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Parkinson wearing off — USMLE Step 3 MCQ

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HardInternal Medicine (Chronic Management)Parkinson wearing offUSMLE Step 3

A 68-year-old man with Parkinson disease takes carbidopa-levodopa five times daily and has predictable end-of-dose off periods. He has repeatedly missed midday adjunct doses. After discussing alternatives, he chooses once-daily catechol-O-methyltransferase inhibition. He has stable Child-Pugh class B hepatic impairment. Which prescription is appropriate?

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Correct answer: B — Use opicapone 25 mg nightly, avoiding food for 1 hour before and after

The best answer is “Use opicapone 25 mg nightly, avoiding food for 1 hour before and after”. Opicapone provides once-daily COMT inhibition for levodopa-associated off episodes. The usual 50-mg bedtime dose is reduced to 25 mg in moderate hepatic impairment, and food is avoided for 1 hour before and after administration. Entacapone is administered with individual levodopa doses, while tolcapone is not a once-nightly drug and carries important hepatotoxicity precautions. Opicapone is an adjunct to carbidopa-levodopa for off episodes; moderate hepatic impairment requires 25 mg once daily at bedtime, with no food for 1 hour before or after the dose.

Reference: FDA: Ongentys Prescribing Information: https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/212489s000lbl.pdf