Which antiparkinsonian drug acts primarily by noncompetitive NMDA receptor antagonism and is specifically useful for reducing levodopa-induced dyskinesias?
- A Ropinirole
- B Entacapone
- C Amantadine ✓
- D Selegiline
Correct answer: C. Amantadine
Explanation
Amantadine antagonizes glutamate transmission through NMDA receptors and is the main oral agent with proven antidyskinetic effect in advanced Parkinson disease. Ropinirole is a dopamine agonist acting on D2 receptors, entacapone peripherally inhibits catechol-O-methyltransferase, and selegiline irreversibly inhibits monoamine oxidase B. None of these three targets the glutamatergic pathway driving peak-dose dyskinesias.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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