NURS 5359 Psychopharmacology
Exam 3 Questions and Answers| Updated| Pass Guaranteed
.
1. What is the primary mechanism of action of benzodiazepines at the GABA-A
receptor?
A. Direct opening of the chloride channel in the absence of GABA
B. Positive allosteric modulation that increases the FREQUENCY of chloride
channel opening when GABA is bound
C. Increasing the DURATION of chloride channel opening
D. Blocking presynaptic reuptake of GABA
Answer: B. Positive allosteric modulation that increases the FREQUENCY of
chloride channel opening when GABA is bound
Rationale: Benzodiazepines do not activate the receptor on their own. They
enhance the effect of endogenous GABA by increasing how often the chloride
channel opens, producing neuronal hyperpolarization and CNS inhibition.
2. The GABA-A receptor is best classified as which type of receptor?
A. A ligand-gated chloride ion channel (pentameric)
B. A G-protein coupled receptor
C. A voltage-gated sodium channel
D. A ligand-gated cation channel permeable to calcium
Answer: A. A ligand-gated chloride ion channel (pentameric)
Rationale: GABA-A is an ionotropic, ligand-gated Cl- channel made of five
subunits. GABA-B, by contrast, is a G-protein coupled receptor.
Page 1
,3. Where do benzodiazepines bind on the GABA-A receptor complex?
A. At the same orthosteric site where GABA binds, between the alpha and beta
subunits
B. Inside the chloride pore itself
C. On the intracellular side of the beta subunit
D. At the interface of the alpha and gamma-2 subunits (the benzodiazepine site)
Answer: D. At the interface of the alpha and gamma-2 subunits (the
benzodiazepine site)
Rationale: The benzodiazepine site is distinct from the GABA site. Because it is an
allosteric site, benzodiazepines only work when GABA is present.
4. Which is the net effect of increased chloride influx through the GABA-A
receptor?
A. Neuronal depolarization and increased firing
B. Increased glutamate release
C. Neuronal hyperpolarization and decreased neuronal excitability
D. Increased dopamine release in the nucleus accumbens
Answer: C. Neuronal hyperpolarization and decreased neuronal excitability
Rationale: Chloride entering the neuron makes the inside more negative
(hyperpolarized), so the neuron is less likely to fire. This produces anxiolytic,
sedative, anticonvulsant and muscle-relaxant effects.
5. How do barbiturates differ from benzodiazepines at the GABA-A receptor?
A. Barbiturates increase the FREQUENCY of channel opening only
B. Barbiturates increase the DURATION of channel opening and can open the
channel directly at high doses
C. Barbiturates block the chloride channel
D. Barbiturates are GABA-A antagonists
Page 2
,Answer: B. Barbiturates increase the DURATION of channel opening and can
open the channel directly at high doses
Rationale: Barbiturates prolong channel opening and at high doses act directly
without GABA, which explains their narrow therapeutic index and fatal overdose
risk. Benzodiazepines depend on GABA and are far safer when taken alone.
6. Why are benzodiazepines safer in overdose (when taken alone) than
barbiturates?
A. They have a ceiling effect because they require endogenous GABA to work
B. They have no effect on respiration at any dose
C. They are not metabolized by the liver
D. They are GABA-B agonists
Answer: A. They have a ceiling effect because they require endogenous GABA to
work
Rationale: As positive allosteric modulators, benzodiazepines cannot exceed the
inhibition produced by available GABA. Overdose becomes dangerous mainly
when combined with alcohol, opioids or other CNS depressants.
7. Which benzodiazepine is preferred for a patient with significant hepatic
impairment?
A. Diazepam
B. Chlordiazepoxide
C. Clorazepate
D. Lorazepam
Answer: D. Lorazepam
Rationale: Lorazepam is metabolized by glucuronidation (phase II), which is
relatively preserved in liver disease, and it has no active metabolites. Diazepam
and chlordiazepoxide undergo oxidation and form long-acting active metabolites
that accumulate.
Page 3
, 8. Which group of benzodiazepines is eliminated mainly by glucuronidation and
has NO active metabolites (the 'LOT' drugs)?
A. Diazepam, chlordiazepoxide, clorazepate
B. Alprazolam, triazolam, midazolam
C. Lorazepam, oxazepam, temazepam
D. Flurazepam, quazepam, clonazepam
Answer: C. Lorazepam, oxazepam, temazepam
Rationale: LOT = Lorazepam, Oxazepam, Temazepam. They bypass CYP oxidation,
so they are favored in hepatic impairment and in older adults when a
benzodiazepine is unavoidable.
9. Diazepam has a prolonged clinical effect primarily because of which factor?
A. Extensive renal tubular reabsorption
B. Active metabolites such as desmethyldiazepam with a very long half-life
C. Irreversible receptor binding
D. Low lipid solubility
Answer: B. Active metabolites such as desmethyldiazepam with a very long half-
life
Rationale: Diazepam is converted to desmethyldiazepam (nordiazepam), which
can have a half-life of up to about 100 hours, leading to accumulation with
repeated dosing.
10. Which benzodiazepine is most likely to accumulate and cause oversedation
and falls in an older adult?
A. Diazepam
B. Lorazepam
C. Oxazepam
D. Temazepam
Page 4
Exam 3 Questions and Answers| Updated| Pass Guaranteed
.
1. What is the primary mechanism of action of benzodiazepines at the GABA-A
receptor?
A. Direct opening of the chloride channel in the absence of GABA
B. Positive allosteric modulation that increases the FREQUENCY of chloride
channel opening when GABA is bound
C. Increasing the DURATION of chloride channel opening
D. Blocking presynaptic reuptake of GABA
Answer: B. Positive allosteric modulation that increases the FREQUENCY of
chloride channel opening when GABA is bound
Rationale: Benzodiazepines do not activate the receptor on their own. They
enhance the effect of endogenous GABA by increasing how often the chloride
channel opens, producing neuronal hyperpolarization and CNS inhibition.
2. The GABA-A receptor is best classified as which type of receptor?
A. A ligand-gated chloride ion channel (pentameric)
B. A G-protein coupled receptor
C. A voltage-gated sodium channel
D. A ligand-gated cation channel permeable to calcium
Answer: A. A ligand-gated chloride ion channel (pentameric)
Rationale: GABA-A is an ionotropic, ligand-gated Cl- channel made of five
subunits. GABA-B, by contrast, is a G-protein coupled receptor.
Page 1
,3. Where do benzodiazepines bind on the GABA-A receptor complex?
A. At the same orthosteric site where GABA binds, between the alpha and beta
subunits
B. Inside the chloride pore itself
C. On the intracellular side of the beta subunit
D. At the interface of the alpha and gamma-2 subunits (the benzodiazepine site)
Answer: D. At the interface of the alpha and gamma-2 subunits (the
benzodiazepine site)
Rationale: The benzodiazepine site is distinct from the GABA site. Because it is an
allosteric site, benzodiazepines only work when GABA is present.
4. Which is the net effect of increased chloride influx through the GABA-A
receptor?
A. Neuronal depolarization and increased firing
B. Increased glutamate release
C. Neuronal hyperpolarization and decreased neuronal excitability
D. Increased dopamine release in the nucleus accumbens
Answer: C. Neuronal hyperpolarization and decreased neuronal excitability
Rationale: Chloride entering the neuron makes the inside more negative
(hyperpolarized), so the neuron is less likely to fire. This produces anxiolytic,
sedative, anticonvulsant and muscle-relaxant effects.
5. How do barbiturates differ from benzodiazepines at the GABA-A receptor?
A. Barbiturates increase the FREQUENCY of channel opening only
B. Barbiturates increase the DURATION of channel opening and can open the
channel directly at high doses
C. Barbiturates block the chloride channel
D. Barbiturates are GABA-A antagonists
Page 2
,Answer: B. Barbiturates increase the DURATION of channel opening and can
open the channel directly at high doses
Rationale: Barbiturates prolong channel opening and at high doses act directly
without GABA, which explains their narrow therapeutic index and fatal overdose
risk. Benzodiazepines depend on GABA and are far safer when taken alone.
6. Why are benzodiazepines safer in overdose (when taken alone) than
barbiturates?
A. They have a ceiling effect because they require endogenous GABA to work
B. They have no effect on respiration at any dose
C. They are not metabolized by the liver
D. They are GABA-B agonists
Answer: A. They have a ceiling effect because they require endogenous GABA to
work
Rationale: As positive allosteric modulators, benzodiazepines cannot exceed the
inhibition produced by available GABA. Overdose becomes dangerous mainly
when combined with alcohol, opioids or other CNS depressants.
7. Which benzodiazepine is preferred for a patient with significant hepatic
impairment?
A. Diazepam
B. Chlordiazepoxide
C. Clorazepate
D. Lorazepam
Answer: D. Lorazepam
Rationale: Lorazepam is metabolized by glucuronidation (phase II), which is
relatively preserved in liver disease, and it has no active metabolites. Diazepam
and chlordiazepoxide undergo oxidation and form long-acting active metabolites
that accumulate.
Page 3
, 8. Which group of benzodiazepines is eliminated mainly by glucuronidation and
has NO active metabolites (the 'LOT' drugs)?
A. Diazepam, chlordiazepoxide, clorazepate
B. Alprazolam, triazolam, midazolam
C. Lorazepam, oxazepam, temazepam
D. Flurazepam, quazepam, clonazepam
Answer: C. Lorazepam, oxazepam, temazepam
Rationale: LOT = Lorazepam, Oxazepam, Temazepam. They bypass CYP oxidation,
so they are favored in hepatic impairment and in older adults when a
benzodiazepine is unavoidable.
9. Diazepam has a prolonged clinical effect primarily because of which factor?
A. Extensive renal tubular reabsorption
B. Active metabolites such as desmethyldiazepam with a very long half-life
C. Irreversible receptor binding
D. Low lipid solubility
Answer: B. Active metabolites such as desmethyldiazepam with a very long half-
life
Rationale: Diazepam is converted to desmethyldiazepam (nordiazepam), which
can have a half-life of up to about 100 hours, leading to accumulation with
repeated dosing.
10. Which benzodiazepine is most likely to accumulate and cause oversedation
and falls in an older adult?
A. Diazepam
B. Lorazepam
C. Oxazepam
D. Temazepam
Page 4
