Central Nervous System Pharmacology Practice Questions

Q: Which drug is commonly used to mitigate the side effects of haloperidol?

Benztropine. ***Correct Option C: Benztropine*** - **Benztropine** is an **anticholinergic medication** commonly used to treat **extrapyramidal symptoms (EPS)** induced by antipsychotics like haloperidol - EPS, such as **dystonia**, **akathisia**, and **parkinsonism**, occur due to dopaminergic blockade in the nigrostriatal pathway - Benztropine works by blocking muscarinic receptors, helping to restore the dopamine-acetylcholine balance in the basal ganglia *Incorrect Option A: Clozapine* - **Clozapine** is an **atypical antipsychotic** known for its effectiveness in **treatment-resistant schizophrenia** and a lower risk of EPS compared to typical antipsychotics - However, it is not used to mitigate existing side effects of other antipsychotics due to its unique side effect profile, including agranulocytosis and myocarditis - Clozapine is a therapeutic alternative, not a treatment for EPS *Incorrect Option B: Imipramine* - **Imipramine** is a **tricyclic antidepressant (TCA)** primarily used to treat **depression** and **anxiety disorders** - It does not have properties that would mitigate the extrapyramidal side effects induced by antipsychotics - TCAs have anticholinergic properties but are not used for EPS management *Incorrect Option D: Haloperidol* - **Haloperidol** is a **typical antipsychotic** itself, and it is the drug whose side effects (e.g., EPS) are being mitigated - Administering more haloperidol would exacerbate, not mitigate, its side effects - This is the causative agent, not the treatment

Q: Antiviral drug amantadine is approved for treating which of the following conditions?

Parkinsonism. ***Parkinsonism*** - **Amantadine** is an **antiviral agent** that also has **anti-Parkinsonian effects**, particularly useful for treating **dyskinesias** associated with long-term levodopa therapy. - It acts by influencing **dopaminergic neurotransmission** and has **NMDA receptor antagonist** properties. *Schizophrenia* - Schizophrenia is primarily treated with **antipsychotic medications** that target **dopamine** and **serotonin receptors**. - **Amantadine** is not indicated for the treatment of psychosis or other symptoms of schizophrenia. *Depression* - Depression is typically managed with **antidepressants** that modulate **serotonin**, **norepinephrine**, or **dopamine** levels. - **Amantadine** does not have established efficacy as an antidepressant drug. *Alzheimer's disease* - Treatment for Alzheimer's disease often involves **cholinesterase inhibitors** and **NMDA receptor antagonists** like memantine for cognitive symptoms. - While amantadine is an NMDA receptor antagonist, it is **not approved** or commonly used for the primary treatment of Alzheimer's disease.

Q: The following symptoms may be seen in opium withdrawal:

Lacrimation. ***Lacrimation*** - Opioid withdrawal is characterized by **autonomic hyperactivity**, leading to symptoms like **lacrimation** (tearing), rhinorrhea (runny nose), and piloerection. - This is a rebound effect from the chronic opioid suppression of the parasympathetic nervous system. *Tremors* - While tremors can occur in various withdrawal syndromes, they are more characteristic of **alcohol** or **benzodiazepine withdrawal**, which involve GABAergic systems. - Opioid withdrawal can cause muscle aches and spasms, but **significant, sustained tremors** are not a primary diagnostic criterion. *Dry nose and mouth* - **Dry mouth** is a common side effect of opioid use, due to their anticholinergic effects, but during **withdrawal**, patients experience increased secretions like rhinorrhea and **lacrimation**. - **Dry nose** is also contrary to the typical presentation of opioid withdrawal, which involves a **runny nose**. *Constipation* - **Constipation** is a well-known side effect of chronic opioid use due to reduced gut motility. - During withdrawal, patients typically experience **diarrhea** and abdominal cramping, as gut motility returns and often becomes hyperactive.

Q: Which one of the following drugs is not a long-acting neuromuscular blocking agent?

Mivacurium. ***Mivacurium*** - Mivacurium is an **intermediate-duration neuromuscular blocking agent**, typically lasting 15-20 minutes. - Its short duration of action is due to its rapid hydrolysis by **plasma cholinesterase**. *Doxacurium* - Doxacurium is classified as a **long-acting neuromuscular blocking agent**, with effects lasting 90-120 minutes. - It works by competitively blocking the action of **acetylcholine** at the neuromuscular junction. *Pancuronium* - Pancuronium is a **long-acting neuromuscular blocking agent**, with a duration of action of 90-120 minutes. - It is known for its vagolytic effect, which can lead to **tachycardia**. *Pipecuronium* - Pipecuronium is a **long-acting neuromuscular blocking agent**, similar to pancuronium, with a duration of action around 90-120 minutes. - It is an aminosteroid derivative used to produce **skeletal muscle relaxation** during surgery or mechanical ventilation.

Q: Which of the following statements is FALSE regarding drugs in the treatment of Parkinsonism?

Amantadine is more effective than levodopa. ***Amantadine is more effective than levodopa*** - This statement is **false** because **levodopa** is considered the **gold standard** and most effective treatment for symptomatic Parkinsonism, especially for bradykinesia and rigidity [1, 2]. - While amantadine can be helpful for dyskinesias and offers modest symptomatic relief, its efficacy is significantly **less than levodopa** [1]. *Amantadine causes ankle edema* - This statement is **true**. **Amantadine** is known to cause **peripheral edema**, particularly in the ankles and feet, as a common side effect [1]. - This adverse effect can be managed by reducing the dose or discontinuing the drug if bothersome. *Levodopa is effective in reducing tremors* - This statement is **true**, though with an important caveat. **Levodopa** does reduce tremor in Parkinson's disease, but it is **less effective for tremor** compared to its dramatic effects on bradykinesia and rigidity [1]. - Among parkinsonian symptoms, **tremor responds least well to levodopa** and may require additional agents like anticholinergics or propranolol for optimal control. - Nevertheless, levodopa does provide tremor reduction in most patients, making this statement true overall. *Anti-muscarinic agents are effective in drug-induced Parkinsonism* - This statement is **true**. **Anticholinergic (anti-muscarinic) agents** like benztropine and trihexyphenidyl are often used to treat **drug-induced Parkinsonism**, particularly symptoms like tremor and dystonia [1, 2]. - This form of Parkinsonism is typically caused by dopamine receptor blocking drugs (antipsychotics), making anticholinergics effective by rebalancing cholinergic overactivity.

Q: Which of the following drugs is not effective in the treatment of trigeminal neuralgia?

Acetaminophen. ***Acetaminophen*** - **Acetaminophen** is a common **analgesic** and antipyretic but lacks the direct effect on neuronal hyperexcitability required for treating **neuropathic pain** conditions like trigeminal neuralgia. - Its mechanism of action primarily involves inhibiting prostaglandin synthesis peripherally and centrally, which is insufficient for managing the sharp, stabbing pain of **trigeminal neuralgia**. *Carbamazepine* - **Carbamazepine** is considered the **first-line treatment** for trigeminal neuralgia due to its efficacy in stabilizing hyperexcitable nerve membranes. - It works by blocking **voltage-gated sodium channels**, thereby reducing the firing of trigeminal nerve fibers. *Phenytoin sodium* - **Phenytoin** is an **antiepileptic drug** that can be used as a second-line or adjunctive treatment for trigeminal neuralgia. - Similar to carbamazepine, it acts by **inhibiting voltage-gated sodium channels**, thereby preventing repetitive firing of action potentials. *Baclofen* - **Baclofen** is a **GABA-B receptor agonist** that can be used in combination with carbamazepine or as an alternative for patients who do not respond to or tolerate carbamazepine. - It helps reduce the intensity and frequency of pain by **inhibiting excitatory neurotransmitter release** in the brainstem trigeminal nucleus.

Q: Which of the following drugs is the most commonly prescribed first-line treatment for Alzheimer's disease?

Donepezil. ***Donepezil*** - **Donepezil** is a **centrally acting, reversible acetylcholinesterase inhibitor** and is widely considered the **first-line treatment** for mild to moderate Alzheimer's disease due to its efficacy and once-daily dosing. - It works by increasing the concentration of **acetylcholine** in the synaptic cleft, thereby enhancing cholinergic transmission in the brain. *Rivastigmine* - **Rivastigmine** is also an **acetylcholinesterase inhibitor**, available in oral and transdermal patch formulations, and is used for mild to moderate Alzheimer's. - While effective, it is often considered a **second-line** or alternative agent due to potential for more gastrointestinal side effects compared to donepezil. *Galantamine* - **Galantamine** is another **acetylcholinesterase inhibitor** with an additional mechanism of action as an **allosteric potentiator of nicotinic acetylcholine receptors**. - It is effective in mild to moderate Alzheimer's but is not typically the very first choice given the established prevalence and convenience of donepezil. *Memantine* - **Memantine** is an **NMDA receptor antagonist** and works by blocking the effects of excessive **glutamate**, which is thought to contribute to neurodegeneration in Alzheimer's. - It is generally prescribed for **moderate to severe Alzheimer's disease** and is not considered a first-line treatment for early stages.

Q: All 5-HT receptors are heptahelical serpentine receptors EXCEPT:

5-HT3. ***5-HT3*** - The **5-HT3 receptor** is unique among serotonin receptors because it is a **ligand-gated ion channel**, not a G protein-coupled receptor [2]. - Its activation directly results in rapid depolarization due to the influx of **sodium ions**, unlike the slower, second-messenger mediated responses of other 5-HT receptors [2].*5-HT1* - The **5-HT1 receptor** family (1A, 1B, 1D, 1E, 1F) are all **heptahelical G protein-coupled receptors** [1, 2]. - They are primarily coupled to **inhibitory G proteins (Gi/Go)**, leading to a decrease in cAMP levels.*5-HT4* - The **5-HT4 receptor** is a **heptahelical G protein-coupled receptor** [1, 2]. - It is coupled to **stimulatory G proteins (Gs)**, leading to an increase in cAMP levels.*5-HT2* - The **5-HT2 receptor** family (2A, 2B, 2C) are all **heptahelical G protein-coupled receptors** [1, 2]. - They are predominantly coupled to **Gq proteins**, leading to the activation of phospholipase C and increased intracellular calcium.

Q: Which of the following is a short-acting benzodiazepine?

Midazolam. ***Midazolam*** - **Midazolam** is a **short-acting benzodiazepine** with a rapid onset and short duration of action, mainly due to its high lipid solubility and rapid metabolism. - It is often used for **premedication**, **sedation** for procedures, and induction of **anesthesia**. *Lorazepam* - **Lorazepam** is an **intermediate-acting benzodiazepine** with a half-life of 10-20 hours. - It is commonly used for **anxiety**, **insomnia**, and *status epilepticus*, but its duration of action is longer than truly short-acting agents. *Diazepam* - **Diazepam** is a **long-acting benzodiazepine** with a half-life ranging from 20 to 100 hours, largely due to its active metabolites, such as **nordiazepam**. - It is used for conditions requiring sustained effects, such as **chronic anxiety**, **muscle spasms**, and **alcohol withdrawal**. *Temazepam* - **Temazepam** is an **intermediate-acting benzodiazepine** with a half-life of 8-20 hours. - It is primarily prescribed for **insomnia** due to its relatively quick onset and moderate duration of action, which is not as short as midazolam.

Q: Which of the following drugs can be used as a transdermal patch for the treatment of Parkinson's disease?

Rotigotine. ***Rotigotine*** - **Rotigotine** is a **dopamine agonist** that is formulated as a **transdermal patch** for continuous delivery, improving compliance and reducing "off" times in Parkinson's disease. - The patch provides steady drug levels, minimizing motor fluctuations often seen with oral medications. *Levodopa* - Levodopa is the **most effective drug** for Parkinson's, but it's administered **orally** and has a short half-life, requiring frequent dosing. - While it can be combined with carbidopa/benserazide to prevent peripheral conversion, it is not available as a transdermal patch. *Apomorphine* - Apomorphine is a **potent dopamine agonist** used for rapid relief of "off" episodes; however, it is administered via **subcutaneous injection**. - It is not available in a transdermal patch formulation due to its chemical characteristics and rapid action. *Selegiline* - **Selegiline** is a **MAO-B inhibitor** that slows the breakdown of dopamine and is used as an adjunct in Parkinson's, and is available in **oral** and **sublingual forms**. - While it has transdermal formulations for depression (e.g., Emsam), it is not used as a patch for Parkinson's disease treatment.

Question 1

Which drug is commonly used to mitigate the side effects of haloperidol?

Accepted Answer

Benztropine

Answer

Clozapine

Answer

Imipramine

Answer

Haloperidol

Question 2

Antiviral drug amantadine is approved for treating which of the following conditions?

Accepted Answer

Parkinsonism

Answer

Depression

Answer

Alzheimer's disease

Answer

Schizophrenia

Question 3

The following symptoms may be seen in opium withdrawal:

Accepted Answer

Lacrimation

Answer

Tremors

Answer

Constipation

Answer

Dry nose and mouth

Question 4

Which one of the following drugs is not a long-acting neuromuscular blocking agent?

Accepted Answer

Mivacurium

Answer

Pancuronium

Answer

Doxacurium

Answer

Pipecuronium

Question 5

Which of the following statements is FALSE regarding drugs in the treatment of Parkinsonism?

Accepted Answer

Amantadine is more effective than levodopa

Answer

Levodopa is effective in reducing tremors

Answer

Amantadine causes ankle edema

Answer

Anti-muscarinic agents are effective in drug-induced Parkinsonism

Question 6

Which of the following drugs is not effective in the treatment of trigeminal neuralgia?

Accepted Answer

Acetaminophen

Answer

Phenytoin sodium

Answer

Carbamazepine

Answer

Baclofen

Question 7

Which of the following drugs is the most commonly prescribed first-line treatment for Alzheimer's disease?

Accepted Answer

Donepezil

Answer

Rivastigmine

Answer

Galantamine

Answer

Memantine

Question 8

All 5-HT receptors are heptahelical serpentine receptors EXCEPT:

Accepted Answer

5-HT3

Answer

5-HT1

Answer

5-HT4

Answer

5-HT2

Question 9

Which of the following is a short-acting benzodiazepine?

Accepted Answer

Midazolam

Answer

Lorazepam

Answer

Diazepam

Answer

Temazepam

Question 10

Which of the following drugs can be used as a transdermal patch for the treatment of Parkinson's disease?

Accepted Answer

Rotigotine

Answer

Apomorphine

Answer

Levodopa

Answer

Selegiline

Central Nervous System Pharmacology — MCQs

Central Nervous System Pharmacology — MCQs

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