Entacapone | Side Effects, Dosage, Uses & More

Generic Name:

entacapone, Oral tablet

All Brands

  • Comtan
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Highlights for entacapone

Oral tablet
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Entacapone is used to treat Parkinson’s disease with the drugs levodopa and carbidopa. As your disease progresses, levodopa and carbidopa don’t work as well and you start having end-of-dose “wearing off” symptoms of the disease.  Entacapone can help treat these symptoms.

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This drug comes in the form of a tablet you take by mouth.

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Entacapone is available as a brand-name drug called Comtan. It’s also available as a generic drug.

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More common side effects of taking this drug include movements you can’t control, brownish-orange urine, diarrhea, nausea, muscle spasms, stomach pain, vomiting, and dry mouth.

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In some cases, entacapone can cause severe side effects. This includes an increased risk for drowsiness and falling asleep suddenly. You should use caution when driving, using machinery, or doing activities with a risk of falling during treatment with this drug. 

IMPORTANT INFORMATION

Sleep effects

Entacapone may increase your risk for drowsiness and falling asleep suddenly. You should use caution when driving, using machinery, or doing activities with a risk of falling during treatment with this drug. If you feel drowsy or fall asleep suddenly while taking this drug, don’t do these activities. Tell your doctor about your symptoms right away.

Stopping the drug suddenly

Don’t stop taking this drug without talking to your doctor. If you need to stop treatment with this drug, your doctor will slowly decrease your dose over time. Stopping this drug suddenly may cause your Parkinson’s disease symptoms to come back.

Drug features

Entacapone is a prescription drug. It’s available as an oral tablet.

Entacapone 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. Talk to your doctor to see if the generic version will work for you.

Entacapone should be used as part of combination therapy with other medications for Parkinson’s disease. These drugs include levodopa and carbidopa.

Why it's used

Entacapone is used to treat Parkinson’s disease. It’s given with the other drugs levodopa and carbidopa to treat the end-of-dose “wearing off” symptoms of the disease.

How it works

Entacapone belongs to a class of drugs called catechol O-methyltransferase (COMT) inhibitors.

More Details

How it works

Entacapone belongs to a class of drugs called catechol O-methyltransferase (COMT) inhibitors. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

Entacapone helps other drugs work better to treat Parkinson’s disease. It does this by allowing more of the medications levodopa and carbidopa to reach your brain.

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entacapone Side Effects

Oral tablet

More Common Side Effects

Some of the more common side effects of entacapone include:

  • movements you can't control

  • brownish-orange urine

  • diarrhea

  • nausea

  • muscle spasms

  • stomach pain

  • vomiting

  • dry mouth

Pharmacist's Advice
Healthline Pharmacist Editorial Team

Entacapone may cause drowsiness.

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.
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entacapone May Interact with Other Medications

Oral tablet

Entacapone 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 effects from entacapone. You may have slowed reflexes, poor judgment, and sleepiness. This can be dangerous. If you drink alcohol, talk to your doctor.

Medications that might interact with this drug

Blood-thinning drugs

Entacapone may increase the amount of certain blood-thinning drugs in your body.  This raises your risk of bleeding. Your doctor should monitor your INR and signs of bleeding more closely during treatment with these drugs. Examples of these drugs include:

  • warfarin

Depression drugs

Both entacapone and certain depression drugs called monoamine oxidase inhibitors (MAOIs) increase the levels of chemicals, catecholamines, in your body.  Taking these drugs together may cause side effects such as insomnia (trouble sleeping) or constant drowsiness, dizziness, lightheadedness, and orthostatic hypotension (a sudden drop in blood pressure when getting up from a sitting or lying down position). Examples of these drugs include:

  • procarbazine
  • tranylcypromine
  • phenelzine

Heart rate and blood pressure drugs

Taking certain heart rate and blood pressure drugs with entacapone can increase the levels of your heart rate and blood pressure drugs. This may increase your risk of side effects, such as a fast heart rate, changes in heart rhythm, and large changes in blood pressure. Examples of these drugs include:

  • isoproterenol
  • epinephrine
  • norepinephrine
  • dopamine
  • dobutamine
  • methyldopa

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.

People with liver disease

If you have liver disease, your body may not be able to process this drug well. This can cause this drug to build up in your body. This can increase your risk of side effects. Ask your doctor whether this drug is safe for you.

Pregnant women

Entacapone 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.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should only be used if the potential benefit justifies the potential risk to the fetus.

Women who are breast-feeding

It isn’t known if entacapone passes into breast milk. If it does, it may cause side effects in a child who is breast-fed.

Talk to your doctor if you breast-feed your child. You may need to decide whether to stop breast-feeding or stop taking this medication.

For seniors

Older adults may process drugs more slowly. A normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

For children

It hasn’t been confirmed that entacapone is safe and effective for use in people younger than 18 years.

Allergies

Entacapone can cause a severe allergic reaction. Symptoms can include: 

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

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

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How to Take entacapone (Dosage)

Oral tablet

What are you taking this medication for?

Parkinson's Disease

Brand: Comtan

Form: Oral tablet
Strengths: 200 mg

Generic: Entacapone

Form: Oral tablet
Strengths: 200 mg
Adult dosage (ages 18–64 years)

The recommended dose is 200 mg taken by mouth up to a maximum of 8 times per day. This drug is taken with levodopa and carbidopa.

Child dosage (ages 0–17 years)

This medicine hasn’t been studied in children and shouldn’t be used in children younger than 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 normal adult dose may cause levels of this drug to be higher than normal in your body. If you’re a senior, you may need a lower dose or a different schedule.

Warnings

Don’t stop taking this drug suddenly. If you need to stop treatment with this drug, your doctor will slowly decrease your dose over time. Stopping this drug suddenly may cause your Parkinson’s disease symptoms to come back.

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

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

If you stop taking the drug suddenly

Don’t stop taking this drug suddenly. If you need to stop treatment with this drug, your doctor will slowly decrease your dose over time. Stopping this drug suddenly may cause your Parkinson’s disease symptoms to come back. These symptoms may be worse than you previously had.

If you don’t take it at all

If you don’t take entacapone, your symptoms of Parkinson’s disease may return or worsen.  

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. Taking too much could even be fatal (cause death). Symptoms of an overdose can include:

  • confusion
  • decreased awareness
  • discolorations of your skin, tongue, and urine
  • restlessness
  • agitation
  • aggression
  • coma (being unconscious for a long time)

If you think you’ve taken too much of this 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 should get better if entacapone is working.

Entacapone is used for long-term treatment.

Important considerations for taking this drug

Store this drug carefully

  • Store entacapone at room temperature. Keep it at 77ºF (25ºC).
  • If needed, this drug can be stored briefly between 59ºF and 86ºF (15ºC and 30ºC).
  • Don’t store this medication in moist or damp areas, such as bathrooms.

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. When flying, never put it into a checked bag. Keep it 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.

Clinical monitoring

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:

  • Liver function. Your doctor may do blood tests to check how well your liver is working. If your liver isn’t working well, your doctor may decide to lower your dose of this drug.
  • Skin cancer. You and your doctor should check your skin for any changes.

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 entacapone Cost?

Oral tablet

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Lowest price for entacapone

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These prices represent the lowest priced national pharmacies for entacapone 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 October 21, 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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