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Carbidopa (By mouth)

Carbidopa (kar-bi-DOE-pa)

Used in combination with levodopa, or Sinemet®, to treat symptoms of Parkinson's disease, such as shaking, stiffness, and slow movement.

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to carbidopa, or if you have narrow-angle glaucoma. Do not use this medicine if you are using an MAO inhibitor (such as Nardil®, Marplan®, or Parnate®) or have used one within the past 14 days. You should not use this medicine if you think you might have melanoma (skin cancer) or if you have a history of melanoma.

How to Use This Medicine:


  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Take this medicine at the same time you take your levodopa or Sinemet®.
  • You may take this medicine with or without food.

If a dose is missed:

  • You must use this medicine on a fixed schedule. Call your doctor or pharmacist if you miss a dose.

How to Store and Dispose of This Medicine:

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Make sure your doctor knows if you are using papaverine (Pavabid®), metoclopramide (Reglan®), the MAO inhibitor selegiline (Eldepryl®), phenytoin (Dilantin®), isoniazid (Nydrazid®), haloperidol (Haldol®), or risperidone (Risperdal®). Tell your doctor if you are using phenothiazines (such as Compazine®, Mellaril®, Phenergan®, Serentil®, Tacaryl®, Thorazine®, Trilafon®), medicine for depression (such as amitriptyline, nortriptyline, Norpramin®, Vivactil®), or vitamin supplements that contain iron.
  • Make sure your doctor knows if you are also using medicine to decrease your blood pressure. Some blood pressure medicines are atenolol, hydrochlorothiazide (HCTZ), lisinopril, metoprolol, Accupril®, Cozaar®, Diovan®, Lotrel®, Norvasc®, Prinivil®, Toprol®, and Zestril®.
  • Tell your doctor if you drink alcohol or if you are using any medicine that makes you sleepy, such as allergy medicine or narcotic pain medicine.
  • Avoid eating a high-protein diet while you are using this medicine.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breast feeding, or if you have a history of mental or emotional problems. Your doctor needs to know if you have kidney disease, liver disease, lung disease (including asthma or emphysema), or a stomach ulcer. If you have problems with your endocrine system, tell your doctor. This system is made up of glands that produce hormones to control body functions. Endocrine system problems include diabetes, thyroid problems, or growth problems. Tell your doctor if you have had a heart attack, or if you have heart disease or low blood pressure.
  • Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests, including tests often used by people who have diabetes.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
  • Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
  • This medicine might cause your saliva, sweat, or urine to become dark red, brown, or black. This may stain clothing, but is otherwise harmless.
  • This medicine may make you dizzy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Clenching or grinding your teeth.
  • Depression, or thoughts of hurting yourself.
  • Hallucinations (seeing or hearing things that are not truly there).
  • High fever, severe muscle pain or stiffness, or confusion.
  • Light-headedness, fainting, or fast heartbeat.
  • Repetitive movements you cannot control (either new or worse than usual).
  • Severe anxiety or agitation.

If you notice these less serious side effects, talk with your doctor:

  • Dry mouth, or headache.
  • Loss of appetite.
  • Mild diarrhea, constipation.
  • Mild nausea, vomiting, or stomach pain.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 4/4/2014

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