A) CYP450 enzyme induction
B) Competitive protein binding
C) Additive sedation from two CNS depressants
D) Decreased renal excretion
, Correct Answer: C) Additive sedation from two CNS depressants
Rationale: Pharmacodynamic interactions occur when drugs have additive,
synergistic, or antagonistic effects at the receptor level. Additive sedation
from combining benzodiazepines and opioids is a pharmacodynamic
interaction. CYP450 induction (A), protein binding (B), and renal excretion
changes (D) are pharmacokinetic interactions.
Question 7: A patient is started on a drug that is a CYP3A4 inducer. Which
effect would be expected on other medications metabolized by CYP3A4?
A) Increased serum levels and toxicity
B) Decreased serum levels and reduced effectiveness
C) No effect on other medications
D) Increased protein binding
*Correct Answer: B) Decreased serum levels and reduced effectiveness
Rationale: CYP450 inducers (e.g., rifampin, phenytoin, carbamazepine, St.
John's wort) increase the metabolism of other drugs that are substrates for
the same enzyme, leading to lower serum levels and reduced therapeutic
effect. This is a clinically significant drug interaction that requires monitoring.
Question 8: A patient is prescribed a medication that is a CYP3A4 inhibitor.
Which effect would be expected on other medications metabolized by
CYP3A4?
A) Decreased serum levels
B) Increased serum levels and toxicity
C) No effect on other medications
D) Decreased protein binding