Duopa (carbidopa/levodopa) is a prescription drug used to treat advanced Parkinson’s disease. The drug comes as a liquid suspension. It’s given over 16 hours each day through a tube that goes into your small intestine.

Specifically, Duopa is used to treat motor fluctuations in adults with advanced Parkinson’s disease (PD).

Duopa contains two active ingredients* that work together to increase dopamine levels in the brain:

  • levodopa, which belongs to a group of drugs called dopamine precursors
  • carbidopa, which belongs to a group of drugs called decarboxylase inhibitors

This article describes the dosages of Duopa, as well as its strength and how to take it. To learn more about this medication, see this in-depth article.

* An active ingredient is what makes a drug work.

Keep reading for more details about Duopa’s dosage.

What is Duopa’s form?

Duopa comes as a liquid suspension in single-dose containers called cassettes. More specifically, Duopa is an enteral suspension. This means it’s a liquid that’s administered directly into your digestive tract through a special tube. You’ll likely have a procedure done to make this tube placement possible.

Before you start Duopa treatment, a healthcare professional will show you or a caregiver how to administer Duopa. (See “How is Duopa administered” below for more information.)

What strength does Duopa come in?

Duopa comes in only one strength. Each milliliter (mL) of Duopa contains 4.63 milligrams (mg) of carbidopa and 20 mg of levodopa. One cassette contains a total of 100 mL.

What are the usual dosages of Duopa?

Before starting Duopa your doctor will prescribe levodopa/carbidopa immediate-release tablets to determine the dosage of Duopa you will need. Levodopa is typically not used alone.

Dosage for PD

There isn’t a typical dosage of Duopa for adults with advanced PD. Instead, your doctor will determine an individualized dosage and may adjust it depending on how your body responds to the drug. These adjustments are especially common when you first start Duopa treatment.

Your doctor will program your dosage into the pump device. You won’t be able to change the programming on your own at home. In some cases, they may set up your pump to allow for extra doses or certain dose changes. Talk with them before administering extra doses or changing your dose of Duopa.

The maximum recommended dosage of Duopa is one cassette per day, given over 16 hours. One cassette contains 463 mg of carbidopa and 2,000 mg of levodopa.

Talk with your doctor before stopping Duopa. This medication should not be stopped suddenly. Doing so can cause side effects such as confusion, fever, and severe muscle stiffness.

Is Duopa used long term?

Yes, Duopa is usually used as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely use it long term.

The dosage of Duopa you’re prescribed may depend on several factors. These include:

  • the dosage of oral carbidopa/levodopa you took before starting Duopa
  • the severity of your condition
  • how your body responds to the medication

Before you start Duopa treatment, a healthcare professional will show you or a caregiver how to take Duopa. (Note that “you” in this section refers to you or your caregiver.)

Duopa is an enteral suspension. This means it’s a liquid that’s given directly into your digestive tract through a special (PEG-J) tube. You’ll likely have a procedure done to make this tube placement possible. (Before having this procedure, you may temporarily use a nasojejunal tube* to administer Duopa.)

Duopa comes in single-dose containers called cassettes. You’ll attach a cassette to a small, portable pump. Then you’ll connect the cassette to your PEG-J tube and turn on the pump.

Your daily dose will be delivered over the next 16 hours. The dose amount is already programmed into the pump device by your doctor. Afterward, you’ll disconnect the pump, discard the cassette, and flush your tube with water.

You’ll typically set up your Duopa treatment in the morning, then disconnect it in the evening (16 hours later).

Be sure to follow your doctor’s directions for taking Duopa. Instructions are also available on the drugmaker’s website. For information on the expiration, storage, and disposal of Duopa, talk with your doctor or pharmacist.

*This is a thin tube passed through your nose and stomach and into a part of your small intestine.

Accessible drug containers and labels

Some pharmacies provide medication labels that:

  • have large print
  • use braille
  • feature a code you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.

If you’re not sure what to do about a missed dose of Duopa, talk with your doctor. They can also tell you what to do if you need to disconnect the Duopa pump for a short time (to have a medical procedure, for example).

As a backup, your doctor will likely prescribe another medication (such as carbidopa/levodopa oral tablets) to take if you’re temporarily unable to take Duopa.

If you need help remembering to take Duopa on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Do not take more Duopa than your doctor prescribes, as this can lead to harmful effects.

What to do in case you take too much Duopa

Call your doctor right away if you think you’ve taken too much Duopa. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number), or go to the nearest emergency room.

If you suddenly stop Duopa treatment, you may experience uncomfortable symptoms. These may include confusion, fever, and severe muscle stiffness.

Before you end your Duopa treatment, your doctor will likely lower your dosage slowly over time. Or they may switch you to an oral form of carbidopa/levodopa instead. (These are the active ingredients in Duopa and other medications used for PD.) These options can help prevent side effects that could occur from suddenly stopping Duopa.

Below are answers to some commonly asked questions about Duopa’s dosage.

Is Duopa’s dosage similar to that of Sinemet or Azilect?

No. All three of these medications are approved for treating PD, but they all have different dosages.

Duopa comes as a liquid suspension that’s given over the course of 16 hours each day through a tube that goes into your small intestine.

Sinemet (carbidopa/levodopa) and Azilect (rasagiline) come as oral tablets. With Sinemet, you’ll likely take three to four doses throughout the day. With Azilect, you’ll usually take one dose daily.

For some people, switching to Duopa eliminates the need to take oral medications for PD. Some people may still need to take an evening dose of oral carbidopa/levodopa after disconnecting Duopa, though. Your doctor will recommend a treatment plan that suits your needs.

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 during your first dose. You and your doctor will monitor your symptoms during treatment to check whether the drug is working to treat your motor fluctuations.

Your doctor may monitor you especially closely during your first several days of treatment to determine whether your dosage needs to be adjusted. They’ll program your dosage in the pump device that’s used to administer doses of Duopa.

If you have other questions about what to expect from your Duopa treatment, talk with your doctor.

The sections above describe the dosage information provided by Duopa’s manufacturer. If your doctor recommends this drug, they’ll prescribe the dosage that’s right for you.

You should not change your dosage of Duopa without your doctor’s recommendation. Take the drug exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage. Examples of questions you may want to ask them include:

  • Does the amount of protein in my diet affect my dosage of Duopa?
  • What is our plan for monitoring how well my dosage is working and, if needed, making dosage adjustments?
  • When should I take an extra dose of Duopa or a supplemental dose of oral carbidopa/levodopa?

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Disclaimer: Healthline 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.