Parkinson’s disease: pharmacotherapy and symptom management MCQs With Answer

This quiz collection on Parkinson’s disease pharmacotherapy and symptom management is tailored for M.Pharm students preparing for Pharmacotherapeutics II (MPP 202T). It contains 20 carefully crafted multiple-choice questions that probe mechanisms of action, pharmacokinetics, clinical applications, adverse effects, drug interactions, and advanced therapeutic options such as COMT inhibitors, MAO‑B inhibitors, dopamine agonists, levodopa formulations, device‑aided therapies and management of complications like wearing‑off and dyskinesia. Each question includes four options and the correct answer to support focused revision, deepen conceptual understanding, and strengthen exam‑level reasoning for complex clinical scenarios in Parkinson’s disease care.

Q1. What is the primary pharmacological purpose of combining carbidopa with levodopa in Parkinson’s disease therapy?

• To prevent peripheral conversion of levodopa to dopamine, increasing CNS availability
• To increase peripheral dopamine levels to reduce rigidity
• To inhibit monoamine oxidase in the brain
• To enhance renal excretion of levodopa

Correct Answer: To prevent peripheral conversion of levodopa to dopamine, increasing CNS availability

Q2. Which catechol‑O‑methyltransferase (COMT) inhibitor crosses the blood–brain barrier and has been associated with hepatotoxicity, requiring liver function monitoring?

• Tolcapone
• Entacapone
• Carbidopa
• Selegiline

Correct Answer: Tolcapone

Q3. Which dopamine agonist has relatively high D3 receptor affinity and is notably associated with impulse control disorders (e.g., pathological gambling)?

• Pramipexole
• Levodopa
• Entacapone
• Trihexyphenidyl

Correct Answer: Pramipexole

Q4. In a patient experiencing end‑of‑dose “wearing‑off” despite optimized levodopa dosing, which of the following is a commonly used adjunct to extend levodopa effect?

• Entacapone (COMT inhibitor)
• Metoclopramide
• Haloperidol
• Propranolol

Correct Answer: Entacapone (COMT inhibitor)

Q5. Which therapeutic strategy is most appropriate for management of severe, unpredictable on‑off fluctuations in advanced Parkinson’s disease?

• Continuous dopaminergic stimulation such as apomorphine infusion or levodopa‑carbidopa intestinal gel (LCIG)
• High‑dose typical antipsychotics
• Long‑term metoclopramide therapy
• Routine benzodiazepine use

Correct Answer: Continuous dopaminergic stimulation such as apomorphine infusion or levodopa‑carbidopa intestinal gel (LCIG)

Q6. Why does a high‑protein meal often reduce levodopa effectiveness?

• Dietary amino acids compete with levodopa for intestinal absorption and transport across the blood–brain barrier via large neutral amino acid transporters
• Protein increases renal clearance of levodopa
• Protein enhances peripheral decarboxylation of levodopa through vitamin K activation
• Protein binds levodopa in plasma forming inactive complexes

Correct Answer: Dietary amino acids compete with levodopa for intestinal absorption and transport across the blood–brain barrier via large neutral amino acid transporters

Q7. Which anticholinergic agent is most often used for tremor‑predominant Parkinson’s disease in younger patients?

• Trihexyphenidyl (benzhexol)
• Selegiline
• Entacapone
• Ropinirole

Correct Answer: Trihexyphenidyl (benzhexol)

Q8. Amantadine can be used in Parkinson’s disease primarily to:

• Reduce levodopa‑induced dyskinesia through NMDA receptor antagonism and modest dopamine release
• Inhibit peripheral aromatic L‑amino acid decarboxylase
• Block COMT centrally
• Act as a strong anticholinergic to control tremor

Correct Answer: Reduce levodopa‑induced dyskinesia through NMDA receptor antagonism and modest dopamine release

Q9. Co‑administration of a selective MAO‑B inhibitor with which class of drugs poses a significant risk of serotonin syndrome?

• SSRIs and other serotonergic antidepressants
• COMT inhibitors
• Anticholinergics
• Peripheral decarboxylase inhibitors

Correct Answer: SSRIs and other serotonergic antidepressants

Q10. Which antipsychotic is preferred for treating psychosis in Parkinson’s disease due to minimal D2 blockade at low doses and relatively preserved motor function?

• Clozapine (low dose with monitoring)
• Haloperidol
• Risperidone
• Metoclopramide

Correct Answer: Clozapine (low dose with monitoring)

Q11. Drug‑induced parkinsonism from typical antipsychotics primarily results from blockade of which receptor in the nigrostriatal pathway?

• Dopamine D2 receptors
• Muscarinic M1 receptors
• Serotonin 5‑HT1A receptors
• Alpha‑1 adrenergic receptors

Correct Answer: Dopamine D2 receptors

Q12. Prior to initiating tolcapone therapy, which safety consideration is essential?

• Baseline and periodic liver function tests due to risk of hepatotoxicity
• Baseline ECG for QT prolongation only
• No monitoring is required for tolcapone
• Routine platelet counts to monitor agranulocytosis

Correct Answer: Baseline and periodic liver function tests due to risk of hepatotoxicity

Q13. Which advanced therapy delivers levodopa continuously into the small intestine to reduce motor fluctuations and dyskinesia?

• Levodopa‑carbidopa intestinal gel (LCIG)
• Oral controlled‑release levodopa tablet once daily
• Intravenous levodopa bolus therapy
• Subcutaneous haloperidol infusion

Correct Answer: Levodopa‑carbidopa intestinal gel (LCIG)

Q14. Which adverse effect is particularly characteristic of dopamine agonists and requires patient counseling and monitoring?

• Impulse control disorders such as pathological gambling and hypersexuality
• Severe hepatotoxicity in all patients
• Immediate agranulocytosis in most patients
• Persistent cough

Correct Answer: Impulse control disorders such as pathological gambling and hypersexuality

Q15. Which enzyme is responsible for converting levodopa into dopamine in the periphery and centrally?

• Aromatic L‑amino acid decarboxylase (DOPA decarboxylase)
• Monoamine oxidase B (MAO‑B)
• Catechol‑O‑methyltransferase (COMT)
• Tyrosine hydroxylase

Correct Answer: Aromatic L‑amino acid decarboxylase (DOPA decarboxylase)

Q16. Why does carbidopa not significantly inhibit central decarboxylation of levodopa?

• Carbidopa is a polar compound that does not cross the blood–brain barrier effectively
• Carbidopa selectively binds to peripheral COMT enzymes only
• Carbidopa is rapidly metabolized before reaching the brain
• Carbidopa is an MAO inhibitor rather than a decarboxylase inhibitor

Correct Answer: Carbidopa is a polar compound that does not cross the blood–brain barrier effectively

Q17. Which agent is most commonly used to reduce levodopa‑induced peak‑dose dyskinesias?

• Amantadine
• Entacapone
• Metoclopramide
• Haloperidol

Correct Answer: Amantadine

Q18. Which commonly prescribed antiemetic should be avoided in Parkinson’s disease because it can worsen parkinsonian symptoms by dopamine receptor antagonism?

• Metoclopramide
• Ondansetron
• Domperidone (peripheral D2 antagonist not crossing BBB)
• Prochlorperazine at very low doses only

Correct Answer: Metoclopramide

Q19. Deep brain stimulation (DBS) targeting which structure often allows substantial reduction of dopaminergic medications while improving motor fluctuations?

• Subthalamic nucleus (STN)
• Ventral tegmental area (VTA)
• Cerebellar deep nucleus
• Frontal cortex

Correct Answer: Subthalamic nucleus (STN)

Q20. How does pyridoxine (vitamin B6) affect levodopa therapy when levodopa is administered without a peripheral decarboxylase inhibitor?

• Pyridoxine enhances peripheral decarboxylation of levodopa, reducing central availability and clinical response
• Pyridoxine inhibits renal elimination of levodopa improving response
• Pyridoxine directly increases dopamine receptor sensitivity in the brain
• Pyridoxine acts as a COMT inhibitor increasing levodopa half‑life

Correct Answer: Pyridoxine enhances peripheral decarboxylation of levodopa, reducing central availability and clinical response

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