NU 643 Exam 1 V3 | NU 643 Advanced
Psychopharmacology | Actual Q&A with Rationale
(NU643 Exam 1) | Regis University
1. A patient is prescribed a new medication that acts as a potent inhibitor of the CYP2D6
enzyme. Which of the following consequences is most likely if the patient is also taking a
substrate of this enzyme?
A. Increased risk of toxicity from the substrate medication
B. Decreased plasma levels of the substrate medication
C. Rapid induction of hepatic enzymes leading to tolerance
D. Increased renal clearance of the substrate medication
Correct Answer: A
Explanation: Inhibition of a CYP450 enzyme like 2D6 results in reduced metabolism of its
substrate drugs. This leads to higher plasma concentrations of the substrate, significantly
increasing the risk of adverse effects or toxicity. Clinicians must adjust doses downward or
choose alternative medications to avoid dangerous drug-drug interactions in these
patients.
2. When initiating Lithium therapy, which lab value is most critical to monitor due to the
drug’s primary route of excretion?
A. Hemoglobin A1c
B. Alanine Aminotransferase (ALT)
,C. Serum Creatinine
D. Platelet count
Correct Answer: C
Explanation: Lithium is almost exclusively excreted by the kidneys, making renal function
the primary concern for safety. An elevated serum creatinine level indicates impaired renal
clearance, which can quickly lead to toxic lithium levels in the bloodstream. Regular
monitoring of BUN and creatinine is standard practice to prevent permanent renal damage
or acute toxicity.
3. A patient diagnosed with schizophrenia experiences a reduction in positive symptoms but
begins to show signs of stiff muscles and a ‘mask-like’ face. Which dopamine pathway is being
affected by the medication to cause these side effects?
A. Mesolimbic pathway
B. Mesocortical pathway
C. Nigrostriatal pathway
D. Tuberoinfundibular pathway
Correct Answer: C
Explanation: The nigrostriatal dopamine pathway controls motor function and movement.
Blockade of D2 receptors in this specific pathway leads to extrapyramidal symptoms (EPS),
including parkinsonism, dystonia, and akathisia. While mesolimbic blockade reduces
,hallucinations, the collateral effect on the nigrostriatal tract produces the observed motor
stiffness.
4. Which of the following antidepressants is known for having an exceptionally long half-life,
meaning it does not require a slow taper when discontinued?
A. Paroxetine
B. Fluoxetine
C. Venlafaxine
D. Sertraline
Correct Answer: B
Explanation: Fluoxetine and its active metabolite norfluoxetine have a combined half-life
of one to two weeks. This long duration of action provides a ‘self-tapering’ effect as the
drug levels slowly decline in the body after the last dose. Consequently, patients are at a
much lower risk for SSRI discontinuation syndrome compared to short-acting agents like
paroxetine.
5. A patient with bipolar disorder is started on Lamotrigine. What is the most important
clinical instruction to provide regarding the titration schedule?
A. Double the dose if a mood episode occurs
B. Stop the medication immediately if you feel drowsy
C. Take the medication only when feeling manic
, D. The dose must be titrated slowly to minimize the risk of Stevens-Johnson Syndrome
Correct Answer: D
Explanation: Lamotrigine carries a black box warning for serious dermatological
reactions, including Stevens-Johnson Syndrome (SJS). A slow, standardized titration
schedule is essential to reduce the incidence of this life-threatening rash. Patients must be
educated to seek immediate medical attention if any new rash or skin peeling develops
during the first few months of treatment.
6. Which neurotransmitter is primarily involved in the mechanism of action of
benzodiazepines?
A. Glutamate
B. Norepinephrine
C. Dopamine
D. GABA
Correct Answer: D
Explanation: Benzodiazepines act as positive allosteric modulators at the GABA-A
receptor complex. By enhancing the inhibitory effects of Gamma-aminobutyric acid
(GABA), they increase chloride ion influx, leading to hyperpolarization of the neuron. This
mechanism results in the characteristic anxiolytic, sedative, and anticonvulsant effects
associated with this class of drugs.
Psychopharmacology | Actual Q&A with Rationale
(NU643 Exam 1) | Regis University
1. A patient is prescribed a new medication that acts as a potent inhibitor of the CYP2D6
enzyme. Which of the following consequences is most likely if the patient is also taking a
substrate of this enzyme?
A. Increased risk of toxicity from the substrate medication
B. Decreased plasma levels of the substrate medication
C. Rapid induction of hepatic enzymes leading to tolerance
D. Increased renal clearance of the substrate medication
Correct Answer: A
Explanation: Inhibition of a CYP450 enzyme like 2D6 results in reduced metabolism of its
substrate drugs. This leads to higher plasma concentrations of the substrate, significantly
increasing the risk of adverse effects or toxicity. Clinicians must adjust doses downward or
choose alternative medications to avoid dangerous drug-drug interactions in these
patients.
2. When initiating Lithium therapy, which lab value is most critical to monitor due to the
drug’s primary route of excretion?
A. Hemoglobin A1c
B. Alanine Aminotransferase (ALT)
,C. Serum Creatinine
D. Platelet count
Correct Answer: C
Explanation: Lithium is almost exclusively excreted by the kidneys, making renal function
the primary concern for safety. An elevated serum creatinine level indicates impaired renal
clearance, which can quickly lead to toxic lithium levels in the bloodstream. Regular
monitoring of BUN and creatinine is standard practice to prevent permanent renal damage
or acute toxicity.
3. A patient diagnosed with schizophrenia experiences a reduction in positive symptoms but
begins to show signs of stiff muscles and a ‘mask-like’ face. Which dopamine pathway is being
affected by the medication to cause these side effects?
A. Mesolimbic pathway
B. Mesocortical pathway
C. Nigrostriatal pathway
D. Tuberoinfundibular pathway
Correct Answer: C
Explanation: The nigrostriatal dopamine pathway controls motor function and movement.
Blockade of D2 receptors in this specific pathway leads to extrapyramidal symptoms (EPS),
including parkinsonism, dystonia, and akathisia. While mesolimbic blockade reduces
,hallucinations, the collateral effect on the nigrostriatal tract produces the observed motor
stiffness.
4. Which of the following antidepressants is known for having an exceptionally long half-life,
meaning it does not require a slow taper when discontinued?
A. Paroxetine
B. Fluoxetine
C. Venlafaxine
D. Sertraline
Correct Answer: B
Explanation: Fluoxetine and its active metabolite norfluoxetine have a combined half-life
of one to two weeks. This long duration of action provides a ‘self-tapering’ effect as the
drug levels slowly decline in the body after the last dose. Consequently, patients are at a
much lower risk for SSRI discontinuation syndrome compared to short-acting agents like
paroxetine.
5. A patient with bipolar disorder is started on Lamotrigine. What is the most important
clinical instruction to provide regarding the titration schedule?
A. Double the dose if a mood episode occurs
B. Stop the medication immediately if you feel drowsy
C. Take the medication only when feeling manic
, D. The dose must be titrated slowly to minimize the risk of Stevens-Johnson Syndrome
Correct Answer: D
Explanation: Lamotrigine carries a black box warning for serious dermatological
reactions, including Stevens-Johnson Syndrome (SJS). A slow, standardized titration
schedule is essential to reduce the incidence of this life-threatening rash. Patients must be
educated to seek immediate medical attention if any new rash or skin peeling develops
during the first few months of treatment.
6. Which neurotransmitter is primarily involved in the mechanism of action of
benzodiazepines?
A. Glutamate
B. Norepinephrine
C. Dopamine
D. GABA
Correct Answer: D
Explanation: Benzodiazepines act as positive allosteric modulators at the GABA-A
receptor complex. By enhancing the inhibitory effects of Gamma-aminobutyric acid
(GABA), they increase chloride ion influx, leading to hyperpolarization of the neuron. This
mechanism results in the characteristic anxiolytic, sedative, and anticonvulsant effects
associated with this class of drugs.
