A 55-year-old man with Parkinson's disease on levodopa-carbidopa develops troublesome wearing-off and peak-dose dyskinesias. Adjusting the levodopa timing has not helped. Which pharmacological strategy specifically targets wearing-off by inhibiting peripheral COMT enzyme?
- A Rasagiline
- B Amantadine
- C Entacapone ✓
- D Pramipexole
Explanation
Entacapone is a peripheral (and to some degree central) catechol-O-methyltransferase (COMT) inhibitor that reduces the peripheral breakdown of levodopa, prolonging its plasma half-life and reducing wearing-off fluctuations. It is given with each levodopa dose. Tolcapone is a more potent COMT inhibitor with both peripheral and central activity but requires liver function monitoring. Rasagiline is a MAO-B inhibitor that also reduces wearing-off. Amantadine reduces peak-dose dyskinesias by NMDA receptor antagonism. Pramipexole is a dopamine agonist used to smooth motor fluctuations.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.