Chamberlain University NR 566 Week 7 Exam (pdf) |
2026/2027 | CNS Disorders & Psychopharmacology Q&A |
Nursing
1. A patient is prescribed levodopa/carbidopa for Parkinson’s disease. The nurse practitioner
instructs the patient to avoid taking the medication with a high-protein meal. What is the primary
rationale for this instruction?
A) Protein enhances the renal clearance of levodopa
B) High-protein meals compete with levodopa for absorption in the gut
C) Protein increases the metabolism of levodopa by CYP3A4
D) High-protein meals reduce the blood-brain barrier permeability to levodopa
Correct Answer: High-protein meals compete with levodopa for absorption in the gut
Rationale: Levodopa is absorbed in the small intestine via the large neutral amino acid transporter,
the same transporter used by dietary amino acids from protein. High-protein meals can competitively
inhibit levodopa absorption, reducing its bioavailability and therapeutic effect. This is why patients
are often advised to take levodopa 30 minutes before meals or to distribute protein intake throughout
the day to minimize motor fluctuations. Other options do not accurately describe this competitive
absorption mechanism.
2. Which of the following best describes the mechanism of action of lamotrigine in the treatment
of epilepsy?
A) It enhances GABA-mediated chloride influx at GABA-A receptors
B) It inhibits voltage-gated sodium channels, stabilizing neuronal membranes and reducing glutamate
release
C) It blocks T-type calcium channels in thalamic neurons
D) It antagonizes NMDA receptors, reducing excitatory neurotransmission
Correct Answer: It inhibits voltage-gated sodium channels, stabilizing neuronal membranes and
reducing glutamate release
Rationale: Lamotrigine exerts its antiepileptic effects by inhibiting voltage-gated sodium channels in
neurons, which stabilizes nerve membranes and decreases the release of excitatory neurotransmitters
such as glutamate. This mechanism is particularly effective for partial seizures and generalized
seizures. The drug also has mood-stabilizing properties, making it useful in bipolar disorder. Options
A, C, and D describe mechanisms of other antiepileptic drugs, not lamotrigine.
,3. A researcher is studying the pharmacokinetics of donepezil in older adults with Alzheimer’s
disease. Which cytochrome P450 enzymes are primarily responsible for the metabolism of
donepezil?
A) CYP1A2 and CYP2E1
B) CYP2C9 and CYP2C19
C) CYP2D6 and CYP3A4
D) CYP2B6 and CYP2A6
Correct Answer: CYP2D6 and CYP3A4
Rationale: Donepezil is metabolized primarily by CYP2D6 and CYP3A4 enzymes in the liver. This is
clinically significant because inhibitors of these enzymes can increase donepezil levels and the risk of
adverse effects, while inducers can reduce its efficacy. Patients taking medications that affect these
pathways should be monitored for changes in cognitive function and cholinergic side effects. The
other enzyme combinations listed are not the primary metabolic pathways for donepezil.
4. In the context of antiepileptic drug therapy, which principle explains why phenytoin requires
therapeutic drug monitoring?
A) Phenytoin has a narrow therapeutic index and exhibits nonlinear pharmacokinetics
B) Phenytoin is eliminated exclusively by renal filtration without metabolism
C) Phenytoin has a very short half-life requiring frequent dosing
D) Phenytoin induces its own metabolism, leading to autoinduction
Correct Answer: Phenytoin has a narrow therapeutic index and exhibits nonlinear
pharmacokinetics
Rationale: Phenytoin has a narrow therapeutic index, meaning the difference between therapeutic
and toxic serum concentrations is small. Additionally, phenytoin exhibits nonlinear (zero-order)
pharmacokinetics at therapeutic doses because its metabolizing enzymes become saturated, leading
to disproportionate increases in serum levels with dose escalations. Therapeutic drug monitoring is
essential to maintain levels within the therapeutic range of 10–20 mcg/mL and to avoid toxicity. The
other options do not accurately describe phenytoin’s pharmacokinetic profile.
5. A 68-year-old man with Parkinson’s disease has been stable on carbidopa/levodopa for several
years. He now reports unpredictable “off” episodes where his mobility suddenly deteriorates.
Which class of medication is most commonly added to manage these motor fluctuations?
A) Selective serotonin reuptake inhibitors
B) COMT inhibitors such as entacapone
C) Benzodiazepines such as lorazepam
D) Anticholinergic agents such as benztropine
,Correct Answer: COMT inhibitors such as entacapone
Rationale: COMT inhibitors such as entacapone and tolcapone are commonly added to
carbidopa/levodopa therapy to manage motor fluctuations and “off” episodes. By inhibiting catechol-
O-methyltransferase, these agents extend the half-life of levodopa and increase its bioavailability,
providing more sustained dopaminergic stimulation. SSRIs, benzodiazepines, and anticholinergics do
not address the underlying dopaminergic deficit that causes motor fluctuations. This combination
therapy is a standard approach for patients experiencing wearing-off phenomena.
6. Which factor is most important when determining the appropriate dose of gabapentin in a
patient with chronic kidney disease?
A) Serum albumin levels
B) Creatinine clearance
C) Hepatic transaminase levels
D) Body mass index
Correct Answer: Creatinine clearance
Rationale: Gabapentin is eliminated unchanged by the kidneys, so renal function is the primary
determinant of dosing. Creatinine clearance is used to calculate the appropriate dose and dosing
interval to prevent drug accumulation and toxicity, which can manifest as sedation, dizziness, and
ataxia. Unlike many other medications, gabapentin is not hepatically metabolized, so liver function
tests are not relevant for dosing. Serum albumin and body mass index do not significantly affect
gabapentin pharmacokinetics.
7. What is the primary function of the blood-brain barrier in the context of central nervous system
pharmacology?
A) It actively transports all drugs into the brain to enhance therapeutic effects
B) It impedes the entry of many drugs into the brain, limiting treatment options for CNS disorders
C) It metabolizes drugs before they can reach brain tissue
D) It increases the permeability of lipid-insoluble drugs into the CNS
Correct Answer: It impedes the entry of many drugs into the brain, limiting treatment options for
CNS disorders
Rationale: The blood-brain barrier is a highly selective semipermeable membrane that restricts the
entry of many substances, including most drugs, from the bloodstream into the brain. Only lipid-
soluble agents and drugs that cross via specific transport systems can penetrate this barrier. This
barrier presents a significant challenge in treating CNS disorders because many potentially effective
drugs cannot reach therapeutic concentrations in brain tissue. The other options do not accurately
describe the function of the blood-brain barrier.
, 8. According to current guidelines, which cholinesterase inhibitor is also approved for the
treatment of moderate to severe Alzheimer’s disease at a higher dose of 23 mg/day?
A) Rivastigmine
B) Galantamine
C) Donepezil
D) Memantine
Correct Answer: Donepezil
Rationale: Donepezil is approved for mild, moderate, and severe Alzheimer’s disease, and a 23
mg/day formulation is available for moderate to severe stages. The higher dose provides minimal
additional cognitive benefit compared to 10 mg/day but is associated with a higher incidence of
adverse effects, particularly gastrointestinal symptoms. Rivastigmine and galantamine do not have
an approved 23 mg/day formulation. Memantine is an NMDA receptor antagonist, not a
cholinesterase inhibitor.
9. A patient with epilepsy is prescribed ethosuximide. Which seizure type is this medication most
effective in treating?
A) Tonic-clonic seizures
B) Complex partial seizures
C) Absence seizures
D) Myoclonic seizures
Correct Answer: Absence seizures
Rationale: Ethosuximide is the drug of choice for absence seizures (formerly called petit mal seizures).
Its mechanism involves blocking T-type calcium channels in thalamic neurons, which are involved in
the generation of absence seizure activity. Ethosuximide is not effective for tonic-clonic, partial, or
myoclonic seizures. For patients with both absence and tonic-clonic seizures, valproic acid is often
preferred because it covers both seizure types.
10. Which statement best explains why rivastigmine is available as a transdermal patch?
A) The patch provides more rapid absorption than oral administration
B) The patch bypasses hepatic first-pass metabolism and reduces gastrointestinal side effects
C) The patch allows for once-weekly dosing to improve adherence
D) The patch delivers the drug directly to the brain via the bloodstream
Correct Answer: The patch bypasses hepatic first-pass metabolism and reduces gastrointestinal
side effects
Rationale: The rivastigmine transdermal patch offers several advantages over oral formulations,
including bypassing hepatic first-pass metabolism and providing more consistent plasma levels. Most
2026/2027 | CNS Disorders & Psychopharmacology Q&A |
Nursing
1. A patient is prescribed levodopa/carbidopa for Parkinson’s disease. The nurse practitioner
instructs the patient to avoid taking the medication with a high-protein meal. What is the primary
rationale for this instruction?
A) Protein enhances the renal clearance of levodopa
B) High-protein meals compete with levodopa for absorption in the gut
C) Protein increases the metabolism of levodopa by CYP3A4
D) High-protein meals reduce the blood-brain barrier permeability to levodopa
Correct Answer: High-protein meals compete with levodopa for absorption in the gut
Rationale: Levodopa is absorbed in the small intestine via the large neutral amino acid transporter,
the same transporter used by dietary amino acids from protein. High-protein meals can competitively
inhibit levodopa absorption, reducing its bioavailability and therapeutic effect. This is why patients
are often advised to take levodopa 30 minutes before meals or to distribute protein intake throughout
the day to minimize motor fluctuations. Other options do not accurately describe this competitive
absorption mechanism.
2. Which of the following best describes the mechanism of action of lamotrigine in the treatment
of epilepsy?
A) It enhances GABA-mediated chloride influx at GABA-A receptors
B) It inhibits voltage-gated sodium channels, stabilizing neuronal membranes and reducing glutamate
release
C) It blocks T-type calcium channels in thalamic neurons
D) It antagonizes NMDA receptors, reducing excitatory neurotransmission
Correct Answer: It inhibits voltage-gated sodium channels, stabilizing neuronal membranes and
reducing glutamate release
Rationale: Lamotrigine exerts its antiepileptic effects by inhibiting voltage-gated sodium channels in
neurons, which stabilizes nerve membranes and decreases the release of excitatory neurotransmitters
such as glutamate. This mechanism is particularly effective for partial seizures and generalized
seizures. The drug also has mood-stabilizing properties, making it useful in bipolar disorder. Options
A, C, and D describe mechanisms of other antiepileptic drugs, not lamotrigine.
,3. A researcher is studying the pharmacokinetics of donepezil in older adults with Alzheimer’s
disease. Which cytochrome P450 enzymes are primarily responsible for the metabolism of
donepezil?
A) CYP1A2 and CYP2E1
B) CYP2C9 and CYP2C19
C) CYP2D6 and CYP3A4
D) CYP2B6 and CYP2A6
Correct Answer: CYP2D6 and CYP3A4
Rationale: Donepezil is metabolized primarily by CYP2D6 and CYP3A4 enzymes in the liver. This is
clinically significant because inhibitors of these enzymes can increase donepezil levels and the risk of
adverse effects, while inducers can reduce its efficacy. Patients taking medications that affect these
pathways should be monitored for changes in cognitive function and cholinergic side effects. The
other enzyme combinations listed are not the primary metabolic pathways for donepezil.
4. In the context of antiepileptic drug therapy, which principle explains why phenytoin requires
therapeutic drug monitoring?
A) Phenytoin has a narrow therapeutic index and exhibits nonlinear pharmacokinetics
B) Phenytoin is eliminated exclusively by renal filtration without metabolism
C) Phenytoin has a very short half-life requiring frequent dosing
D) Phenytoin induces its own metabolism, leading to autoinduction
Correct Answer: Phenytoin has a narrow therapeutic index and exhibits nonlinear
pharmacokinetics
Rationale: Phenytoin has a narrow therapeutic index, meaning the difference between therapeutic
and toxic serum concentrations is small. Additionally, phenytoin exhibits nonlinear (zero-order)
pharmacokinetics at therapeutic doses because its metabolizing enzymes become saturated, leading
to disproportionate increases in serum levels with dose escalations. Therapeutic drug monitoring is
essential to maintain levels within the therapeutic range of 10–20 mcg/mL and to avoid toxicity. The
other options do not accurately describe phenytoin’s pharmacokinetic profile.
5. A 68-year-old man with Parkinson’s disease has been stable on carbidopa/levodopa for several
years. He now reports unpredictable “off” episodes where his mobility suddenly deteriorates.
Which class of medication is most commonly added to manage these motor fluctuations?
A) Selective serotonin reuptake inhibitors
B) COMT inhibitors such as entacapone
C) Benzodiazepines such as lorazepam
D) Anticholinergic agents such as benztropine
,Correct Answer: COMT inhibitors such as entacapone
Rationale: COMT inhibitors such as entacapone and tolcapone are commonly added to
carbidopa/levodopa therapy to manage motor fluctuations and “off” episodes. By inhibiting catechol-
O-methyltransferase, these agents extend the half-life of levodopa and increase its bioavailability,
providing more sustained dopaminergic stimulation. SSRIs, benzodiazepines, and anticholinergics do
not address the underlying dopaminergic deficit that causes motor fluctuations. This combination
therapy is a standard approach for patients experiencing wearing-off phenomena.
6. Which factor is most important when determining the appropriate dose of gabapentin in a
patient with chronic kidney disease?
A) Serum albumin levels
B) Creatinine clearance
C) Hepatic transaminase levels
D) Body mass index
Correct Answer: Creatinine clearance
Rationale: Gabapentin is eliminated unchanged by the kidneys, so renal function is the primary
determinant of dosing. Creatinine clearance is used to calculate the appropriate dose and dosing
interval to prevent drug accumulation and toxicity, which can manifest as sedation, dizziness, and
ataxia. Unlike many other medications, gabapentin is not hepatically metabolized, so liver function
tests are not relevant for dosing. Serum albumin and body mass index do not significantly affect
gabapentin pharmacokinetics.
7. What is the primary function of the blood-brain barrier in the context of central nervous system
pharmacology?
A) It actively transports all drugs into the brain to enhance therapeutic effects
B) It impedes the entry of many drugs into the brain, limiting treatment options for CNS disorders
C) It metabolizes drugs before they can reach brain tissue
D) It increases the permeability of lipid-insoluble drugs into the CNS
Correct Answer: It impedes the entry of many drugs into the brain, limiting treatment options for
CNS disorders
Rationale: The blood-brain barrier is a highly selective semipermeable membrane that restricts the
entry of many substances, including most drugs, from the bloodstream into the brain. Only lipid-
soluble agents and drugs that cross via specific transport systems can penetrate this barrier. This
barrier presents a significant challenge in treating CNS disorders because many potentially effective
drugs cannot reach therapeutic concentrations in brain tissue. The other options do not accurately
describe the function of the blood-brain barrier.
, 8. According to current guidelines, which cholinesterase inhibitor is also approved for the
treatment of moderate to severe Alzheimer’s disease at a higher dose of 23 mg/day?
A) Rivastigmine
B) Galantamine
C) Donepezil
D) Memantine
Correct Answer: Donepezil
Rationale: Donepezil is approved for mild, moderate, and severe Alzheimer’s disease, and a 23
mg/day formulation is available for moderate to severe stages. The higher dose provides minimal
additional cognitive benefit compared to 10 mg/day but is associated with a higher incidence of
adverse effects, particularly gastrointestinal symptoms. Rivastigmine and galantamine do not have
an approved 23 mg/day formulation. Memantine is an NMDA receptor antagonist, not a
cholinesterase inhibitor.
9. A patient with epilepsy is prescribed ethosuximide. Which seizure type is this medication most
effective in treating?
A) Tonic-clonic seizures
B) Complex partial seizures
C) Absence seizures
D) Myoclonic seizures
Correct Answer: Absence seizures
Rationale: Ethosuximide is the drug of choice for absence seizures (formerly called petit mal seizures).
Its mechanism involves blocking T-type calcium channels in thalamic neurons, which are involved in
the generation of absence seizure activity. Ethosuximide is not effective for tonic-clonic, partial, or
myoclonic seizures. For patients with both absence and tonic-clonic seizures, valproic acid is often
preferred because it covers both seizure types.
10. Which statement best explains why rivastigmine is available as a transdermal patch?
A) The patch provides more rapid absorption than oral administration
B) The patch bypasses hepatic first-pass metabolism and reduces gastrointestinal side effects
C) The patch allows for once-weekly dosing to improve adherence
D) The patch delivers the drug directly to the brain via the bloodstream
Correct Answer: The patch bypasses hepatic first-pass metabolism and reduces gastrointestinal
side effects
Rationale: The rivastigmine transdermal patch offers several advantages over oral formulations,
including bypassing hepatic first-pass metabolism and providing more consistent plasma levels. Most
