Carbidopa/levodopa | Side Effects, Dosage, Uses & More
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Generic Name:

carbidopa-levodopa, Oral tablet

All Brands

  • SINEMET
SECTION 1 of 5

Highlights for carbidopa-levodopa

Oral tablet
1

Carbidopa/levodopa is used to treat the symptoms of Parkinson’s disease. Symptoms include shaking, stiffness, and slow movement. Carbidopa/levodopa is also used to treat parkinsonism (Parkinson’s-like symptoms) from encephalitis (swelling of the brain). This drug is also used to treat symptomatic parkinsonism due to injury of the nervous system from carbon monoxide or manganese intoxication.

2

This drug comes in the forms of an immediate-release tablet, extended-release tablet, extended-release capsule, and orally disintegrating tablet. You take these forms by mouth.  It also comes as an enteral suspension.  You take this form through a feeding tube that goes directly into your small intestine.

3

Carbidopa/levodopa is available as the following brand-name drugs: Sinemet (oral tablet), Sinemet CR (extended-release tablet), Rytary (oral extended-release capsule), and Duopa (enteral suspension). The immediate-release, extended-release, and orally disintegrating tablets are also available as generic drugs.

4

The more common side effects of this drug can include nausea, dizziness, headache, and insomnia. They can also include strange dreams, dry mouth, and involuntary body movements.

5

In some cases, this drug can cause serious side effects. These include an increased risk for drowsiness and falling asleep suddenly. You shouldn’t drive, use machinery, or do other activities that require alertness until you know how this drug affects you. 

IMPORTANT INFORMATION

Drowsiness and falling asleep suddenly

This drug may raise your risk for drowsiness and falling asleep suddenly. You shouldn’t drive, use machinery, or do other activities that require alertness until you know how this drug affects you. Tell your doctor right away if you have unexplained drowsiness or fall asleep suddenly.

Neuroleptic malignant syndrome

Reducing or stopping this drug suddenly may raise your risk of neuroleptic malignant syndrome. This is an uncommon but life-threatening condition. It involves a fever, stiff muscles, and involuntary body movements. It can also cause mental health problems, sweating, and increased heart and breathing rates. Call your doctor right away if you have any of these symptoms.

Phenylketonuria

The orally disintegrating tablet contains phenylalanine. You shouldn’t take this form of the drug if you have phenylketonuria.

What is carbidopa/levodopa?

Carbidopa/levodopa is a prescription drug. It’s available in these forms: oral tablet, oral extended-release tablet, orally disintegrating tablet, extended-release capsule, and enteral suspension.

This drug is available as a generic drug.  Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.

This drug is a combination drug. It contains 2 drugs:  carbidopa and levodopa. It’s important to know about all the drugs in the combination because each drug may affect you in a different way.

Carbidopa/levodopa may be used as part of combination therapy. This means you may have to take it with other medications for Parkinson’s disease.

Why it's used

This drug is used to treat the symptoms of Parkinson’s disease. It’s also used to treat parkinsonism (Parkinson’s-like symptoms) that develops after encephalitis (swelling of the brain). This drug is also used to treat parkinsonism due to injury of the nervous system from carbon monoxide and/or manganese intoxication. This is called symptomatic parkinsonism. Symptoms of these conditions include shaking, stiffness, and slow movement.

How it works

This medication contains two drugs: carbidopa and levodopa. Carbidopa belongs to a class of drugs called decarboxylase inhibitors. Levodopa belongs to a class of drugs called dopamine precursors. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

More Details

How it works

This medication contains two drugs: carbidopa and levodopa. Carbidopa belongs to a class of drugs called decarboxylase inhibitors. Levodopa belongs to a class of drugs called dopamine precursors. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Parkinson’s disease is caused by a lack of dopamine in the brain. Levodopa works by converting into dopamine in the brain. Carbidopa works by stopping levodopa from breaking down before it reaches the brain.

Using the two drugs together allows for a lower dose of levodopa. A lower dose reduces your risk of side effects from levodopa, such as nausea and vomiting.

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SECTION 2 of 5

carbidopa-levodopa Side Effects

Oral tablet

More Common Side Effects

Some of the more common side effects of carbidopa/levodopa include:

  • nausea

  • dizziness

  • insomnia

  • strange dreams

  • dry mouth

  • involutnary body movements

  • anxiety

  • constipation

  • vomiting

  • orthostatic hypotension (low blood pressure when you stand up)

If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious Side Effects

Call your doctor right away if you have serious side effects. Call 9-1-1 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Sleep effects. Symptoms can include:

    • extreme drowsiness
    • suddenly falling asleep
  • Neuroleptic malignant syndrome. Symptoms can include:

    • fever
    • stiff muscles
    • involuntary muscle movements
    • confusion
    • decreased awareness
    • sweating
    • increased heart and breathing rate
  • Mental health problems. Symptoms can include:

    • hallucinations (seeing or hearing things that aren’t real)
    • delusions (having false thoughts)
    • confusion
    • aggressive behavior
    • distrust or irrational suspicion of others
    • agitation
    • intense urges to gamble, have sex, spend money, or binge eat
  • Melanoma (skin cancer). It isn’t clear if this risk is due to Parkinson’s disease or the drugs that are used to treat it. Symptoms can include:

    • blue or blue-black colored lesions (areas of damaged tissue)
    • lesions or spots with more than one color, or that have flecks of a different color
    • a mole or spot that changes in color or size over time
    • lesions with irregular borders
  • Heart effects. Symptoms can include:

    • angina (chest pain)
    • heart attack
    • fast heart rate
    • arrhythmia  (irregular heart beat)
    • palpitations  (feeling like your heart is skipping beats)
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug causes drowsiness. You shouldn’t drive, use machinery, or do other activities that require alertness until you know how it affects you.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 5

carbidopa-levodopa May Interact with Other Medications

Oral tablet

Carbidopa/levodopa can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.

To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Alcohol interaction

The use of drinks that contain alcohol can increase your risk of sedative side effects from this drug. You may have slowed reflexes, poor judgment, and sleepiness. This could be dangerous. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Antipsychotic drugs

Certain antipsychotic drugs may reduce the effectiveness of levodopa. This interaction may cause your Parkinson’s disease symptoms to get worse.

These drugs include:

  • chlorpromazine
  • fluphenazine
  • haloperidol
  • risperidone
  • quetiapine
  • olanzapine

Nausea and vomiting drugs

Certain drugs used to treat nausea and vomiting may reduce the effectiveness of levodopa. This interaction may cause your Parkinson’s disease symptoms to get worse.

These drugs include:

  • promethazine
  • prochlorperazine
  • metoclopramide

Antibiotics

Certain antibiotics may reduce the effectiveness of levodopa. This interaction may cause your Parkinson’s disease symptoms to get worse.

These drugs include:

  • isoniazid

Iron

Iron and multivitamins that contain iron can cling to carbidopa/levodopa. This means that your body may not be able to absorb the drug as well. This interaction may cause your Parkinson’s disease symptoms to get worse.

Depression drugs

Certain depression drugs may increase the levels of carbidopa/levodopa in your body. This interaction increases your risk of side effects. It may cause your blood pressure to drop to very low levels. You shouldn’t take these depression drugs with carbidopa/levodopa.

These drugs include:

  • monoamine oxidase inhibitors (MAOIs), such as:
    • selegiline
    • isocarboxazid
    • phenelzine
    • tranylcypromine

 

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Drug warnings
glaucoma
People with glaucoma

This drug can increase the pressure in your eyes. If you have glaucoma, this drug can make your vision worse. If you have narrow-angle glaucoma, this drug can lead to permanent vision loss.  People with narrow-angle glaucoma shouldn’t use the immediate-release, extended-release, or orally disintegrating tablets. Ask to your doctor whether the extended-release capsules or enteral suspension is safe for you.  If you have chronic, wide-angle glaucoma, ask your doctor whether this drug is safe for you.

severe heart disease
People with severe heart disease

In rare cases, this drug has been linked to heart disease. Heart disease includes angina (chest pain), heart attack, and arrhythmias (irregular heart rhythms). If you have a history of heart disease, your risk for these events is higher. Talk to your doctor about whether this drug is safe for you.

lung disease
People with severe lung disease or asthma

This drug can cause shortness of breath in some people. If you already have trouble breathing due to asthma or chronic obstructive pulmonary disease (COPD), talk to your doctor about whether this drug is safe for you.

kidney disease
People with kidney disease

Your kidneys help remove this drug from your body. If you have kidney problems, this drug may build up in your body. This buildup can increase your risk for side effects. Talk to your doctor about whether this drug is safe for you.

liver disease
People with liver disease

Your liver helps remove this drug from your body. If you have liver problems, this drug may build up in your body. This buildup can increase your risk for side effects. Talk to your doctor about whether this drug is safe for you.

endocrine disease
People with endocrine disease

This drug can interfere with a certain urine test that is used to diagnose endocrine disorders. Some people taking this drug have been falsely diagnosed with the endocrine disorder pheochromocytoma. Talk to your doctor about whether this drug is safe for you or ask if it may interfere with any lab tests.

peptic ulcers
People with a history of peptic ulcers

If you have a history of peptic ulcers, this drug can increase your risk of stomach or intestinal bleeding. Talk to your doctor about whether this drug is safe for you.

pregnant women
Pregnant women

This drug is a category C pregnancy drug. That means two things:

  1. Research in animals has shown adverse effects to the fetus when the mother takes the drug.
  2. There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. This drug should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus.

breastfeeding
Women who are breast-feeding

This drug passes into breast milk and may cause side effects in a child who is breastfed.

Talk to your doctor if you breastfeed your baby. You may need to decide whether to stop breastfeeding or stop taking this medication.

for seniors
For seniors

Older adults may process drugs more slowly. A typical adult dose may cause levels of the drug to be higher than normal in older adults. 

Seniors also have a higher risk for mental health changes from this drug. These changes can include hallucinations (seeing or hearing things that aren’t there), confusion, and agitation. If you’re a senior, you may need a lower dose or a different schedule. 

for children
For children

This drug hasn’t been studied in children. It shouldn’t be used in children under 18 years of age.

allergies
Allergies

This drug can cause a severe allergic reaction. Symptoms can include:

  • swelling of your face, lips, tongue, or throat
  • trouble breathing
  • rash
  • hives

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal (cause death).

SECTION 4 of 5

How to Take carbidopa-levodopa (Dosage)

Oral tablet

All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What are you taking this medication for?

Parkinson's disease

Generic: carbidopa/levodopa

Form: Orally disintegrating tablet
Strengths: 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Sinemet

Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa

Brand: Sinemet CR

Form: Oral extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Rytary

Form: Oral extended-release capsule
Strengths: 23.75 mg carbidopa/95 mg levodopa, 36.25 mg carbidopa/145 mg levodopa, 48.75 mg carbidopa/195 mg levodopa, 61.25 mg carbidopa/245 mg levodopa

Brand: Duopa

Form: Enteral suspension
Strengths: 4.63 mg carbidopa/20 mg levodopa per 1 mL of suspension
Adult dosage (ages 18–64 years)
  • Oral tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken three times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Oral extended-release tablet:
    • The starting dose is 50 mg carbidopa/200 mg levodopa taken two times per day. Your doctor may change your dose based on how you respond to this drug. You should take your doses 4 to 8 hours apart while you’re awake. Your doctor will tell you how often to take this drug.
  • Oral extended-release capsule:
    • If you are already taking carbidopa/levodopa in another form, your dose will depend on your current dosage of the levodopa. Your new dosage of levodopa will be 1.5–2 times your old dosage from the immediate-release tablets.
    • The recommended starting dose if you aren’t already taking carbidopa/levodopa is 23.75 mg carbidopa/95 mg levodopa taken 3 times per day for the first 3 days. On the fourth day, your doctor may increase your dose up to 36.25 mg carbidopa/145 mg levodopa taken 3 times per day. Your doctor may increase your dose up to a maximum of 97.5 mg carbidopa/390 mg levodopa take 3 times per day. You may have to take this drug up to 5 times per day if needed and tolerated.
  • Orally disintegrating tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken 3 times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Enteral suspension:
    • You take this form over a 16-hour period through a feeding tube that goes to your small intestine.
    • You’ll receive a larger morning dose that you take for 10–30 minutes. This dose will be followed by a continuous infusion over the remaining time.
    • You’ll have the option to give extra doses as need to control your symptoms. Extra doses typically start at 1 mL (4.63 mg carbidopa/20 mg levodopa). You shouldn’t use the extra dose function more than once every 2 hours.
    • Your dose will depend on how you respond to the drug. It will also depend on how much levodopa/carbidopa you’ve been taking.
Child dosage (ages 0–17 years)

Sinemet has not been studied in children. It shouldn’t be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dose may cause levels of the drug to be higher than normal in older adults. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

Enteral suspension:

  • This drug comes in a 100 mL cassette. You should only use these cassettes one time each. They’re designed to run for the 16-hour period.  Don’t reuse the cassette or run it longer than 16 hours, even if some of the drug is left.  
  • You should disconnect the feeding tube after 16 hours and flush it with water.

Postencephalitis parkinsonism

Generic: carbidopa/levodopa

Form: Orally disintegrating tablet
Strengths: 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Sinemet

Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa

Brand: Sinemet CR

Form: Oral extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Rytary

Form: Oral extended-release capsule
Strengths: 23.75 mg carbidopa/95 mg levodopa, 36.25 mg carbidopa/145 mg levodopa, 48.75 mg carbidopa/195 mg levodopa, 61.25 mg carbidopa/245 mg levodopa

Brand: Duopa

Form: Enteral suspension
Strengths: 4.63 mg carbidopa/20 mg levodopa per 1 mL of suspension
Adult dosage (ages 18–64 years)
  • Oral tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken three times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Oral extended-release tablet:
    • The starting dose is 50 mg carbidopa/200 mg levodopa taken two times per day. Your doctor may change your dose based on how you respond to this drug. You should take your doses 4 to 8 hours apart while you’re awake. Your doctor will tell you how often to take this drug.
  • Oral extended-release capsule:
    • If you are already taking carbidopa/levodopa in another form, your dose will depend on your current dosage of the levodopa. Your new dosage of levodopa will be 1.5–2 times your old dosage from the immediate-release tablets.
    • The recommended starting dose if you aren’t already taking carbidopa/levodopa is 23.75 mg carbidopa/95 mg levodopa taken 3 times per day for the first 3 days. On the fourth day, your doctor may increase your dose up to 36.25 mg carbidopa/145 mg levodopa taken 3 times per day. Your doctor may increase your dose up to a maximum of 97.5 mg carbidopa/390 mg levodopa take 3 times per day. You may have to take this drug up to 5 times per day if needed and tolerated.
  • Orally disintegrating tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken 3 times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Enteral suspension:
    • You take this form over a 16-hour period through a feeding tube that goes to your small intestine.
    • You’ll receive a larger morning dose that you take for 10–30 minutes. This dose will be followed by a continuous infusion over the remaining time.
    • You’ll have the option to give extra doses as need to control your symptoms. Extra doses typically start at 1 mL (4.63 mg carbidopa/20 mg levodopa). You shouldn’t use the extra dose function more than once every 2 hours.
    • Your dose will depend on how you respond to the drug. It will also depend on how much levodopa/carbidopa you’ve been taking.
Child dosage (ages 0–17 years)

Sinemet has not been studied in children. It shouldn’t be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dose may cause levels of the drug to be higher than normal in older adults. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

Enteral suspension:

  • This drug comes in a 100 mL cassette. You should only use these cassettes one time each. They’re designed to run for the 16-hour period.  Don’t reuse the cassette or run it longer than 16 hours, even if some of the drug is left.  
  • You should disconnect the feeding tube after 16 hours and flush it with water.

Symptomatic parkinsonism

Generic: carbidopa/levodopa

Form: Orally disintegrating tablet
Strengths: 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa
Form: Extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Sinemet

Form: Oral tablet
Strengths: 25 mg carbidopa/100 mg levodopa, 10 mg carbidopa/100 mg levodopa, 25 mg carbidopa/250 mg levodopa

Brand: Sinemet CR

Form: Oral extended-release tablet
Strengths: 50 mg carbidopa/200 mg levodopa, 25 mg carbidopa/100 mg levodopa

Brand: Rytary

Form: Oral extended-release capsule
Strengths: 23.75 mg carbidopa/95 mg levodopa, 36.25 mg carbidopa/145 mg levodopa, 48.75 mg carbidopa/195 mg levodopa, 61.25 mg carbidopa/245 mg levodopa

Brand: Duopa

Form: Enteral suspension
Strengths: 4.63 mg carbidopa/20 mg levodopa per 1 mL of suspension
Adult dosage (ages 18–64 years)
  • Oral tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken three times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Oral extended-release tablet:
    • The starting dose is 50 mg carbidopa/200 mg levodopa taken two times per day. Your doctor may change your dose based on how you respond to this drug. You should take your doses 4 to 8 hours apart while you’re awake. Your doctor will tell you how often to take this drug.
  • Oral extended-release capsule:
    • If you are already taking carbidopa/levodopa in another form, your dose will depend on your current dosage of the levodopa. Your new dosage of levodopa will be 1.5–2 times your old dosage from the immediate-release tablets.
    • The recommended starting dose if you aren’t already taking carbidopa/levodopa is 23.75 mg carbidopa/95 mg levodopa taken 3 times per day for the first 3 days. On the fourth day, your doctor may increase your dose up to 36.25 mg carbidopa/145 mg levodopa taken 3 times per day. Your doctor may increase your dose up to a maximum of 97.5 mg carbidopa/390 mg levodopa take 3 times per day. You may have to take this drug up to 5 times per day if needed and tolerated.
  • Orally disintegrating tablet:
    • The starting dose is 25 mg carbidopa/100 mg levodopa taken 3 times per day. Your doctor may increase your dose by 25 mg carbidopa/100 mg levodopa every day or every other day, as needed, until you’re taking eight 25 mg carbidopa/100 mg tablets per day.
    • If your doctor starts you on the 10 mg carbidopa/100 mg levodopa tablet, you’ll start with one tablet taken 3 or 4 times per day. Your doctor may increase your dosage by one tablet per day or every other day until you’re taking a total of eight 10 mg carbidopa/100 mg levodopa tablets per day (two 10 mg carbidopa/100 mg levodopa tablets taken 4 times per day).
  • Enteral suspension:
    • You take this form over a 16-hour period through a feeding tube that goes to your small intestine.
    • You’ll receive a larger morning dose that you take for 10–30 minutes. This dose will be followed by a continuous infusion over the remaining time.
    • You’ll have the option to give extra doses as need to control your symptoms. Extra doses typically start at 1 mL (4.63 mg carbidopa/20 mg levodopa). You shouldn’t use the extra dose function more than once every 2 hours.
    • Your dose will depend on how you respond to the drug. It will also depend on how much levodopa/carbidopa you’ve been taking.
Child dosage (ages 0–17 years)

Sinemet has not been studied in children. It shouldn’t be used in children under the age of 18 years.

Senior dosage (ages 65 years and older)

There are no specific recommendations for senior dosing. Older adults may process drugs more slowly. A typical adult dose may cause levels of the drug to be higher than normal in older adults. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

Enteral suspension:

  • This drug comes in a 100 mL cassette. You should only use these cassettes one time each. They’re designed to run for the 16-hour period.  Don’t reuse the cassette or run it longer than 16 hours, even if some of the drug is left.  
  • You should disconnect the feeding tube after 16 hours and flush it with water.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

This drug comes with risks if you don’t take it as prescribed.

If you stop taking the drug suddenly or don’t take it at all

Your symptoms of Parkinson’s disease or parkinsonism may return or get worse. Stopping this drug suddenly may lead to neuroleptic malignant syndrome. You may have a fever, stiff muscles, and mental health issues. Your doctor should monitor you closely if you reduce your dose significantly or you stop taking this drug.

If you miss doses or don’t take the drug on schedule

Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.

If you take too much

You could have dangerous levels of the drug in your body. Symptoms can include:

  • fast heart rate
  • irregular heart rhythm
  • low blood pressure
  • hallucinations (seeing or hearing things that aren’t there)
  • confusion
  • muscle pain or weakness

If you think you’ve taken too much of the drug, call your doctor or local poison control center. If your symptoms are severe, call 9-1-1 or go to the nearest emergency room right away.

What to do if you miss a dose

Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.

How to tell if the drug is working

Your symptoms of Parkinson’s disease or parkinsonism should decrease.

This drug is used for long-term treatment.

You can take this drug with or without food

If this drug upsets your stomach, you can take it with a small, non-protein snack. High-protein foods decrease the absorption of this drug. Acceptable snack options include fruit or crackers.

Cutting or crushing your medication

You can cut or crush the immediate-release tablet.

Don’t crush or chew the extended-release tablet. You can break the extended-release tablet in half along the score line (the line down the center of the tablet).

Store this drug carefully

  • Store this drug at a room temperature of 77ºF (25ºC). You can store it between 59ºF and 86ºF (15ºC and 30ºC) for a short time.
  • Don’t store this medication in moist or damp areas, such as bathrooms.
  • Protect this medication from light.

A prescription for this medication is refillable

You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
  • Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Self-management

Take this drug with 6–8 ounces of water. Take this drug at least 30 minutes before eating or 1 hour after meals. This will increase absorption.

If this drug upsets your stomach, you can take it with a small non-protein snack. These include fruit or crackers. High-protein foods decrease the absorption of this drug. This means it won’t work as well.

Clinical monitoring

Your doctor will screen you for skin cancer while you take this drug. This monitoring involves:

  • Skin examinations. You and your doctor should regularly check for any changes to your skin.

You and your doctor should monitor certain health issues. This can help make sure you stay safe while you take this drug. These issues include:

  • kidney function
  • liver function
  • blood pressure
  • heart rate
  • inner eye pressure (if you have glaucoma)

Your diet

Eating a diet high in protein may cause your body to absorb less levodopa. This means that this drug may not work as well to treat your condition. Ask your doctor if you need to make any changes to your diet while you take this drug.

Insurance

Many insurance companies require a prior authorization for some forms of this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

What does the pill look like?

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How Much Does carbidopa-levodopa Cost?

Oral tablet

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Lowest price for carbidopa-levodopa

Membership warehouse $16.90
Kroger Pharmacy $17.00
Target (CVS) $17.35
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These prices represent the lowest priced national pharmacies for carbidopa-levodopa on GoodRx. They may be lower than your insurance.

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on December 18, 2015

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 other 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.
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