Substance Use Disorders Practice Questions

Q: Which anticraving agent acts as an NMDA antagonist?

Acamprosate. ### Explanation **Correct Option: B. Acamprosate** Acamprosate is a structural analogue of GABA used for the maintenance of abstinence in alcohol dependence. Chronic alcohol consumption leads to a compensatory downregulation of GABA receptors and upregulation of NMDA (glutamate) receptors. When alcohol is withdrawn, this results in a hyper-excitable state. Acamprosate works by **antagonizing NMDA receptors** and potentially modulating GABA-A receptors, thereby restoring the neurochemical balance (homeostasis) between excitatory and inhibitory neurotransmission. **Incorrect Options:** * **A. Naltrexone:** This is an **opioid receptor antagonist** (primarily at the $\mu$ receptor). It reduces the "reward" or euphoria associated with alcohol consumption by blocking endogenous opioid pathways. * **C. Baclofen:** This is a **GABA-B receptor agonist**. While used off-label to reduce cravings and withdrawal symptoms in alcohol use disorder, its primary mechanism is not NMDA antagonism. * **D. Topiramate:** This is an antiepileptic that acts by facilitating GABA-A neurotransmission and antagonizing **AMPA/Kainate** glutamate receptors (not primarily NMDA). **High-Yield Clinical Pearls for NEET-PG:** * **Acamprosate** is the drug of choice for maintaining abstinence in patients with **liver disease** (as it is renally excreted) but is contraindicated in **renal failure** (CrCl < 30 mL/min). * **Naltrexone** is preferred for patients who want to reduce heavy drinking ("harm reduction") but is contraindicated in **acute hepatitis or liver failure**. * **Disulfiram** is an aversive agent (aldehyde dehydrogenase inhibitor) and does *not* reduce cravings; it works through fear of the Disulfiram-Ethanol Reaction (DER).

Q: During alcohol withdrawal, which signs or symptoms typically appear last?

Delirium tremens. The timeline of alcohol withdrawal is a high-yield topic for NEET-PG, as symptoms follow a predictable chronological sequence based on the decline in blood alcohol levels. ### **Explanation of the Correct Answer** **Delirium Tremens (DT)** is the most severe and **last** manifestation of alcohol withdrawal. It typically occurs **48 to 96 hours** after the last drink. It is characterized by clouding of consciousness (delirium), autonomic hyperactivity (tachycardia, hypertension, fever), and vivid hallucinations. The underlying mechanism involves a profound rebound of the NMDA (glutamate) system and downregulation of GABA receptors after chronic suppression by alcohol. ### **Analysis of Incorrect Options** * **A. Cluster Seizures:** These are "rum fits" that typically occur **6 to 48 hours** after cessation. They are usually generalized tonic-clonic seizures and occur much earlier than DTs. * **B. Hallucinations:** Alcoholic hallucinosis occurs **12 to 48 hours** after the last drink. Unlike DTs, the patient’s sensorium is usually clear (they are conscious and oriented), and it precedes the onset of delirium. * **C. Anterograde Amnesia:** This is a hallmark of **Wernicke-Korsakoff Syndrome** (due to Thiamine deficiency), not a standard stage of the acute withdrawal timeline. ### **NEET-PG High-Yield Pearls** * **Chronology Summary:** 1. Insomnia/Tremors (6–12h) 2. Hallucinosis (12–48h) 3. Seizures (6–48h) 4. **Delirium Tremens (48–96h)**. * **Drug of Choice:** Benzodiazepines (e.g., Diazepam, Chlordiazepoxide). * **Liver Failure Patients:** Use **LOT** (Lorazepam, Oxazepam, Temazepam) as they undergo extrahepatic metabolism. * **Mortality:** DT is a medical emergency with a mortality rate of up to 5% if untreated, usually due to cardiovascular collapse or hyperthermia.

Q: A 'bad trip' is most commonly associated with the use of which substance?

LSD. **Explanation:** The term **'bad trip'** refers to a transient, acute adverse psychological reaction characterized by intense anxiety, panic, paranoia, and terrifying hallucinations. This phenomenon is most characteristically and commonly associated with **LSD (Lysergic Acid Diethylamide)**, a potent psychedelic. **Why LSD is the correct answer:** LSD acts primarily as a partial agonist at **5-HT2A receptors**. It causes profound alterations in perception (synesthesia), mood, and thought. A 'bad trip' occurs when these sensory distortions become overwhelming or nightmarish, often leading to a fear of "going crazy" or dying. Management typically involves a "talking down" approach in a quiet environment, or benzodiazepines if the patient is severely agitated. **Analysis of Incorrect Options:** * **Cocaine:** A stimulant that causes euphoria and increased energy. Toxicity leads to sympathetic overactivity (tachycardia, hypertension) and potentially "cocaine bugs" (formication), but not a 'bad trip' in the classic psychedelic sense. * **Cannabis:** While high doses can cause acute panic or "toxic psychosis," it is not the primary substance associated with the clinical definition of a 'bad trip.' * **Heroin:** An opioid that causes CNS depression, euphoria, and sedation ("nodding off"). Toxicity results in respiratory depression and miosis, rather than hallucinogenic crises. **High-Yield Clinical Pearls for NEET-PG:** * **Flashbacks (Hallucinogen Persisting Perception Disorder):** Recurrence of the 'trip' experience weeks or months after the last use of LSD. * **Tolerance:** LSD shows rapid tolerance (tachyphylaxis) but **no physical dependence** or withdrawal symptoms. * **Pupillary findings:** LSD causes **Mydriasis** (dilated pupils), whereas Heroin causes **Miosis** (pinpoint pupils).

Q: Which of the following drugs has no role in opioid detoxification?

Naloxone. ### Explanation The goal of **opioid detoxification** is to manage withdrawal symptoms safely while transitioning a patient off illicit opioids. This is achieved using either opioid agonists (to taper the dose) or non-opioid medications (to manage autonomic symptoms). **Why Naloxone is the Correct Answer:** Naloxone is a **pure opioid antagonist** with a very short half-life. It works by competitively displacing opioids from the mu-receptors. If administered to an opioid-dependent patient, it will **precipitate acute, severe withdrawal**. Therefore, it has no role in detoxification. Its primary clinical uses are the emergency reversal of opioid overdose and as an abuse-deterrent when combined with buprenorphine (Suboxone). **Analysis of Incorrect Options:** * **Methadone (Option B):** A long-acting **full mu-opioid agonist**. It prevents withdrawal symptoms and craving due to its long half-life, allowing for a controlled, gradual taper. * **Buprenorphine (Option C):** A **partial mu-opioid agonist**. It has a high affinity for the receptor but lower intrinsic activity, making it safer than methadone (less respiratory depression) for detoxification and maintenance. * **Clonidine (Option D):** An **alpha-2 adrenergic agonist**. It is a non-opioid medication used to treat the autonomic hyperactivity of withdrawal (tachycardia, hypertension, sweating, and restlessness). **NEET-PG High-Yield Pearls:** * **Drug of Choice for Opioid Overdose:** Naloxone (IV/Intranasal). * **Drug of Choice for Opioid Maintenance in Pregnancy:** Methadone. * **Naltrexone:** Unlike Naloxone, Naltrexone is long-acting and used for **relapse prevention** (post-detoxification), not for active detox. * **COWS Scale:** The Clinical Opiate Withdrawal Scale is used to monitor the severity of withdrawal during detoxification.

Q: All of the following drugs are used to prevent relapse after alcohol de-addiction except?

Fluoxetine. **Explanation:** The goal of alcohol de-addiction therapy is to maintain abstinence and prevent relapse. The drugs used for this purpose are classified as **anti-craving agents** or **aversion therapy agents**. **Why Fluoxetine is the correct answer:** Fluoxetine is a Selective Serotonin Reuptake Inhibitor (SSRI) used primarily for Major Depressive Disorder and Anxiety Disorders. While it may be used to treat comorbid depression in an alcoholic patient, it has **no proven efficacy** in reducing alcohol cravings or preventing relapse in the general population of patients with Alcohol Use Disorder. **Analysis of Incorrect Options:** * **Acamprosate (Option A):** A NMDA receptor antagonist and GABA-A agonist. It restores the chemical balance in the brain disrupted by chronic alcohol use. It is considered the drug of choice for maintaining abstinence, especially in patients with liver disease (as it is renally excreted). * **Disulfiram (Option B):** An aldehyde dehydrogenase inhibitor used for **Aversion Therapy**. It causes the accumulation of acetaldehyde if alcohol is consumed, leading to a highly unpleasant "Disulfiram-Ethanol Reaction" (nausea, tachycardia, flushing), thereby deterring the patient from drinking. * **Naltrexone (Option C):** An opioid receptor antagonist that blocks the "reward" or euphoria associated with drinking. It is highly effective in reducing the frequency of heavy drinking and "slip" episodes. **High-Yield Clinical Pearls for NEET-PG:** * **Acamprosate:** Best for maintaining abstinence; safe in liver disease. * **Naltrexone:** Best for reducing cravings and heavy drinking; **contraindicated in liver failure/acute hepatitis.** * **Disulfiram:** Requires a highly motivated patient and supervised administration; must be started at least 12 hours after the last drink. * **Topiramate & Baclofen:** Other second-line agents used off-label for relapse prevention.

Q: Korsakoff's psychosis is seen in which condition?

Chronic alcoholism. **Explanation:** **Korsakoff’s Psychosis** is a late-stage manifestation of **Wernicke-Korsakoff Syndrome (WKS)**, primarily caused by a severe deficiency of **Thiamine (Vitamin B1)**. In the context of **Chronic Alcoholism (Option C)**, thiamine deficiency occurs due to poor dietary intake, impaired gastrointestinal absorption, and reduced hepatic storage of the vitamin. While Wernicke’s Encephalopathy is the acute, reversible phase, Korsakoff’s Psychosis is the chronic, often irreversible stage characterized by selective anterograde and retrograde amnesia and **confabulation** (filling memory gaps with fabricated stories). **Analysis of Incorrect Options:** * **Option A (Acute Alcoholism):** Acute intoxication presents with cerebellar ataxia and slurred speech but does not cause the structural brain damage (atrophy of mammillary bodies) required for Korsakoff’s. * **Option B (Carbon Monoxide Poisoning):** While CO poisoning causes hypoxia and can lead to delayed neuropsychiatric sequelae (like Parkinsonism or globus pallidus lesions), it is not the classic cause of Korsakoff’s. * **Option D (Multiple Sclerosis):** This is a demyelinating disease of the CNS presenting with optic neuritis or sensory-motor deficits, not a thiamine-related amnestic syndrome. **High-Yield Clinical Pearls for NEET-PG:** 1. **The Triad of Wernicke’s:** Confusion, Ataxia, and Ophthalmoplegia (6th nerve palsy). 2. **Pathology:** Characterized by hemorrhage and atrophy of the **Mammillary bodies** and dorsomedial nucleus of the thalamus. 3. **The "Glucose Rule":** Always administer Thiamine *before* Glucose in a chronic alcoholic to prevent precipitating Wernicke’s Encephalopathy. 4. **Confabulation:** This is the hallmark psychiatric feature of Korsakoff’s, used by the patient to maintain self-esteem despite memory loss.

Q: Which drug is used in the treatment of smoking and tobacco addiction cessation?

Varenicline. **Explanation:** **Varenicline** is the correct answer as it is a first-line pharmacological agent specifically approved for smoking cessation. Its mechanism of action involves being a **selective partial agonist at the α4β2 nicotinic acetylcholine receptors**. By partially stimulating these receptors, it reduces withdrawal symptoms (agonist effect) while simultaneously blocking the binding of nicotine from cigarettes, thereby reducing the "reward" or reinforcement associated with smoking (antagonist effect). **Analysis of Incorrect Options:** * **Acamprosate:** Used for the maintenance of abstinence in **Alcohol Use Disorder**. It acts as a glutamate modulator (NMDA receptor antagonist) to restore the GABA/glutamate balance disrupted by chronic alcohol use. * **Baclofen:** A GABA-B receptor agonist primarily used as a muscle relaxant. While it is sometimes used off-label to reduce cravings in alcohol or opioid dependence, it is not a standard treatment for tobacco cessation. * **Naltrexone:** An opioid receptor antagonist used in the treatment of **Alcohol Dependence** (to reduce craving/heavy drinking) and **Opioid Dependence** (to prevent relapse). **High-Yield Clinical Pearls for NEET-PG:** * **First-line agents for Smoking Cessation:** Nicotine Replacement Therapy (NRT), Varenicline, and Bupropion (an atypical antidepressant). * **Varenicline Side Effects:** Most common is nausea; it was previously associated with neuropsychiatric symptoms (suicidal ideation), though recent data suggests these risks are lower than initially feared. * **Bupropion Contraindication:** Avoid in patients with a history of seizures or eating disorders (bulimia/anorexia), as it lowers the seizure threshold. * **Cytisine:** Another partial nicotinic agonist (similar to Varenicline) gaining importance in recent literature.

Question 1

Which anticraving agent acts as an NMDA antagonist?

Accepted Answer

Acamprosate

Answer

Naltrexone

Answer

Baclofen

Answer

Topiramate

Question 2

During alcohol withdrawal, which signs or symptoms typically appear last?

Accepted Answer

Delirium tremens

Answer

Cluster seizures

Answer

Hallucinations

Answer

Anterograde amnesia

Question 3

A 'bad trip' is most commonly associated with the use of which substance?

Accepted Answer

LSD

Answer

Cocaine

Answer

Cannabis

Answer

Heroin

Question 4

Which of the following drugs has no role in opioid detoxification?

Accepted Answer

Naloxone

Answer

Methadone

Answer

Buprenorphine

Answer

Clonidine

Question 5

Which drug is NOT used in the treatment of alcohol dependence?

Accepted Answer

Diazepam

Answer

Disulfiram

Answer

Acamprosate

Answer

Naltrexone

Question 6

All of the following drugs are used to prevent relapse after alcohol de-addiction except?

Accepted Answer

Fluoxetine

Answer

Acamprosate

Answer

Disulfiram

Answer

Naltrexone

Question 7

A known alcoholic is brought to the emergency department by his wife. The person has not consumed alcohol for the past two days due to religious reasons. The person complained of nausea, vomiting, and dizziness. On the second day, he developed seizures that progressed to generalized tonic-clonic seizures (GTCs). Which of the following would be the best medication to manage the patient's seizures?

Accepted Answer

Diazepam

Answer

Sodium valproate

Answer

Phenytoin

Answer

Clonidine

Question 8

A 46-year-old chronic alcoholic, one day after abstinence from alcohol, presents to casualty with restlessness, seizures, coarse tremors, inability to recognize the doctor, and a belief of being in jail. He also complains of uncontrollable fear of being murdered, insomnia, and insects crawling over his body. What is the probable diagnosis?

Accepted Answer

Delirium tremens

Answer

Alcoholic seizures (rum fits)

Answer

Korsakoff's psychosis

Answer

Alcoholic hallucinosis

Question 9

Korsakoff's psychosis is seen in which condition?

Accepted Answer

Chronic alcoholism

Answer

Acute alcoholism

Answer

Carbon monoxide poisoning

Answer

Multiple sclerosis

Question 10

Which drug is used in the treatment of smoking and tobacco addiction cessation?

Accepted Answer

Varenicline

Answer

Acamprosate

Answer

Baclofen

Answer

Naltrexone

Substance Use Disorders — MCQs

Substance Use Disorders — MCQs

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