, Question 1
A patient with a history of opioid use disorder is prescribed
buprenorphine/naloxone. Which pharmacologic property best explains its
ceiling effect on respiratory depression?
A. High intrinsic activity at the mu-opioid receptor
B. Partial agonism at the mu-opioid receptor
C. Competitive antagonism at the kappa-opioid receptor
D. Irreversible inhibition of CYP3A4
Correct Answer: B - Partial agonism at the mu-opioid receptor
RATIONALE
Buprenorphine is a partial mu-opioid agonist, which produces
submaximal receptor activation and a ceiling effect on respiratory
depression. Full agonists like methadone (A) lack this ceiling. Kappa
antagonism (C) contributes to antidepressant effects but not
respiratory ceiling. CYP3A4 inhibition (D) affects metabolism, not
receptor-mediated respiratory depression.
Question 2
Which DEA schedule is assigned to a drug with high abuse potential, no
accepted medical use, and lack of safety even under medical supervision?
A. Schedule I
B. Schedule II
C. Schedule III
D. Schedule IV
Correct Answer: A - Schedule I
Page 2
, RATIONALE
Schedule I drugs have no currently accepted medical use and a high
potential for abuse (e.g., heroin, LSD). Schedule II (B) drugs have
accepted medical use but severe abuse potential. Schedules III (C) and
IV (D) have progressively lower abuse potential and accepted medical
uses.
Question 3
A patient taking fluoxetine reports inadequate relief from tramadol for pain.
Which interaction is most likely responsible for reduced analgesia?
A. Fluoxetine inhibits CYP2D6, reducing tramadol conversion to its
active metabolite
B. Fluoxetine induces CYP3A4, increasing tramadol clearance
C. Tramadol inhibits serotonin reuptake, causing serotonin syndrome
D. Fluoxetine competes for renal tubular secretion of tramadol
Correct Answer: A - Fluoxetine inhibits CYP2D6, reducing
tramadol conversion to its active metabolite
RATIONALE
Tramadol requires CYP2D6-mediated metabolism to
O-desmethyltramadol for analgesic efficacy. Fluoxetine is a strong
CYP2D6 inhibitor, reducing this conversion. CYP3A4 induction (B) is
not a primary fluoxetine effect. Serotonin syndrome (C) is a risk but
does not explain reduced analgesia. Renal competition (D) is not a
major mechanism.
Question 4
Which statement best reflects the role of pharmacogenomic testing for
CYP2D6 in codeine prescribing?
A. Ultra-rapid metabolizers may experience life-threatening toxicity from
standard doses
B. Poor metabolizers require higher doses to achieve analgesia
Page 3
, C. CYP2D6 genotype does not affect codeine efficacy
D. Testing is mandatory before any opioid prescription
Correct Answer: A - Ultra-rapid metabolizers may experience
life-threatening toxicity from standard doses
RATIONALE
Ultra-rapid CYP2D6 metabolizers convert codeine to morphine
rapidly, risking respiratory depression. Poor metabolizers (B) may get
little analgesia due to reduced conversion. Genotype significantly
affects efficacy (C). Testing is recommended but not mandatory (D).
Question 5
A patient on long-term opioid therapy for chronic pain develops myoclonus
and hyperalgesia. Which opioid is most likely responsible due to accumulation
of neuroexcitatory metabolites?
A. Morphine
B. Fentanyl
C. Methadone
D. Oxycodone
Correct Answer: A - Morphine
RATIONALE
Morphine-6-glucuronide and morphine-3-glucuronide can accumulate
in renal impairment, causing myoclonus and hyperalgesia. Fentanyl
(B) has no active metabolites. Methadone (C) can cause QT
prolongation but not typically myoclonus from metabolites.
Oxycodone (D) metabolites are less neuroexcitatory.
Question 6
Which antidepressant is most appropriate for a patient with chronic pain and
insomnia, given its dual mechanism?
A. Fluoxetine
Page 4
A patient with a history of opioid use disorder is prescribed
buprenorphine/naloxone. Which pharmacologic property best explains its
ceiling effect on respiratory depression?
A. High intrinsic activity at the mu-opioid receptor
B. Partial agonism at the mu-opioid receptor
C. Competitive antagonism at the kappa-opioid receptor
D. Irreversible inhibition of CYP3A4
Correct Answer: B - Partial agonism at the mu-opioid receptor
RATIONALE
Buprenorphine is a partial mu-opioid agonist, which produces
submaximal receptor activation and a ceiling effect on respiratory
depression. Full agonists like methadone (A) lack this ceiling. Kappa
antagonism (C) contributes to antidepressant effects but not
respiratory ceiling. CYP3A4 inhibition (D) affects metabolism, not
receptor-mediated respiratory depression.
Question 2
Which DEA schedule is assigned to a drug with high abuse potential, no
accepted medical use, and lack of safety even under medical supervision?
A. Schedule I
B. Schedule II
C. Schedule III
D. Schedule IV
Correct Answer: A - Schedule I
Page 2
, RATIONALE
Schedule I drugs have no currently accepted medical use and a high
potential for abuse (e.g., heroin, LSD). Schedule II (B) drugs have
accepted medical use but severe abuse potential. Schedules III (C) and
IV (D) have progressively lower abuse potential and accepted medical
uses.
Question 3
A patient taking fluoxetine reports inadequate relief from tramadol for pain.
Which interaction is most likely responsible for reduced analgesia?
A. Fluoxetine inhibits CYP2D6, reducing tramadol conversion to its
active metabolite
B. Fluoxetine induces CYP3A4, increasing tramadol clearance
C. Tramadol inhibits serotonin reuptake, causing serotonin syndrome
D. Fluoxetine competes for renal tubular secretion of tramadol
Correct Answer: A - Fluoxetine inhibits CYP2D6, reducing
tramadol conversion to its active metabolite
RATIONALE
Tramadol requires CYP2D6-mediated metabolism to
O-desmethyltramadol for analgesic efficacy. Fluoxetine is a strong
CYP2D6 inhibitor, reducing this conversion. CYP3A4 induction (B) is
not a primary fluoxetine effect. Serotonin syndrome (C) is a risk but
does not explain reduced analgesia. Renal competition (D) is not a
major mechanism.
Question 4
Which statement best reflects the role of pharmacogenomic testing for
CYP2D6 in codeine prescribing?
A. Ultra-rapid metabolizers may experience life-threatening toxicity from
standard doses
B. Poor metabolizers require higher doses to achieve analgesia
Page 3
, C. CYP2D6 genotype does not affect codeine efficacy
D. Testing is mandatory before any opioid prescription
Correct Answer: A - Ultra-rapid metabolizers may experience
life-threatening toxicity from standard doses
RATIONALE
Ultra-rapid CYP2D6 metabolizers convert codeine to morphine
rapidly, risking respiratory depression. Poor metabolizers (B) may get
little analgesia due to reduced conversion. Genotype significantly
affects efficacy (C). Testing is recommended but not mandatory (D).
Question 5
A patient on long-term opioid therapy for chronic pain develops myoclonus
and hyperalgesia. Which opioid is most likely responsible due to accumulation
of neuroexcitatory metabolites?
A. Morphine
B. Fentanyl
C. Methadone
D. Oxycodone
Correct Answer: A - Morphine
RATIONALE
Morphine-6-glucuronide and morphine-3-glucuronide can accumulate
in renal impairment, causing myoclonus and hyperalgesia. Fentanyl
(B) has no active metabolites. Methadone (C) can cause QT
prolongation but not typically myoclonus from metabolites.
Oxycodone (D) metabolites are less neuroexcitatory.
Question 6
Which antidepressant is most appropriate for a patient with chronic pain and
insomnia, given its dual mechanism?
A. Fluoxetine
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