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Drug Profile

The information on this site is intended to supplement and enhance, not replace, the advice of a physician who is familiar with your medical history. Decisions about your health should always be made ONLY after detailed conversation with your doctor.

Generic drug name: levodopa and carbidopa (LEE voe doe pa and KAR bi doe pa)
Brand name(s): DUOPA, PARCOPA, RYTARY, SINEMET, SINEMET CR
GENERIC: available FAMILY: Drugs for Parkinson’s Disease
Find the drug label by searching at DailyMed.

Pregnancy and Breast-feeding Warnings [top]

Pregnancy Warning

Levodopa and carbidopa caused fetal harm in animal studies, including malformations and death. Because of the potential for serious adverse effects to the fetus, this drug should not be used by pregnant women.

Breast-feeding Warning

No information is available from either human or animal studies. Since it is likely that this drug, like many others, is excreted in human milk, and because of the potential for adverse effects in nursing infants, you should not take this drug while nursing.

Facts About This Drug [top]

The combination of levodopa and carbidopa (SINEMET) is used to treat Parkinson’s disease, a condition that produces tremors (shaking), rigid muscles and disturbances in posture, walking, balance, speech, swallowing and muscle strength. This combination is the better choice for treating Parkinson’s disease than levodopa alone, because carbidopa prevents the breakdown of levodopa in the body.

The editors of The Medical Letter, a respected independent source of drug information, say that “the...

The combination of levodopa and carbidopa (SINEMET) is used to treat Parkinson’s disease, a condition that produces tremors (shaking), rigid muscles and disturbances in posture, walking, balance, speech, swallowing and muscle strength. This combination is the better choice for treating Parkinson’s disease than levodopa alone, because carbidopa prevents the breakdown of levodopa in the body.

The editors of The Medical Letter, a respected independent source of drug information, say that “the combination of these two drugs is the most effective treatment available for symptomatic relief of Parkinson’s disease.”[1]

Levodopa is effective for the majority of patients during the first two to five years of therapy. As the course of the disease progresses, the duration of benefit of a dose becomes shorter. This is known as the “wearing off” effect. Some patients develop sudden, unpredictable fluctuations between being able to move and not being able to move. This is referred to as the “on-off” effect.[1]

Maximizing effectiveness through diet

Patients who take levodopa alone should avoid foods and vitamins that contain vitamin B6 (pyridoxine), since this vitamin can destroy the drug’s effectiveness. To keep your intake of vitamin B6 down, you should avoid multiple vitamins, avocados, beans, peas, sweet potatoes, dry skim milk, oatmeal, pork, bacon, beef liver, tuna and cereals fortified with vitamin B6. If you take carbidopa and levodopa, you do not need to worry about this.

Avoid drug-induced disease

If you have symptoms of parkinsonism (tremor, rigid muscles, and disturbances in posture, walking, balance, speech, swallowing and muscle strength), there is a good chance that they are caused by a drug you are taking. As many as half of older adults with symptoms of parkinsonism may have developed them as adverse effects of a drug. (See the section that lists drugs that can cause symptoms of parkinsonism.)

If you take any of the drugs on this list, discuss the possibility of drug-induced parkinsonism with your doctor and ask to have your prescription changed or stopped.

Regulatory actions surrounding SINEMET

2009: The patient package insert for SINEMET has been updated to include information on reports of an intense urge to gamble, increased sexual urges and other intense urges (and the inability to control these urges) in patients using this drug. In some cases the urges were stopped when the drug was decreased or stopped. However it has not been proven that the drug caused these events.[2]

Before You Use This Drug [top]

Tell your doctor if you have or have had:

  • allergies to carbidopa and/or levodopa
  • pregnancy or are breast-feeding
  • bronchial emphysema, asthma, or other chronic lung disease
  • heart or blood vessel disease
  • diabetes
  • hormone problems
  • skin cancer
  • glaucoma
  • stomach ulcer
  • seizure disorder or epilepsy
  • kidney disease
  • liver problems
  • mental depression or psychosis

Tell your doctor about any other drugs you take, including aspirin, herbs, vitamins, and other nonprescription products.

When You Use This Drug [top]

  • Maximum effectiveness of drug may not occur for several weeks or months after starting therapy.
  • Until you know how you react to this drug, do not drive or perform other activities requiring alertness. This drug can cause faintness and lightheadedness.
  • You may feel dizzy when rising from a lying or sitting position. When getting out of bed, hang your legs over the side of the bed for a few minutes, then get up slowly. When getting up from a chair, stay by the chair until you are sure that you are not dizzy.
  • Caution diabetics: This drug may interfere with urine tests for sugar and ketones.
  • If you plan to have any surgery, including dental, tell your doctor that you take this drug.
  • You may experience difficulty in retaining full dentures.
  • Drug may darken urine, saliva, or sweat.

How to Use This Drug [top]

  • Take with meals or snacks for the first few months until tolerance for the stomach side effects occurs. Then, take with water only. Do not eat or drink for about an hour before taking this medication. An empty stomach is necessary for this drug to be absorbed maximally.
  • If you miss a dose, take it as soon as you remember, but skip it if it is within two hours of the next dose. Do not take double doses.
  • Do not share your medication with others.
  • Take the drug at the same time(s) each day.
  • Store at room temperature with lid on tightly. Do not store in the bathroom. Do not expose to heat, moisture, or strong light. Keep out of reach of children.

Interactions with Other Drugs [top]

The following drugs, biologics (e.g., vaccines, therapeutic antibodies), or foods are listed in Evaluations of Drug Interactions 2003 as causing “highly clinically significant” or “clinically significant” interactions when used together with any of the drugs in this section. In some sections with multiple drugs, the interaction may have been reported for one but not all drugs in this section, but we include the interaction because the drugs in this section are similar to one another. We have also included potentially serious interactions listed in the drug’s FDA-approved professional package insert or in published medical journal articles. There may be other drugs, especially those in the families of drugs listed below, that also will react with this drug to cause severe adverse effects. Make sure to tell your doctor and pharmacist the drugs you are taking and tell them if you are taking any of these interacting drugs:

amitriptyline, chlorpromazine, DILANTIN, ELAVIL, HALDOL, haloperidol, INH, iron supplements, isoniazid, metoclopramide, NARDIL, phenelzine, phenytoin, pyridoxine (vitamin B6), REGLAN, RISPERDAL, risperidone, selegiline, THORAZINE.

Adverse Effects [top]

Call your doctor immediately if you experience:

  • agitation
  • anxiety
  • clumsiness or unsteadiness
  • clenching or grinding of teeth
  • unusual and uncontrolled body movements, including of the face, tongue, arms, hands, head, and upper body
  • confusion
  • abnormal thinking
  • dizziness
  • difficulty swallowing
  • false sense of well-being
  • unusual tiredness or weakness
  • feeling faint
  • hallucinations
  • increased hand tremor
  • general feeling of discomfort or illness
  • nausea or vomiting
  • numbness, burning, tingling, or prickling sensations
  • excessive mouth watering
  • increased eyelid blinking or spasm
  • blurred vision
  • fast, irregular, or pounding heartbeat
  • double vision
  • hot flashes
  • dilated pupils
  • mood or mental changes
  • dizziness or lightheadedness when getting up from a lying or sitting position
  • skin rash
  • difficulty opening mouth
  • unusual weight gain or loss
  • appetite loss
  • loss of urinary bladder control
  • difficulty urinating
  • chills
  • fever
  • sore throat
  • stomach pain
  • facial swelling
  • swelling of feet or lower legs
  • bloody or black, tarry stools
  • vomiting blood or vomit that looks like coffee grounds
  • back or leg pain
  • pale skin
  • high blood pressure
  • inability to move eyeballs
  • prolonged, painful, or inappropriate penile erection
  • convulsions

Call your doctor if these symptoms continue:

  • abdominal pain
  • appetite loss
  • dry mouth
  • passing gas
  • nightmares
  • constipation
  • diarrhea
  • skin flushing
  • headache
  • hiccups
  • increased sweating
  • trouble sleeping
  • muscle twitching
  • unusual tiredness or weakness

Signs of overdose:

  • increased eyelid blinking or spasms

If you suspect an overdose, call this number to contact your poison control center: (800) 222-1222.

Periodic Tests[top]

Ask your doctor which of these tests should be done periodically while you are taking this drug:

  • complete blood count
  • liver function tests
  • kidney function tests
  • eye pressure tests
  • cardiovascular monitoring

last reviewed June 30, 2021