Drugs for Dementia — MCQs
A 60-year-old man with Alzheimer's disease has been started on donepezil. What is the primary mechanism of action of this medication?
Which of the following is the most prominent clinical characteristic of Alzheimer's disease?
Which of the following is the most appropriate treatment for an overactive bladder in a patient with dementia?
True about dementia is:
A patient has a history of vomiting and was given an antiemetic. The patient subsequently developed abnormal movements (likely extrapyramidal symptoms or dystonia). What medication should be given to manage these abnormal movements?
Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
The use of levodopa is avoided in which of the following patients?
Which drug can cause psychosis?
Propranolol, a non-selective beta blocker, can be prescribed to decrease anxiety associated with which of the following conditions?
Which of the following is an atypical antidepressant?
Drugs for Dementia Indian Medical PG Practice Questions and MCQs
Question 1: A 60-year-old man with Alzheimer's disease has been started on donepezil. What is the primary mechanism of action of this medication?
- A. NMDA receptor antagonist
- B. Acetylcholinesterase inhibitor (Correct Answer)
- C. Dopamine receptor antagonist
- D. Serotonin reuptake inhibitor
Explanation: ***Acetylcholinesterase inhibitor*** - Donepezil **blocks the enzyme acetylcholinesterase**, which is responsible for breaking down acetylcholine [1], [2]. - By inhibiting this enzyme, donepezil **increases the levels of acetylcholine** in the brain, improving **cholinergic neurotransmission** in patients with Alzheimer's disease [2]. *NMDA receptor antagonist* - **NMDA receptor antagonists** like **memantine** work by blocking the activity of glutamate at the NMDA receptor, which is thought to reduce excitotoxicity in Alzheimer's [1], [3]. - This mechanism is different from donepezil, which targets the **cholinergic system** [1]. *Dopamine receptor antagonist* - **Dopamine receptor antagonists** are primarily used in conditions like **schizophrenia** or **Parkinson's disease** (for psychotic symptoms), by blocking dopamine receptors. - This is not the mechanism of action for medications used to treat cognitive symptoms of Alzheimer's disease. *Serotonin reuptake inhibitor* - **Serotonin reuptake inhibitors (SSRIs)** are a class of antidepressants that increase serotonin levels in the brain by blocking its reuptake [3]. - While depression can co-occur with Alzheimer's, SSRIs do not directly address the cognitive decline associated with the disease [3].
Question 2: Which of the following is the most prominent clinical characteristic of Alzheimer's disease?
- A. Memory loss (Correct Answer)
- B. Neurofibrillary tangles
- C. Amyloid plaques
- D. Resting tremor
Explanation: ***Memory loss*** - **Memory loss**, particularly of recent events (anterograde amnesia), is the **earliest and most prominent clinical symptom** of Alzheimer's disease. - This is a **clinical characteristic** - an observable symptom experienced by the patient and noted by clinicians during evaluation. - The memory deficit progressively worsens, initially affecting **short-term recall** and learned information, eventually extending to long-term memory and significantly impacting daily functioning. *Neurofibrillary tangles* - **Neurofibrillary tangles**, composed of hyperphosphorylated tau protein, are a **pathological hallmark** found in the brains of Alzheimer's patients at autopsy or biopsy. - These are **microscopic findings**, not a clinical characteristic - they cannot be observed directly by the patient or clinician during clinical evaluation. - Essential for definitive neuropathological diagnosis but not a clinical symptom. *Amyloid plaques* - **Amyloid plaques** (senile plaques), formed by aggregation of beta-amyloid peptides, are another **pathological hallmark** of Alzheimer's disease. - Like neurofibrillary tangles, these are **microscopic neuropathological findings**, not observable clinical symptoms. - They represent the underlying disease pathology but not the clinical presentation. *Resting tremor* - A **resting tremor** is a cardinal motor symptom of **Parkinson's disease**, not Alzheimer's disease. - While some patients with advanced Alzheimer's may develop motor symptoms, resting tremor is **not a characteristic or prominent feature** of Alzheimer's disease. - This option tests knowledge of differential diagnosis between neurodegenerative disorders.
Question 3: Which of the following is the most appropriate treatment for an overactive bladder in a patient with dementia?
- A. Tolterodine (Correct Answer)
- B. Mirabegron
- C. Behavioral therapy/bladder training
- D. Oxybutynin
- E. Trospium
Explanation: ***Tolterodine*** - **Tolterodine** is a **muscarinic antagonist** that blocks acetylcholine receptors in the bladder, reducing detrusor muscle contractions and overactive bladder symptoms. - Unlike some other anticholinergics like oxybutynin, it has a **lower propensity to cross the blood-brain barrier** and thus a reduced risk of exacerbating cognitive impairment in patients with dementia. *Mirabegron* - **Mirabegron** is a **beta-3 adrenergic agonist** that relaxes the detrusor muscle, increasing bladder capacity. - While it has a different mechanism of action and is less likely to cause anticholinergic cognitive side effects than older anticholinergics, it can still cause **hypertension** and **tachycardia**, which may be problematic in elderly patients with comorbidities. *Behavioral therapy/bladder training* - **Behavioral therapy** and **bladder training** are important first-line treatments for overactive bladder. - However, for patients with **dementia**, cognitive impairment often makes adherence to and understanding of these complex therapies challenging or impossible without significant caregiver support. *Oxybutynin* - **Oxybutynin** is an **anticholinergic drug** that is effective for overactive bladder. - However, it has a **high affinity for muscarinic receptors** in the brain and readily crosses the blood-brain barrier, significantly increasing the risk of **cognitive impairment, confusion, and delirium** in elderly patients, especially those with pre-existing dementia. *Trospium* - **Trospium** is a **quaternary amine anticholinergic** that is hydrophilic and has minimal blood-brain barrier penetration. - While theoretically safer than oxybutynin in terms of CNS effects, it has **lower bladder selectivity** compared to tolterodine and may cause more peripheral anticholinergic side effects (dry mouth, constipation).
Question 4: True about dementia is:
- A. Dementia due to atherosclerosis progresses in the same gradual manner as Alzheimer's disease
- B. Alzheimer's disease is due to multiple small strokes in the cerebral cortex
- C. Alzheimer's disease is associated with an increase in ACh release in the cerebral cortex
- D. Dementia involves a decline in memory and other cognitive functions affecting daily living (Correct Answer)
Explanation: ***Dementia involves a decline in memory and other cognitive functions affecting daily living*** - This statement accurately defines **dementia** as a significant decline in **cognitive functions**, including memory, language, problem-solving, and executive function, severe enough to interfere with daily activities. - The progressive nature of this decline leads to impaired independence and functional disability. *Dementia due to atherosclerosis progresses in the same gradual manner as Alzheimer's disease* - **Vascular dementia**, often caused by atherosclerosis leading to stroke or chronic cerebral ischemia, typically has a **stepped or fluctuating progression** rather than the gradual, continuous decline seen in Alzheimer's disease. - This is a key distinguishing feature between vascular dementia and Alzheimer's disease. *Alzheimer's disease is due to multiple small strokes in the cerebral cortex* - This describes **vascular dementia**, which is distinct from Alzheimer's disease. - **Alzheimer's disease** is characterized by the accumulation of **amyloid plaques** and **neurofibrillary tangles** in the brain, not by strokes. *Alzheimer's disease is associated with an increase in ACh release in the cerebral cortex* - **Alzheimer's disease** is associated with a significant **reduction in acetylcholine (ACh) levels** in the cerebral cortex, particularly in regions vital for memory and learning. - Many treatments for Alzheimer's aim to inhibit **acetylcholinesterase**, thereby increasing ACh availability to compensate for this deficit.
Question 5: A patient has a history of vomiting and was given an antiemetic. The patient subsequently developed abnormal movements (likely extrapyramidal symptoms or dystonia). What medication should be given to manage these abnormal movements?
- A. Hyoscine
- B. Methyl dopa
- C. Benzhexol (Correct Answer)
- D. Cyproheptadine
- E. Diphenhydramine
Explanation: ***Benzhexol*** - **Extrapyramidal symptoms (EPS)** and **dystonia** are often caused by dopamine receptor blockade, and **anticholinergic medications** like benzhexol help restore the **dopamine-acetylcholine balance**. - Benzhexol is a **muscarinic antagonist** that effectively reduces drug-induced Parkinsonism, dystonia, and akathisia by acting centrally. - It is the **preferred oral agent** for ongoing management of drug-induced movement disorders. *Diphenhydramine* - Diphenhydramine is an **antihistamine** with **anticholinergic properties** that can be used for **acute dystonic reactions**, particularly when given parenterally (IV/IM). - While effective for acute management, benzhexol is generally preferred for **ongoing oral therapy** and has more potent central anticholinergic effects. *Hyoscine* - While hyoscine is also an **anticholinergic agent**, it is primarily used for preventing **motion sickness** and managing **postoperative nausea and vomiting**. - Its efficacy in reversing acute extrapyramidal symptoms induced by neuroleptics or antiemetics is generally **less pronounced** compared to agents like benzhexol. *Methyl dopa* - Methyl dopa is an **alpha-2 adrenergic agonist** primarily used in the treatment of **hypertension**, especially in pregnancy. - It works by reducing sympathetic outflow and is **not indicated** for managing extrapyramidal symptoms or dystonia. *Cyproheptadine* - Cyproheptadine is an **antihistamine** with **serotonin antagonist** properties, used to treat allergic reactions, appetite stimulation, and occasionally **serotonin syndrome**. - It does not have significant anticholinergic effects that would alleviate medication-induced extrapyramidal symptoms or dystonia.
Question 6: Match the following drugs in Column A with their contraindications in Column B. | Column A | Column B | | :-- | :-- | | 1. Morphine | 1. QT prolongation | | 2. Amiodarone | 2. Thromboembolism | | 3. Vigabatrin | 3. Pregnancy | | 4. Estrogen preparations | 4. Head injury |
- A. A-1, B-3, C-2, D-4
- B. A-4, B-1, C-3, D-2 (Correct Answer)
- C. A-3, B-2, C-4, D-1
- D. A-2, B-4, C-1, D-3
Explanation: ***A-4, B-1, C-3, D-2*** - **Morphine** is contraindicated in **head injury** as it can increase intracranial pressure and mask neurological symptoms. - **Amiodarone** is contraindicated in patients with **QT prolongation** due to its risk of inducing more severe arrhythmias like Torsades de Pointes. - **Vigabatrin** is contraindicated during **pregnancy** due to its potential for teratogenicity and adverse effects on fetal development. - **Estrogen preparations** are contraindicated in patients with a history of **thromboembolism** due to their increased risk of blood clot formation. *A-1, B-3, C-2, D-4* - This option incorrectly matches **Morphine** with QT prolongation and **Estrogen preparations** with head injury, which are not their primary contraindications. - It also incorrectly links **Vigabatrin** with thromboembolism and **Amiodarone** with pregnancy. *A-3, B-2, C-4, D-1* - This choice incorrectly associates **Morphine** with pregnancy and **Vigabatrin** with head injury, which are not the most critical or direct contraindications. - It also misaligns **Amiodarone** with thromboembolism and **Estrogen preparations** with QT prolongation. *A-2, B-4, C-1, D-3* - This option incorrectly matches **Morphine** with thromboembolism and **Amiodarone** with head injury, which are not their most significant contraindications. - It also incorrectly links **Vigabatrin** with QT prolongation and **Estrogen preparations** with pregnancy.
Question 7: The use of levodopa is avoided in which of the following patients?
- A. Amyotrophic lateral sclerosis
- B. Psychosis (Correct Answer)
- C. Alzheimer's disease
- D. Essential tremor
Explanation: ***Psychosis*** - Levodopa increases **dopaminergic activity** in the brain, which can significantly worsen or induce **psychotic symptoms** like hallucinations and delusions. - Patients with pre-existing psychosis or a history of psychotic episodes are at high risk, making levodopa a **contraindicated** treatment. *Alzheimer's disease* - While Alzheimer's patients may experience motor symptoms, levodopa is generally not avoided unless there are specific **parkinsonian features** responsive to dopamine. - The primary symptoms of Alzheimer's are **cognitive decline**, which levodopa does not treat and could potentially worsen agitation or confusion in advanced stages. *Amyotrophic lateral sclerosis* - **ALS** is a progressive neurodegenerative disease affecting motor neurons, leading to muscle weakness and atrophy. - Levodopa is **not effective** in treating ALS because the disease pathology does not involve dopamine deficiency. *Essential tremor* - Essential tremor is a movement disorder primarily treated with **beta-blockers** or **anti-seizure medications**. - Levodopa has **no established efficacy** in treating essential tremor, and its use is unrelated to its pathophysiology.
Question 8: Which drug can cause psychosis?
- A. Ofloxacin
- B. Amfetamine (Correct Answer)
- C. Capreomycin
- D. Rifampicin
Explanation: ### Explanation **Correct Option: B. Amfetamine** Amfetamine is a potent CNS stimulant that acts primarily by increasing the release of biogenic amines, particularly **Dopamine**, from presynaptic nerve terminals. According to the **Dopamine Hypothesis of Schizophrenia**, excessive dopaminergic activity in the mesolimbic pathway is linked to psychotic symptoms. High doses or chronic use of amfetamines can induce a "stimulant psychosis" that clinically mimics paranoid schizophrenia, characterized by delusions, hallucinations, and stereotypic behavior. **Analysis of Incorrect Options:** * **A. Ofloxacin:** While fluoroquinolones can occasionally cause CNS side effects like insomnia or dizziness, they are not classically associated with inducing frank psychosis. * **C. Capreomycin:** This is a polypeptide protein synthesis inhibitor used in MDR-TB. Its primary toxicities are **nephrotoxicity** and **ototoxicity** (8th cranial nerve damage), similar to aminoglycosides. * **D. Rifampicin:** A key anti-tubercular drug known for causing orange-colored secretions (urine, sweat, tears) and hepatotoxicity. It does not have psychotropic side effects. **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing psychosis:** Levodopa (dopamine precursor), Steroids ("Steroid Psychosis"), Isoniazid (INH), Ketamine, and Cocaine. * **Drug of Choice for Amfetamine Psychosis:** Antipsychotics like **Haloperidol** (D2 blockers) are used to manage acute symptoms. * **Mechanism Recap:** Amfetamines reverse the direction of the dopamine transporter (DAT), pumping dopamine out into the synapse.
Question 9: Propranolol, a non-selective beta blocker, can be prescribed to decrease anxiety associated with which of the following conditions?
- A. Chronic neurotic disorder
- B. Schizophrenia
- C. Short-term stressful situations (Correct Answer)
- D. Endogenous depression
Explanation: **Explanation:** **1. Why Option C is Correct:** Propranolol is a non-selective beta-adrenergic blocker that acts by inhibiting the effects of catecholamines on $\beta_1$ and $\beta_2$ receptors. In anxiety, it does not treat the core psychological distress but effectively suppresses the **peripheral somatic symptoms** of sympathetic overactivity, such as palpitations, tremors, sweating, and tachycardia. This makes it highly effective for **short-term stressful situations** (Performance Anxiety), such as public speaking, stage performances, or examinations, where physical symptoms might impair performance. **2. Why Other Options are Incorrect:** * **A. Chronic Neurotic Disorder:** These conditions (like Generalized Anxiety Disorder) require long-term management of psychological symptoms. SSRIs or SNRIs are the first-line treatments; Propranolol is insufficient as a monotherapy for chronic psychological anxiety. * **B. Schizophrenia:** This is a psychotic disorder characterized by dopamine dysregulation. It is treated with antipsychotics (D2 blockers). While Propranolol may be used to treat antipsychotic-induced *Akathisia*, it has no role in treating the primary symptoms of Schizophrenia. * **D. Endogenous Depression:** This is a mood disorder involving serotonin and norepinephrine deficits. Beta-blockers are generally avoided here as they can occasionally worsen depressive symptoms (propranolol is lipophilic and crosses the BBB). **3. Clinical Pearls for NEET-PG:** * **Drug of Choice for Akathisia:** Propranolol is the first-line treatment for antipsychotic-induced akathisia (restlessness). * **Performance Anxiety:** It is specifically used for "Stage Fright." * **Contraindications:** Avoid in patients with **Asthma/COPD** (due to $\beta_2$ blockade causing bronchospasm) and **Diabetes Mellitus** (masks tachycardia, a warning sign of hypoglycemia). * **Lipid Solubility:** Propranolol is highly lipid-soluble, allowing it to cross the blood-brain barrier, which contributes to its central effects.
Question 10: Which of the following is an atypical antidepressant?
- A. Citalopram
- B. Sertraline
- C. Venlafaxine (Correct Answer)
- D. Reboxetine
Explanation: ### Explanation The classification of antidepressants is a high-yield topic for NEET-PG. Antidepressants are categorized based on their mechanism of action and chemical structure. **Correct Option: C. Venlafaxine** Venlafaxine is classified as a **Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)**. In many clinical classifications and competitive exams, SNRIs (like Venlafaxine and Duloxetine) and other newer classes (like Bupropion, Mirtazapine, and Trazodone) are grouped under the umbrella of **"Atypical Antidepressants"** because they differ from the traditional Tricyclic Antidepressants (TCAs) and Monoamine Oxidase Inhibitors (MAOIs) in both structure and side-effect profile. Venlafaxine inhibits the reuptake of both 5-HT and NE, making it effective for major depression and anxiety disorders. **Incorrect Options:** * **A & B (Citalopram and Sertraline):** These belong to the **Selective Serotonin Reuptake Inhibitors (SSRIs)** class. SSRIs are the first-line treatment for depression but are distinct from the "atypical" category. * **D (Reboxetine):** This is a **Selective Norepinephrine Reuptake Inhibitor (NRI)**. While it is a newer drug, it is specifically categorized by its selective action on norepinephrine rather than being grouped with the general atypical agents. **High-Yield Clinical Pearls for NEET-PG:** * **Venlafaxine:** At low doses, it acts primarily on serotonin; at higher doses (>150 mg), it significantly affects norepinephrine. A key side effect to monitor is **dose-dependent hypertension**. * **Duloxetine (SNRI):** Preferred in patients with comorbid **diabetic neuropathy** or chronic pain. * **Mirtazapine:** An $\alpha_2$-blocker (NaSSA) known for causing **weight gain and sedation**, making it useful for depressed patients with insomnia and anorexia. * **Bupropion:** Inhibits DA and NE reuptake; it is unique because it **does not cause sexual dysfunction** and is used for smoking cessation.
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