Medical Editor: John P. Cunha, DO, FACOEP Last updated on RxList: 11/9/2021
Duopa Side Effects Center

What Is Duopa?

Duopa (carbidopa and levodopa) is a combination of an inhibitor of aromatic amino acid decarboxylation and an aromatic amino acid used to treat motor fluctuations in patients with advanced Parkinson's disease.

What Are Side Effects of Duopa?

Common side effects of Duopa include:

Dosage for Duopa

The maximum recommended daily dose of Duopa is 2000 mg of the levodopa component (i.e., one cassette per day) administered over 16 hours.

What Drugs, Substances, or Supplements Interact with Duopa?

Duopa may interact with MAO inhibitors, high blood pressure medications, phenothiazines, butyrophenones, risperidone, metoclopramide, papaverine, isoniazid, iron salts or multi-vitamins containing iron salts, and high protein diets. Tell your doctor all medications and supplements you use.

Duopa During Pregnancy and Breastfeeding

During pregnancy, Duopa should be administered only if prescribed. This drug may pass into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Duopa (carbidopa and levodopa) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Duopa Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • nausea, vomiting, stomach pain, fever;
  • ongoing constipation, bloody or tarry stools;
  • cough, trouble breathing;
  • pain, swelling, redness, warmth, or oozing around the tube in your stomach wall;
  • uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
  • a light-headed feeling, like you might pass out;
  • chest pain, fast or irregular heartbeats;
  • daytime sleepiness or if you suddenly fall asleep after being alert;
  • numbness or weakness in your hands or feet; or
  • hallucinations, depression or suicidal thoughts.

Some people using Duopa have fallen asleep during normal daytime activities such as working, talking, eating, or driving. Tell your doctor if you have any problems with daytime sleepiness or drowsiness.

You may have increased sexual urges, unusual urges to gamble, or other intense urges. Talk with your doctor if this occurs.

Common side effects may include:

  • increased blood pressure;
  • swelling in your lower legs;
  • nausea;
  • depression; or
  • mouth or throat pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Duopa (Carbidopa and Levodopa Enteral Suspension)


Parkinson's disease is only seen in people of advanced age. See Answer
Duopa Professional Information


The following serious adverse reactions are discussed below and elsewhere in labeling:

  • Gastrointestinal and Gastrointestinal Procedure-Related Risks [see WARNINGS AND PRECAUTIONS]
  • Falling Asleep During Activities of Daily Living and Somnolence [see WARNINGS AND PRECAUTIONS]
  • Orthostatic Hypotension [see WARNINGS AND PRECAUTIONS]
  • Hallucinations/Psychosis/Confusion [see WARNINGS AND PRECAUTIONS]
  • Impulse Control/Compulsive Behaviors [see WARNINGS AND PRECAUTIONS]
  • Depression and Suicidality [see WARNINGS AND PRECAUTIONS]
  • Withdrawal-Emergent Hyperpyrexia and Confusion [see WARNINGS AND PRECAUTIONS]
  • Cardiovascular Ischemic Events [see WARNINGS AND PRECAUTIONS]
  • Laboratory Test Abnormalities [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical studies are run under widely varying conditions, the incidence of adverse reactions observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In clinical studies, 416 patients with advanced Parkinson's disease received DUOPA. 338 patients were treated with DUOPA for more than 1 year, 233 patients were treated with DUOPA for more than 2 years, and 162 patients were treated with DUOPA for more than 3 years.

In a 12-week, active-controlled clinical trial (Study 1), a total of 71 patients with advanced Parkinson's disease were enrolled and had a PEG-J procedure. Of these, 37 patients received DUOPA and 34 received oral immediate-release carbidopa-levodopa.

The most common adverse reactions for DUOPA (incidence at least 7% greater than oral immediate-release carbidopa-levodopa) were: complication of device insertion, nausea, depression, peripheral edema, hypertension, upper respiratory tract infection, oropharyngeal pain, atelectasis, and incision site erythema.

Table 3 lists the incidence of adverse reactions occurring in the DUOPA-treated group (requiring at least 2 patients in this group) in Study 1 when the incidence was numerically greater than that for oral immediate-release carbidopa-levodopa.

Table 3: Adverse Reactions in Study 1 for DUOPA in Patients with Advanced Parkinson's Disease

Preferred TermDUOPA
(n = 37) %
Oral immediate-release carbidopa-levodopaa
(n = 34) %
Complication of device insertion5744
Incision site erythema1912
Post procedural discharge119
Peripheral edema80
Upper respiratory tract infection80
Oropharyngeal pain80
Confusional state83
Hiatal hernia86
Postoperative ileus50
Sleep disorder50
Excessive granulation tissue50
White blood cells urine positive50
Psychotic disorder53
aAll patients in the clinical trial regardless of treatment arm received a PEG-J.

Procedure And Device- Related Adverse Reactions

The most common adverse reactions associated with complications due to naso-jejunal (NJ) insertion were: oropharyngeal pain, abdominal distention, abdominal pain, abdominal discomfort, pain, throat irritation, gastrointestinal injury, esophageal hemorrhage, anxiety, dysphagia, and vomiting.

The most common adverse reactions associated with complications due to PEG-J insertion were: abdominal pain, abdominal discomfort, abdominal distension, flatulence, or pneumoperitoneum.

Additional adverse reactions that were co-reported with complication of naso-jejunal and PEG-J insertion included upper abdominal pain, duodenal ulcer, duodenal ulcer hemorrhage, erosive duodenitis, erosive gastritis, gastrointestinal hemorrhage, intussusception, peritonitis, postoperative abscess, and small intestine ulcer.

Read the entire FDA prescribing information for Duopa (Carbidopa and Levodopa Enteral Suspension)

© Duopa Patient Information is supplied by Cerner Multum, Inc. and Duopa Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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