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How long does it take carbidopa levodopa to work?

Medically reviewed by Sally Chao, MD. Last updated on Sep 23, 2024.

Official answer

by Drugs.com

The short-acting (immediate-release) formulation of carbidopa/levodopa takes effect within about 20 to 50 minutes. The long-acting (extended-release) formulation starts to work closer to the 50-minute timeframe.

When switching away from a short-acting formulation, the first dose of a long-acting formulation may take 1 hour longer than the immediate-release to take effect.

The combination of carbidopa and levodopa can also be delivered directly to the stomach via a tube. This method typically involves an initial dose given over 10 to 30 minutes, followed by a continuous dose over 16 hours. The effect is strongest after 2.5 hours of the 16-hour infusion.

Eating lots of protein or acidic foods may delay the onset of these medications when consumed close together. You may need to take carbidopa/levodopa 1 to 2 hours before a meal and plan mealtimes to avoid overlap between doses and eating.

The duration of effect is longer for the extended-release formulation of carbidopa/levodopa than for the immediate-release formulation. The effects of extended-release carbidopa/levodopa should last between 4 to 6 hours. The effects of immediate-release carbidopa/levodopa last for approximately 2 to 3 hours less time — about 2 to 3 hours in total.

References
  1. Mao Z, Hsu A, Gupta S, Modi NB. Population pharmacodynamics of IPX066: an oral extended-release capsule formulation of carbidopa-levodopa, and immediate-release carbidopa-levodopa in patients with advanced Parkinson's disease. J Clin Pharmacol. 2013;53(5):523-531. https://doi.org/10.1002/jcph.63.
  2. Hauser RA, Ellenbogen A, Khanna S, Gupta S, Modi NB. Onset and duration of effect of extended-release carbidopa-levodopa in advanced Parkinson's disease. Neuropsychiatr Dis Treat. 2018;14:839-845. Published 2018 Mar 22. https://doi.org/10.2147/NDT.S153321.
  3. U.S. Food and Drug Administration (FDA). SINEMET CR (CARBIDOPA-LEVODOPA) SUSTAINED-RELEASE TABLETS. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/019856s025lbl.pdf. [Accessed September 24, 2021].
  4. U.S. Food and Drug Administration (FDA). DUOPA (carbidopa and levodopa) enteral suspension. Last reviewed January 2015. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2015/203952s000lbl.pdf. [Accessed September 24, 2021].
  5. U.S. National Library of Medicine MedlinePlus. Levodopa and Carbidopa. Last reviewed June 15, 2018. Available at: https://medlineplus.gov/druginfo/meds/a601068.html. [Accessed September 24, 2021].

Read next

How often should carbidopa/levodopa be taken?

The immediate-release (short-acting) form of carbidopa/levodopa is usually taken 3 or 4 times each day, while the extended-release (long-acting) form is typically taken 2 to 4 times each day. Continue reading

Can carbidopa/levodopa cause high blood pressure?

Carbidopa/levodopa is unlikely to cause high blood pressure (hypertension). It was reported in less than 1% of patients in clinical trials and is not considered a common adverse reaction related to the drug. Continue reading

How does levodopa help Parkinson's disease?

Levodopa is a central nervous system agent that helps people with Parkinson’s because it is converted into dopamine in the brain. It helps to alleviate the symptoms of the disease by providing a supply of dopamine, which is lacking in people with Parkinson's.

Levodopa works best to help treat the slowness and stiffness or rigidity associated with Parkinson’s disease, and in some cases may treat the tremor as well. It does not slow or reduce the progression of Parkinson’s disease. Continue reading

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