NR 546 ADVANCED PHARMACOLOGY COMPREHENSIVE
MIDTERM EXAM 2026/2027 | Tested Questions with Revised
Answers | Across the Lifespan | Pass Guaranteed - A+
Graded
SECTION 1: NEUROBIOLOGY AND
PHARMACOKINETICS/PHARMACODYNAMICS (Questions 1-20)
Q1: Which neurotransmitter is synthesized from the amino acid tryptophan through the
intermediate 5-hydroxytryptophan (5-HTP)?
A. Dopamine
B. Norepinephrine
C. Serotonin [CORRECT]
D. Gamma-aminobutyric acid (GABA)
Correct Answer: C
Rationale: Serotonin (5-HT) synthesis: Tryptophan → 5-HTP (via tryptophan hydroxylase,
rate-limiting step) → Serotonin (via aromatic L-amino acid decarboxylase). This
pathway is distinct from catecholamine synthesis (tyrosine → L-DOPA → dopamine →
norepinephrine → epinephrine). Option A (dopamine) and B (norepinephrine) derive
from tyrosine. Option D (GABA) derives from glutamate via glutamic acid
decarboxylase. Clinical relevance: Tryptophan depletion can precipitate depression;
5-HTP supplements may interact with serotonergic drugs.
Q2: The D2 receptor subtype is primarily located postsynaptically and mediates which
effect when stimulated?
,A. Inhibition of adenylyl cyclase and decreased cAMP [CORRECT]
B. Activation of adenylyl cyclase and increased cAMP
C. Opening of ligand-gated sodium channels
D. Closure of voltage-gated calcium channels
Correct Answer: A
Rationale: D2 receptors are Gαi/o-coupled metabotropic receptors. Stimulation inhibits
adenylyl cyclase, decreases cAMP, and inhibits protein kinase A (PKA). This
hyperpolarizes neurons (opens potassium channels, closes calcium channels). Clinical
relevance: D2 blockade (antipsychotics) disinhibits cAMP pathways. Option B describes
D1/D5 receptors (Gαs-coupled, excitatory). Option C describes ionotropic receptors
(nicotinic, AMPA). Option D describes indirect effect, not primary transduction.
Q3: Which CYP450 isoenzyme is responsible for metabolizing approximately 50% of all
psychotropic medications?
A. CYP1A2
B. CYP2C9
C. CYP2D6
D. CYP3A4 [CORRECT]
Correct Answer: D
Rationale: CYP3A4 metabolizes ~50% of all drugs, including most benzodiazepines,
atypical antipsychotics (quetiapine, lurasidone, ziprasidone), some SSRIs (sertraline,
citalopram), and buspirone. It is highly inducible and inhibited. CYP2D6 (C) is second
most important for psychotropics (~25% of drugs, including many antidepressants,
antipsychotics, and codeine). Clinical relevance: CYP3A4 inhibitors (ketoconazole,
grapefruit juice, ritonavir) dramatically increase levels of substrates; inducers
(carbamazepine, rifampin, St. John's Wort) decrease levels.
,Q4: A 72-year-old patient has decreased hepatic blood flow and reduced CYP450
activity. Which pharmacokinetic parameter is most significantly affected?
A. Absorption
B. Distribution
C. First-pass metabolism and clearance [CORRECT]
D. Bioavailability of sublingual medications
Correct Answer: C
Rationale: Aging effects on pharmacokinetics: Hepatic blood flow decreases 40-50% by
age 90; CYP450 activity declines 20-40%; Phase II metabolism (glucuronidation)
relatively preserved. Result: Decreased first-pass metabolism, increased bioavailability
of high-extraction drugs, prolonged half-life, reduced clearance, and increased drug
accumulation. Geriatric prescribing: Start low, go slow; consider 25-50% dose
reductions; extend dosing intervals. Options A, B, and D are less affected by hepatic
changes (absorption may decrease slightly due to gut changes; distribution changes
due to body composition).
Q5: Which term describes the time required for drug concentration to reach 90% of
steady-state with repeated dosing?
A. One half-life
B. Three half-lives
C. Four half-lives [CORRECT]
D. Seven half-lives
Correct Answer: C
Rationale: Steady-state kinetics: After each half-life, 50% of remaining distance to
steady-state is eliminated. 1 half-life: 50% of steady-state; 2 half-lives: 75%; 3 half-lives:
, 87.5%; 4 half-lives: 93.75% (~90%); 5 half-lives: 96.875%. Clinical relevance: Therapeutic
drug monitoring (lithium, valproate, carbamazepine) should occur after 4-5 half-lives at
constant dose. Loading doses can achieve therapeutic levels immediately (e.g.,
valproate in acute mania). Option A is too early; B is close but insufficient; D is beyond
90% (used for drug elimination: 7 half-lives = ~99% elimination).
Q6: P-glycoprotein (P-gp) in the blood-brain barrier serves which function?
A. Facilitates drug entry into the CNS
B. Actively transports drugs out of the CNS [CORRECT]
C. Metabolizes lipophilic drugs to hydrophilic metabolites
D. Synthesizes neurotransmitters from circulating precursors
Correct Answer: B
Rationale: P-glycoprotein (ABCB1) is an ATP-dependent efflux transporter on endothelial
cells of the blood-brain barrier. It limits CNS penetration of many drugs by actively
pumping them back into circulation. Substrates: Many antipsychotics, antidepressants,
opioids, chemotherapeutics. Inhibitors: Quetiapine, fluvoxamine, ritonavir (increase CNS
penetration of other drugs). Clinical relevance: P-gp polymorphisms affect drug
response and side effects; P-gp inhibition can increase CNS toxicity (loperamide + P-gp
inhibitor = respiratory depression).
Q7: Which receptor antagonism is primarily responsible for the metabolic side effects
(weight gain, dyslipidemia) of second-generation antipsychotics?
A. D2 receptor blockade
B. 5-HT2A receptor blockade
C. 5-HT2C receptor blockade [CORRECT]
D. Alpha-1 adrenergic receptor blockade
MIDTERM EXAM 2026/2027 | Tested Questions with Revised
Answers | Across the Lifespan | Pass Guaranteed - A+
Graded
SECTION 1: NEUROBIOLOGY AND
PHARMACOKINETICS/PHARMACODYNAMICS (Questions 1-20)
Q1: Which neurotransmitter is synthesized from the amino acid tryptophan through the
intermediate 5-hydroxytryptophan (5-HTP)?
A. Dopamine
B. Norepinephrine
C. Serotonin [CORRECT]
D. Gamma-aminobutyric acid (GABA)
Correct Answer: C
Rationale: Serotonin (5-HT) synthesis: Tryptophan → 5-HTP (via tryptophan hydroxylase,
rate-limiting step) → Serotonin (via aromatic L-amino acid decarboxylase). This
pathway is distinct from catecholamine synthesis (tyrosine → L-DOPA → dopamine →
norepinephrine → epinephrine). Option A (dopamine) and B (norepinephrine) derive
from tyrosine. Option D (GABA) derives from glutamate via glutamic acid
decarboxylase. Clinical relevance: Tryptophan depletion can precipitate depression;
5-HTP supplements may interact with serotonergic drugs.
Q2: The D2 receptor subtype is primarily located postsynaptically and mediates which
effect when stimulated?
,A. Inhibition of adenylyl cyclase and decreased cAMP [CORRECT]
B. Activation of adenylyl cyclase and increased cAMP
C. Opening of ligand-gated sodium channels
D. Closure of voltage-gated calcium channels
Correct Answer: A
Rationale: D2 receptors are Gαi/o-coupled metabotropic receptors. Stimulation inhibits
adenylyl cyclase, decreases cAMP, and inhibits protein kinase A (PKA). This
hyperpolarizes neurons (opens potassium channels, closes calcium channels). Clinical
relevance: D2 blockade (antipsychotics) disinhibits cAMP pathways. Option B describes
D1/D5 receptors (Gαs-coupled, excitatory). Option C describes ionotropic receptors
(nicotinic, AMPA). Option D describes indirect effect, not primary transduction.
Q3: Which CYP450 isoenzyme is responsible for metabolizing approximately 50% of all
psychotropic medications?
A. CYP1A2
B. CYP2C9
C. CYP2D6
D. CYP3A4 [CORRECT]
Correct Answer: D
Rationale: CYP3A4 metabolizes ~50% of all drugs, including most benzodiazepines,
atypical antipsychotics (quetiapine, lurasidone, ziprasidone), some SSRIs (sertraline,
citalopram), and buspirone. It is highly inducible and inhibited. CYP2D6 (C) is second
most important for psychotropics (~25% of drugs, including many antidepressants,
antipsychotics, and codeine). Clinical relevance: CYP3A4 inhibitors (ketoconazole,
grapefruit juice, ritonavir) dramatically increase levels of substrates; inducers
(carbamazepine, rifampin, St. John's Wort) decrease levels.
,Q4: A 72-year-old patient has decreased hepatic blood flow and reduced CYP450
activity. Which pharmacokinetic parameter is most significantly affected?
A. Absorption
B. Distribution
C. First-pass metabolism and clearance [CORRECT]
D. Bioavailability of sublingual medications
Correct Answer: C
Rationale: Aging effects on pharmacokinetics: Hepatic blood flow decreases 40-50% by
age 90; CYP450 activity declines 20-40%; Phase II metabolism (glucuronidation)
relatively preserved. Result: Decreased first-pass metabolism, increased bioavailability
of high-extraction drugs, prolonged half-life, reduced clearance, and increased drug
accumulation. Geriatric prescribing: Start low, go slow; consider 25-50% dose
reductions; extend dosing intervals. Options A, B, and D are less affected by hepatic
changes (absorption may decrease slightly due to gut changes; distribution changes
due to body composition).
Q5: Which term describes the time required for drug concentration to reach 90% of
steady-state with repeated dosing?
A. One half-life
B. Three half-lives
C. Four half-lives [CORRECT]
D. Seven half-lives
Correct Answer: C
Rationale: Steady-state kinetics: After each half-life, 50% of remaining distance to
steady-state is eliminated. 1 half-life: 50% of steady-state; 2 half-lives: 75%; 3 half-lives:
, 87.5%; 4 half-lives: 93.75% (~90%); 5 half-lives: 96.875%. Clinical relevance: Therapeutic
drug monitoring (lithium, valproate, carbamazepine) should occur after 4-5 half-lives at
constant dose. Loading doses can achieve therapeutic levels immediately (e.g.,
valproate in acute mania). Option A is too early; B is close but insufficient; D is beyond
90% (used for drug elimination: 7 half-lives = ~99% elimination).
Q6: P-glycoprotein (P-gp) in the blood-brain barrier serves which function?
A. Facilitates drug entry into the CNS
B. Actively transports drugs out of the CNS [CORRECT]
C. Metabolizes lipophilic drugs to hydrophilic metabolites
D. Synthesizes neurotransmitters from circulating precursors
Correct Answer: B
Rationale: P-glycoprotein (ABCB1) is an ATP-dependent efflux transporter on endothelial
cells of the blood-brain barrier. It limits CNS penetration of many drugs by actively
pumping them back into circulation. Substrates: Many antipsychotics, antidepressants,
opioids, chemotherapeutics. Inhibitors: Quetiapine, fluvoxamine, ritonavir (increase CNS
penetration of other drugs). Clinical relevance: P-gp polymorphisms affect drug
response and side effects; P-gp inhibition can increase CNS toxicity (loperamide + P-gp
inhibitor = respiratory depression).
Q7: Which receptor antagonism is primarily responsible for the metabolic side effects
(weight gain, dyslipidemia) of second-generation antipsychotics?
A. D2 receptor blockade
B. 5-HT2A receptor blockade
C. 5-HT2C receptor blockade [CORRECT]
D. Alpha-1 adrenergic receptor blockade
