Carbidopa/levodopa

What are the facts?What are the Facts?

  • Levodopa was developed in the late 1960s and was the first medication proven effective in treating a chronic neurodegenerative disease like PD.
  • Levodopa in pill form is absorbed in the blood from the small intestine and travels through the blood to the brain, where it is converted into dopamine.
  • Once the brain converts levodopa into dopamine, it is stored in the neurons until needed by the body for movement.
  • Levodopa remains the single most effective agent in the management of Parkinson’s symptoms.
  • Levodopa is almost always given in combination with another medication called Carbidopa. Carbidopa is also a levodopa enhancer. When added, carbidopa enables a much lower dose of levodopa (80% less!) and helps reduce the side effects of nausea and vomiting.
  • Carbidopa/levodopa tablets are available in immediate-release and slow-release forms as well as dissolvable tablets that are placed under the tongue.
  • Carbidopa/levodopa extended release (ER) capsules (Rytary™) maintain levodopa concentrations longer than the immediate-release or other available oral levodopa formulations. Following an initial peak at about one hour, plasma levodopa concentrations are maintained for about 4 to 5 hours before declining. Clinical trials indicate that patients with motor fluctuations on other oral carbidopa/levodopa products may be able to switch to carbidopa/levodopa ER and experience a reduction in “off” time while requiring fewer medication administrations. Carbidopa/levodopa ER can be taken with or without food, but high fat meals may delay absorption. Dosages of carbidopa/levodopa ER are not interchangeable with dosages other carbidopa-levodopa products.

Did you know?
Forty years after it was first introduced, levodopa is still the most effective medication available for the treatment of the motor symptoms

What are the Common Side Effects?

  • Nausea
  • Vomiting
  • Loss of appetite
  • Lightheadedness
  • Lowered blood pressure
  • Confusion
  • Dyskinesia (if used as a long-term therapy; between 3-5 years)
    • People who use levodopa longterm may experience dyskinesia at some point, usually three to five years after starting the medication.
    • The term dyskinesia describes involuntary, erratic, writhing movements of the face, arms, legs, and/or trunk, which usually occur one to two hours after a dose of levodopa has been absorbed into the bloodstream and is having its peak clinical effect.
  • Uncommon side effects
    • Sleepiness, sudden onset sleep
    • Impulse control disorders (compulsive behaviors) such as excessive gambling, shopping, internet use or increased sexual behavior

Eating Proteins with Levodopa/Sinemet*

  • It is best to take Sinemet 30 to 60 minutes before eating a meal. This allows the Sinemet to be quickly absorbed before the food can interfere.
  • Take the Sinemet along with foods that don’t contain proteins.
  • Ginger tea is a good choice for many people, because it often “settles the stomach”.
  • A graham cracker or soda cracker along with the ginger tea may help too.
  • These foods are very low in protein and should not interfere with the absorption of Sinemet.

*Some countries are experiencing a Sinemet shortage; however, the shortage is not expected to affect the United States.

Caution: PD medications may have interactions with certain foods, other medications, vitamins, herbal supplements, over the counter cold pills and other remedies.  Anyone taking a PD medication should talk to their doctor and pharmacist about potential drug interactions.

For more information relating to prescribing Rytary™, please see How to Dose Rytary (Carbidopa and Levodopa extended release), by Dr. Robert A. Hauser of the University of South Florida, an NPF Center of Excellence.

Want to Learn More?

Read this "Parkinson Report" article:
What's Hot: Sinemet is a Safe First Choice Therapy

Request a free copy of this NPF manual:
Medications

Watch this video:
When should medications be adjusted?

Medical content reviewed by: Nina Browner, MD—Medical Director of the NPF Center of Excellence at the University of North Carolina at Chapel Hill in North Carolina and by Fernando Pagan, MD—Medical Director of the NPF Center of Excellence at Georgetown University Hospital in Washington, D.C.

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