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How long does Rytary stay in your system?

Medically reviewed by Melisa Puckey, BPharm. Last updated on Feb 7, 2023.

Official answer


Rytary (carbidopa-levodopa) is an extended release capsule that works for 4 to 5 hours for Parkinson's symptoms.
Inside the capsule are microbeads of carbidopa-levodopa that dissolve at different rates, ⅓ of the beads dissolve fast and ⅔ of the beads dissolve slowly. This means that when you take the capsule it starts to work quickly and works for a longer time.

Why is a longer acting carbidopa-levodopa better for Parkinson's symptoms?

Carbidopa with levodopa often works well to control Parkinson’s symptoms when patients first start taking it, however:

  • After time patients may have “off” time in the gap between doses when Parkinson’s symptoms come back.
  • These ”‘off” times are when the medicine levels in the blood are lower.
  • By having a medicine that stays in the body for longer means that there is more “on” time and less “off” time and Parkinson's symptoms are better.
  • Rytary is an extended release capsule that lasts longer than a controlled release tablet and keeps the level of medicine high and steady so that patients' Parkinson's symptoms are improved as they have more “on” times and less “off” time.

Does food change how long Rytary works?

Yes, if you have a meal that is high in fat and calories it may delay Rytary being absorbed by up to 2 hours, when compared to it you take it on an empty stomach. This means its effect will be delayed by up to 2 hours.
If you have a high protein meal then the absorption of levodopa may be decreased.

Bottom line:

  • Contains carbidopa-levodopa which is used to treat Parkinson's symptoms
  • Is an extended release formulation that works quickly and for longer (4 to 5 hours).
  • Works more effectively at treating Parkinson's symptoms as there is more “on” time and less “off” time


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