Duopa (carbidopa/levodopa) is a brand-name drug prescribed for motor fluctuations of advanced Parkinson’s disease in adults. Duopa comes as a liquid suspension. It’s delivered daily, over time, into the small intestine by a portable pump.

Duopa is approved by the Food and Drug Administration (FDA) to treat motor fluctuations in people with advanced Parkinson’s disease (PD). Motor fluctuations are changes in your ability to move smoothly (without stiffness or shaking). Fluctuation is caused by several factors, including inconsistent levels of dopamine (a brain chemical that helps control movement).

Duopa combines two active ingredients: carbidopa and levodopa. Carbidopa belongs to a drug class called decarboxylase inhibitors (blockers). Levodopa belongs to a drug class called dopamine precursors. Duopa isn’t available in a generic version.

Keep reading for specific information about the dosage of Duopa, including its strength and how to use the medication. For a comprehensive look at Duopa, see this article.

Note: This article describes typical dosages for Duopa provided by the drug’s manufacturer. When using Duopa, always follow the instructions of your doctor. They’ll prescribe the Duopa dosage that’s right for you.

Below is information about Duopa’s form, strength, and dosage.

Duopa form

Duopa comes as a liquid suspension inside a cassette (a small container). The cassette connects to a portable pump that you’ll wear. The pump delivers the medication directly into your small intestine as an infusion. An infusion involves a liquid drug being given over time.

To use the pump-delivery system, you’ll need to have a medical procedure. See the “How Duopa is administered” section for details.

Duopa strength

Duopa comes in one strength. Each milliliter (mL) of liquid has 4.63 milligrams (mg) of carbidopa with 20 mg of levodopa.

One cassette holds about 100 mL of the liquid suspension, which is about 463 mg carbidopa/2,000 mg levodopa.

Typical dosages

There isn’t a typical range for Duopa dosing. Rather, it’s unique to each person. Dosing may be based on factors such as your dose of oral levodopa and the severity of your condition.

Before you start Duopa, your doctor will likely switch any levodopa you take to immediate-release carbidopa/levodopa oral tablets, such as Sinemet. (With immediate release, the drug releases into your body quickly.) This switch helps the doctor calculate your dosage of Duopa.

Be sure to follow the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Dosage for PD

Doctors may prescribe Duopa to help manage motor fluctuations in people with advanced PD.

If your doctor prescribes Duopa, they’ll calculate your dosage and program your pump. Duopa’s daily dosage consists of these three doses:

  • Morning dose: given first
  • Continuous dose: given throughout the day
  • Extra dose: given as needed based on your prescribed instructions

Typically, you’ll stay with your calculated daily dosage on the first day of treatment. Then your doctor will adjust your dosage depending on how your body responds to the drug. It may take several days of adjustments to reach a stable dosage that’s right for you. Your doctor will give you more details about this when they prescribe Duopa.

Your daily dosage of Duopa is delivered by the pump, typically over 16 hours. Duopa’s maximum recommended daily dosage is one cassette per 16-hour period. This amounts to about 463 mg of carbidopa and 2,000 mg levodopa.

For more information about your specific dosage, talk with your doctor.

Long-term treatment

Duopa is meant to be a long-term treatment. If you and your doctor determine that Duopa is safe and effective for you, you’ll likely use it long term. Your doctor will discuss your treatment plan with you before you start using Duopa.

The Duopa dosage your doctor prescribes will depend on several factors, including:

  • your age
  • your current dosage of oral levodopa
  • the severity of your condition
  • how your body responds to Duopa
  • side effects you may have with Duopa
  • other medical conditions you have

Dosage adjustments

Be sure to inform your doctor of all your medications and health conditions before using Duopa. For example, high protein diets, changes to diet, and certain drugs or supplements can alter Duopa’s effect and may require dosage or timing changes. To learn what drugs may interact with Duopa, see the “Interactions” section of this article.

Your doctor may need to make dosage adjustments based on how active you are.

They may also change your dosage if you develop fainting, low blood pressure, or sudden sleepiness. Tell your doctor right away if you have more serious concerns during Duopa treatment, such as:

Note: If you have thoughts of suicide, call 911 or your local emergency number. In the United States, you can also call or text the Suicide and Crisis Lifeline at 988 or text HOME to the Crisis Textline at 741741. You can also refer to this article for ways to seek support.

Duopa is a liquid drug that’s pumped through a tube into your small intestine. To use Duopa, you’ll need a medical procedure called a gastrostomy (commonly called a stomach tube placement). With this procedure, a surgeon will make a small hole in your abdomen to place a tube. The tube allows Duopa to directly reach your small intestine.

To know if Duopa is right for you, your doctor may first give Duopa through a tube in your nose. If your doctor recommends this, it will occur before the stomach tube procedure.

After you’ve healed from your tube placement procedure, you’ll be ready to use the Duopa pump. Your doctor or another healthcare professional will show you or your caregiver how to use it the first time. The delivery of the full daily dose takes about 16 hours. Usually, people attach the pump in the morning and detach it in the evening. Always use Duopa by following the instructions your doctor gives you.

You’ll store Duopa cassettes in the refrigerator, in the original carton. Before connecting it to the pump, let the cassette sit at room temperature for 20 minutes. For more information on Duopa’s storage, see the “Expiration” section in this article.

If you have questions about how to use Duopa, talk with your doctor or pharmacist. There’s also step-by-step instructions in Duopa’s prescribing information.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

Duopa is meant to be used as a daily treatment. If you don’t (or can’t) take it as scheduled, call your doctor. You may need to take your carbidopa/levodopa oral tablets as a substitute. Your doctor will tell you the correct dose and schedule for your tablets.

To help make sure you don’t miss your dose, try using a medication reminder. This can include setting an alarm on your clock or downloading a reminder app on your phone. You can also write a note somewhere visible, such as on your kitchen table.

Duopa overdose can be serious. Do not use more Duopa than your doctor prescribes. Taking more than the recommended amount can lead to increased side effects or overdose.

If you take more than the recommended amount of Duopa

Call your doctor right away if you believe you’ve taken too much Duopa. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

It’s recommended to never abruptly stop Duopa. If you’re considering stopping treatment with Duopa, talk with your doctor first. To safely discontinue Duopa, your doctor will slowly lower your dosage over time. This gradual decrease helps reduce your risk of withdrawal symptoms when you stop Duopa. (Withdrawal symptoms are side effects that happen after you stop taking a drug that your body is used to.)

A rapid dosage decrease can cause serious symptoms, including:

Tell your doctor immediately if you have any of these symptoms, as some may be life threatening.

Do not stop taking Duopa unless your doctor specifically tells you to do so. If you have questions about your PD treatment, talk with your doctor.

Some frequently asked questions about Duopa are listed below.

Is the dosage of Duopa similar to the dosage of Sinemet?

It is related but not the same. Both drugs have the same active ingredients. In fact, doctors use a person’s levodopa dosage from their immediate-release carbidopa/levodopa oral tablets (such as Sinemet) to determine their Duopa dosage.

However, doctors use a series of calculations to convert the doses. This is because the forms and how you take Duopa and Sinemet are different. Duopa is given as a direct infusion to your small intestine. You typically use it daily for 16 hours. Sinemet is typically taken three or four times per day.

Your doctor will prescribe the drug and the dosage that’s right for you. To learn more about how these drugs compare, talk with your doctor.

How long does it take for Duopa to start working?

Duopa starts to work quickly. After your pump starts delivering the drug, Duopa reaches peak levels in your body at around 2.5 hours. That’s likely when you’ll notice the drug’s greatest effect. However, you may notice your symptoms starting to improve earlier.

You can talk with your doctor if you have questions about what to expect with Duopa treatment. You can also read this article for more information.

If your doctor recommends Duopa for you, they’ll prescribe the dosage that’s right for you. Always follow the dosage that your doctor prescribes.

As with any drug, never alter your dosage of Duopa without your doctor’s recommendation. If you have questions about the dosage of Duopa that’s best for you, talk with your doctor.

Besides learning about dosage, you may want other information about Duopa. These additional articles might be helpful:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.