Sedative-Hypnotics — MCQs
Which drug selectively acts on GABA-A receptors to induce sleep with minimal effects on sleep architecture?
Diazepam poisoning is treated by:
Which of the following inhalational agent is contraindicated in a patient with history of epilepsy -
Which anxiolytic acts through 5-HT1A receptor partial agonism without exhibiting significant anticonvulsant or muscle relaxant properties?
Which of the following statements about flumazenil is correct?
Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?
Which sedative is most appropriate in a patient with hepatic impairment?
Antagonist of benzodiazepine is?
Shortest acting non benzodiazepine sedative is
Match the following: Column A: a. Beta 1 b. Beta 2 c. Beta 3 Column B: 1. Mirabegron 2. Betaxolol 3. Salbutamol
Sedative-Hypnotics Indian Medical PG Practice Questions and MCQs
Question 1: Which drug selectively acts on GABA-A receptors to induce sleep with minimal effects on sleep architecture?
- A. Zolpidem (Correct Answer)
- B. Phenobarbitone
- C. Buspirone
- D. Diazepam
Explanation: ***Zolpidem*** - **Zolpidem** is a non-benzodiazepine hypnotic that selectively binds to the **omega-1 subtype of GABA-A receptors**, primarily mediating sedation. - This selective action results in sleep induction with **minimal disruption of normal sleep architecture**, making it preferable for insomnia. *Phenobarbitone* - **Phenobarbitone** is a barbiturate that non-selectively enhances GABA-A receptor activity, leading to global CNS depression. - It significantly **disturbs sleep architecture**, reducing REM sleep and slow-wave sleep, and carries a higher risk of dependence and overdose. *Buspirone* - **Buspirone** is an anxiolytic that acts as a partial agonist at **5-HT1A serotonin receptors** and has no direct activity at GABA-A receptors. - It treats generalized anxiety disorder but does **not induce sleep** and is not used as a hypnotic. *Diazepam* - **Diazepam** is a benzodiazepine that non-selectively binds to various subunits of the GABA-A receptor, enhancing GABAergic transmission. - While it induces sleep, it also **significantly alters sleep architecture** (reducing REM and slow-wave sleep) and has a longer half-life, increasing the risk of daytime sedation.
Question 2: Diazepam poisoning is treated by:
- A. Resins
- B. Hemofiltration
- C. Charcoal
- D. Flumazenil (Correct Answer)
Explanation: ***Flumazenil*** - **Flumazenil** is a **benzodiazepine receptor antagonist** that competitively binds to the benzodiazepine binding site on the GABA-A receptor, reversing the effects of diazepam. - It is used in cases of severe benzodiazepine overdose causing **respiratory depression** or **severe sedation**. *Resins* - **Resins**, such as **cholestyramine**, are typically used to bind toxins or drugs in the **gastrointestinal tract** that undergo enterohepatic recirculation. - They are generally not effective for reversing the central nervous system depression caused by a benzodiazepine overdose. *Hemofiltration* - **Hemofiltration** is a form of renal replacement therapy used to remove small and middle molecular weight substances from the blood. - While it can remove some drugs, **diazepam** is highly **lipophilic** and extensively **protein-bound**, making it poorly amenable to removal by hemofiltration. *Charcoal* - **Activated charcoal** is used to prevent the absorption of ingested toxins from the gastrointestinal tract. - It is effective when administered soon after ingestion but does not reverse the established effects of an absorbed drug like diazepam in an overdose situation.
Question 3: Which of the following inhalational agent is contraindicated in a patient with history of epilepsy -
- A. Enflurane (Correct Answer)
- B. Isoflurane
- C. Sevoflurane
- D. Halothane
Explanation: ***Enflurane*** - **Enflurane** is known to cause **epileptiform EEG changes** and seizures, especially at high concentrations or in the presence of hypocarbia. - This proconvulsant effect makes it contraindicated in patients with a history of **epilepsy** due to the risk of inducing or exacerbating seizure activity. *Isoflurane* - **Isoflurane** is generally considered safe in patients with epilepsy as it has **minimal proconvulsant activity** and can even have anticonvulsant properties. - It does not typically produce epileptiform EEG patterns or clinical seizures. *Sevoflurane* - **Sevoflurane** is also considered safe in epileptic patients and is widely used for induction and maintenance of anesthesia. - While there have been reports of seizure-like activity during **Sevoflurane** induction, these are rare and usually resolve quickly without long-term complications. *Halothane* - **Halothane** is largely historical and not commonly used today due to its association with **hepatotoxicity** and cardiac dysrhythmias. - It does not typically induce seizures and historically was not contraindicated in patients with epilepsy based on seizure risk.
Question 4: Which anxiolytic acts through 5-HT1A receptor partial agonism without exhibiting significant anticonvulsant or muscle relaxant properties?
- A. Diazepam
- B. Zolpidem
- C. Phenobarbitone
- D. Buspirone (Correct Answer)
Explanation: ***Buspirone*** - **Buspirone** is a unique anxiolytic that primarily acts as a **partial agonist at 5-HT1A receptors**. - Unlike benzodiazepines, it lacks significant **anticonvulsant**, **muscle relaxant**, or **sedative-hypnotic properties** and does not lead to physical dependence or withdrawal. *Diazepam* - **Diazepam** is a **benzodiazepine** that acts by enhancing the effect of **GABA** at GABA-A receptors, leading to significant anxiolytic, sedative, muscle relaxant, and anticonvulsant effects. - It does not primarily act via **5-HT1A receptor partial agonism**. *Zolpidem* - **Zolpidem** is a **non-benzodiazepine hypnotic** that selectively binds to the **GABA-A receptor** subunit, primarily mediating sedative effects. - While it's used for insomnia, it doesn't primarily act as a **5-HT1A partial agonist** and is not typically used for its anxiolytic properties in the same way as buspirone. *Phenobarbitone* - **Phenobarbitone** is a **barbiturate** that acts by prolonging the opening of **chloride channels** associated with GABA-A receptors, leading to strong sedative, hypnotic, and anticonvulsant effects. - Its mechanism of action is distinct from **5-HT1A receptor partial agonism**, and it carries a high risk of dependence and overdose.
Question 5: Which of the following statements about flumazenil is correct?
- A. Can be used in barbiturate poisoning
- B. Specific antidote for opiate overdose
- C. Can be used in benzodiazepine overdose (Correct Answer)
- D. None of the options
Explanation: ***Can be used in benzodiazepine overdose*** - **Flumazenil** is a **competitive antagonist** at the **GABA-A receptor**, specifically designed to reverse the effects of **benzodiazepines**. - It binds to the same receptor site as benzodiazepines, effectively blocking their sedative and anxiolytic actions, making it useful in emergent overdose situations. *Can be used in barbiturate poisoning* - **Flumazenil** is **ineffective** in **barbiturate overdose** because barbiturates bind to a different site on the GABA-A receptor than benzodiazepines. - Barbiturates enhance **GABAergic activity** through a distinct mechanism, which flumazenil does not antagonize. *Specific antidote for opiate overdose* - The **specific antidote for opiate overdose** is **naloxone**, which acts as an opioid receptor antagonist. - **Flumazenil** has **no affinity** for opioid receptors and thus no role in reversing opiate toxicity. *None of the options* - This option is incorrect because **flumazenil** is indeed used for **benzodiazepine overdose**, as described above. - Its specific mechanism of action targets benzodiazepine-induced central nervous system depression.
Question 6: Which of the following is the FIRST-LINE antiemetic drug most commonly used for post-operative nausea and vomiting (PONV) prophylaxis?
- A. Lorazepam
- B. Metoclopramide
- C. Promethazine
- D. Ondansetron (Correct Answer)
Explanation: ***Ondansetron*** - **Ondansetron** is a **5-HT3 receptor antagonist** and is considered a first-line agent due to its high efficacy and favorable side effect profile in preventing PONV. - It works by blocking serotonin receptors in the **chemoreceptor trigger zone** and the **gastrointestinal tract**, reducing the sensation of nausea and vomiting. *Lorazepam* - **Lorazepam** is a **benzodiazepine** primarily used for its **anxiolytic** and **sedative effects**, and sometimes as an adjunct for refractory nausea, but not as a first-line antiemetic for PONV prophylaxis. - While it can help indirectly by reducing anxiety, it does not directly target the key pathways involved in PONV as effectively as 5-HT3 antagonists. *Phenytoin* - **Phenytoin** is an **anticonvulsant** medication used to prevent seizures and has no role in the direct treatment or prophylaxis of PONV. - It primarily acts on voltage-gated sodium channels in neurons and does not possess antiemetic properties. *Metoclopramide* - **Metoclopramide** is a **dopamine D2 receptor antagonist** and a **prokinetic agent** that can be used for PONV, particularly when gastric stasis is a concern. - However, it is generally considered a second-line agent due to the risk of **extrapyramidal side effects**, especially with higher doses or prolonged use. *Promethazine* - **Promethazine** is a **first-generation antihistamine** with **antidopaminergic** and **anticholinergic properties** that can be effective for nausea and vomiting. - It is often used as a rescue antiemetic or in combination therapy, but its sedative effects and potential for extrapyramidal symptoms make it less preferable as a first-line prophylactic agent compared to ondansetron.
Question 7: Which sedative is most appropriate in a patient with hepatic impairment?
- A. Midazolam
- B. Lorazepam (Correct Answer)
- C. Zolpidem
- D. Diazepam
Explanation: ***Lorazepam*** - **Lorazepam** is primarily metabolized by **glucuronidation**, a phase II metabolic pathway that is relatively preserved in most forms of hepatic impairment - This makes it a safer choice in patients with **liver disease** compared to other benzodiazepines that rely heavily on oxidative metabolism - Preferred sedative in cirrhosis and acute liver failure *Midazolam* - **Midazolam** is primarily metabolized by the **cytochrome P450 3A4 (CYP3A4)** enzyme system in the liver - Hepatic impairment can significantly reduce **CYP3A4 activity**, leading to prolonged half-life, increased sedative effects, and accumulation of the drug - Should be avoided or dose-reduced in hepatic impairment *Zolpidem* - **Zolpidem** is extensively metabolized by **hepatic cytochrome P450 enzymes**, particularly CYP3A4 and CYP2C9 - In patients with **hepatic impairment**, its clearance is significantly reduced, necessitating dose reduction to avoid excessive sedation and adverse effects - Maximum dose should be limited to 5 mg in hepatic dysfunction *Diazepam* - **Diazepam** undergoes extensive **hepatic oxidative metabolism** via CYP2C19 and CYP3A4 to active metabolites such as **desmethyldiazepam**, which also have long half-lives - In patients with **liver disease**, this metabolism is impaired, leading to prolonged drug action, increased sedation, and accumulation of the parent drug and active metabolites - Active metabolites can accumulate for days to weeks in hepatic impairment
Question 8: Antagonist of benzodiazepine is?
- A. Buspirone
- B. Zolpidem
- C. Ramelteon
- D. Flumazenil (Correct Answer)
Explanation: ***Flumazenil*** - **Flumazenil** is a competitive antagonist at the **GABA-A receptor**, where benzodiazepines exert their effects. - It is used to reverse the sedative and respiratory depressant effects of **benzodiazepine overdose** or to aid in recovery from general anesthesia induced with benzodiazepines. *Buspirone* - **Buspirone** is an anxiolytic agent that acts primarily as a **selective serotonin 5-HT1A receptor partial agonist**, with no direct benzodiazepine receptor activity. - It is used for generalized anxiety disorder but does not reverse benzodiazepine effects. *Zolpidem* - **Zolpidem** is a **non-benzodiazepine hypnotic** (Z-drug) that selectively agonizes the **alpha-1 subunit of the GABA-A receptor**, exhibiting hypnotic effects. - While it acts on the GABA-A receptor, it is an agonist, not an antagonist, and thus exaggerates rather than reverses benzodiazepine-like effects. *Ramelteon* - **Ramelteon** is a **melatonin receptor agonist** that acts on MT1 and MT2 receptors in the suprachiasmatic nucleus. - It helps regulate the sleep-wake cycle and is used for insomnia, but it has no interaction with the benzodiazepine receptor.
Question 9: Shortest acting non benzodiazepine sedative is
- A. Zaleplon (Correct Answer)
- B. Eszopiclone
- C. Zopiclone
- D. Zolpidem
Explanation: ***Zaleplon*** - Has the shortest **half-life** (approximately 1 hour) among the non-benzodiazepine hypnotics, allowing for rapid elimination. - This quick elimination makes it ideal for patients who have difficulty **falling asleep** but do not need prolonged sedation. - Particularly useful for **middle-of-the-night** dosing due to its ultra-short duration. *Eszopiclone* - Has a half-life of about 6 hours, which is significantly longer than Zaleplon. - It's the S-enantiomer of zopiclone and is used for both **sleep onset and maintenance**. - Provides more sustained sleep throughout the night compared to Zaleplon. *Zopiclone* - Has a half-life of about 5-6 hours, which is considerably longer than Zaleplon. - It's used for the short-term treatment of **insomnia** and helps both with sleep onset and maintenance. - May cause a characteristic **bitter metallic taste** as a side effect. *Zolpidem* - Has a half-life of 2-3 hours, making it longer-acting than Zaleplon. - It's commonly prescribed for problems with **sleep initiation** and occasionally for sleep maintenance. - Available in extended-release formulations for prolonged action.
Question 10: Match the following: Column A: a. Beta 1 b. Beta 2 c. Beta 3 Column B: 1. Mirabegron 2. Betaxolol 3. Salbutamol
- A. a-2, b-3 ,c-1 (Correct Answer)
- B. a-2, b-1, c-3
- C. a-3, b-2, c-1
- D. a-3, b-1, c-2
Explanation: ***a-2, b-3, c-1*** - This pairing correctly matches **Betaxolol** with **Beta 1 selective** antagonism, **Salbutamol** with **Beta 2 selective** agonism, and **Mirabegron** with **Beta 3 selective** agonism. - **Betaxolol** is a beta-1 selective adrenergic receptor antagonist, primarily used in ophthalmology to reduce intraocular pressure and as an antihypertensive. **Salbutamol** is a selective beta-2 adrenergic agonist used as a bronchodilator in asthma and COPD, causing relaxation of bronchial smooth muscle. **Mirabegron** is a selective beta-3 adrenergic agonist used to treat overactive bladder by relaxing the detrusor muscle. *a-2, b-1, c-3* - This option incorrectly assigns **Mirabegron** to Beta 2. Mirabegron is a **Beta 3 selective agonist**. - It also incorrectly assigns **Salbutamol** to Beta 3. Salbutamol is a **Beta 2 selective agonist**. *a-3, b-2, c-1* - This option incorrectly assigns **Salbutamol** to Beta 1. Salbutamol is a **Beta 2 selective agonist**. - It also incorrectly assigns **Betaxolol** to Beta 2. Betaxolol is a **Beta 1 selective antagonist**. *a-3, b-1, c-2* - This option incorrectly assigns **Salbutamol** to Beta 1 and **Betaxolol** to Beta 3. - **Salbutamol** is a Beta 2 selective agonist, and **Betaxolol** is a Beta 1 selective antagonist.
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