CNS pharmacology: sedatives, hypnotics and anxiolytics MCQs With Answer

CNS pharmacology: sedatives, hypnotics and anxiolytics MCQs With Answer

Introduction: This question set is designed specifically for M.Pharm students preparing for Advanced Pharmacology-I exams. It focuses on sedatives, hypnotics and anxiolytics, integrating receptor pharmacology, molecular mechanisms, pharmacokinetics, clinical indications, adverse effects, dependence and drug interactions. Questions emphasize deeper understanding—such as subunit selectivity of GABA-A receptors, differences between benzodiazepines, barbiturates and Z‑drugs, and practical considerations in special populations. Each MCQ includes concise options and the correct answer to facilitate rapid revision, critical thinking and application of concepts to clinical and research contexts.

Q1. What is the primary allosteric effect of benzodiazepines on the GABA-A receptor?

• Increase the duration of chloride channel opening
• Increase the frequency of chloride channel opening
• Directly open the chloride channel in absence of GABA
• Inhibit GABA reuptake into presynaptic terminals

Correct Answer: Increase the frequency of chloride channel opening

Q2. Flumazenil acts pharmacologically as which of the following at the benzodiazepine binding site?

• Full agonist
• Partial agonist
• Competitive antagonist
• Non-competitive negative allosteric modulator

Correct Answer: Competitive antagonist

Q3. Z‑drugs (zolpidem, zaleplon, zopiclone) show preferential binding to which GABA-A alpha subunit associated primarily with sedation?

• Alpha1
• Alpha2
• Alpha3
• Alpha5

Correct Answer: Alpha1

Q4. Compared to benzodiazepines, barbiturates at increasing concentrations primarily alter GABA-A receptor function by:

• Increasing chloride channel opening frequency
• Increasing chloride channel opening duration and directly activating the channel at high doses
• Blocking chloride conductance
• Selective antagonism of the benzodiazepine binding site

Correct Answer: Increasing chloride channel opening duration and directly activating the channel at high doses

Q5. Buspirone’s anxiolytic effect is mainly mediated through which receptor action?

• GABA-A positive modulation
• 5-HT1A partial agonism
• Benzodiazepine receptor agonism
• D2 receptor antagonism

Correct Answer: 5-HT1A partial agonism

Q6. Which hypnotic is least likely to cause residual next‑day sedation due to its very short elimination half‑life?

• Zolpidem
• Zaleplon
• Eszopiclone
• Temazepam

Correct Answer: Zaleplon

Q7. Which benzodiazepine is well known for rapid distribution and formation of active metabolites leading to prolonged effects?

• Lorazepam
• Clonazepam
• Diazepam
• Oxazepam

Correct Answer: Diazepam

Q8. Which benzodiazepine is often preferred in elderly patients or those with hepatic impairment because it is primarily conjugated and has no active metabolites?

• Diazepam
• Flurazepam
• Lorazepam
• Chlordiazepoxide

Correct Answer: Lorazepam

Q9. Co-administration of which class of anxiolytics with opioids markedly increases the risk of life‑threatening respiratory depression?

• Benzodiazepines
• Buspirone
• SSRIs
• Melatonin receptor agonists

Correct Answer: Benzodiazepines

Q10. Ramelteon produces hypnotic effects primarily by agonism at which receptors?

• GABA-A alpha1 subunit
• MT1 and MT2 melatonin receptors
• 5-HT2A receptors
• Histamine H1 receptors

Correct Answer: MT1 and MT2 melatonin receptors

Q11. During chronic benzodiazepine therapy, tolerance most rapidly develops to which clinical effect?

• Anxiolytic effect
• Hypnotic/sedative effect
• Muscle relaxant effect
• Anticonvulsant effect

Correct Answer: Hypnotic/sedative effect

Q12. Which statement about flumazenil is correct?

• It reverses barbiturate-induced respiratory depression
• It is a benzodiazepine receptor antagonist that can precipitate seizures in benzodiazepine-dependent patients
• It is an irreversible inhibitor of the benzodiazepine site
• It potentiates opioid analgesia

Correct Answer: It is a benzodiazepine receptor antagonist that can precipitate seizures in benzodiazepine-dependent patients

Q13. Which benzodiazepine is least suitable for a patient with significant hepatic impairment?

• Lorazepam
• Oxazepam
• Diazepam
• Temazepam

Correct Answer: Diazepam

Q14. Which hypnotic has been most frequently associated with complex sleep-related behaviours such as sleep‑walking and sleep‑eating?

• Zolpidem
• Zaleplon
• Ramelteon
• Triazolam

Correct Answer: Zolpidem

Q15. A key clinical advantage of buspirone over benzodiazepines for generalized anxiety disorder is:

• Rapid onset within minutes
• Lack of dependence and abuse potential
• Potentiation of alcohol effects
• Usefulness in status epilepticus

Correct Answer: Lack of dependence and abuse potential

Q16. Which GABA-A alpha subunit has been most strongly implicated in mediating the anxiolytic effects of benzodiazepines?

• Alpha1
• Alpha2
• Alpha4
• Alpha6

Correct Answer: Alpha2

Q17. In significant phenobarbital overdose, enhanced elimination is facilitated by which intervention?

• Flumazenil administration
• Urinary alkalinization and, if necessary, hemodialysis
• Naloxone infusion
• Avoiding activated charcoal at all costs

Correct Answer: Urinary alkalinization and, if necessary, hemodialysis

Q18. Compared with classical benzodiazepines, Z‑drugs differ primarily by:

• Potentiating glycine receptors selectively
• Relatively selective binding to GABA-A receptors containing the alpha1 subunit, producing mainly hypnotic effects
• Inhibiting serotonin reuptake
• Antagonizing NMDA receptors

Correct Answer: Relatively selective binding to GABA-A receptors containing the alpha1 subunit, producing mainly hypnotic effects

Q19. Chronic benzodiazepine use most consistently alters sleep architecture by:

• Decreasing REM sleep duration
• Increasing REM sleep duration
• Increasing slow-wave sleep
• No change in sleep architecture

Correct Answer: Decreasing REM sleep duration

Q20. Regarding barbiturate dependence and withdrawal, which statement is accurate?

• Withdrawal is generally mild and only produces anxiety
• Withdrawal can be life-threatening with seizures and delirium tremens–like features
• Physical dependence does not occur with long-term barbiturate use
• Withdrawal symptoms are easily reversed with naloxone

Correct Answer: Withdrawal can be life-threatening with seizures and delirium tremens–like features

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