Entacapone

Entacapone is a prescription medication used together with levodopa/carbidopa to help manage Parkinson’s disease. This guide explains the basics in plain language. It does not replace advice from your care team.

What is Entacapone?

Entacapone is a prescription medicine in the catechol-O-methyltransferase (COMT) inhibitor drug class. It is not used by itself. It is always taken along with levodopa/carbidopa.

Approved use in the United States:

• Used with levodopa/carbidopa to treat adults with Parkinson’s disease who have “wearing-off” episodes, meaning their symptoms return before the next levodopa dose is due

Available formulations and strengths:

• Entacapone tablets (Entacapone 200mg), taken by mouth
• Combination tablets that contain entacapone, levodopa, and carbidopa in one pill (available in several strength combinations)

The combination tablet and the entacapone-only tablet are not interchangeable. Each strength has its own detailed page with more information.

What is the Recommended Dosage of Entacapone?

Dosing is set by your prescriber and is closely tied to your levodopa/carbidopa schedule. Factors that may affect your plan include:

• Your levodopa dosing. Entacapone is taken with each levodopa/carbidopa dose, and the levodopa dose may need to be lowered after starting entacapone.
• Severity of symptoms and wearing-off pattern.
• Liver function. Entacapone is processed by the liver, so people with liver problems may need a lower dose or closer monitoring.
• Age. Older adults may be more sensitive to side effects.
• The product type. Entacapone alone and the combination tablet are dosed differently.

Kidney function does not usually require a dose change. Entacapone has not been established for use in children. Always follow the exact instructions from your neurologist or other prescribing specialist and your pharmacy label. Do not change your dose or schedule on your own.

How Entacapone Works

Levodopa is converted in the body into dopamine, a brain chemical that helps control movement. In Parkinson’s disease, dopamine levels are low. However, an enzyme called COMT breaks down levodopa before it can reach the brain.

Entacapone blocks this enzyme. This allows levodopa to last longer in the body, which may help reduce “off” time between doses.

Entacapone helps manage symptoms. It does not cure Parkinson’s disease and does not slow its progression.

Is a Prescription Required to Buy Entacapone Online?

Yes. In the United States, entacapone is a prescription-only medication. A licensed clinician must decide whether it is appropriate for you. This is usually a neurologist, ideally one who specializes in movement disorders.

If you buy medication online, use only licensed, verified pharmacies that require a valid prescription. Be cautious of websites that offer prescription medicines without one. Counterfeit or improperly stored products may contain the wrong ingredient or the wrong amount. Products from unknown sources or made for animals are not safe substitutes.

Side Effects of Entacapone

Common Side Effects

Many side effects relate to increased levodopa effect. They may include:

• Involuntary movements (dyskinesia), especially early in treatment
• Nausea
• Diarrhea
• Abdominal pain
• Constipation or dry mouth
• Dizziness
• Fatigue
• Harmless brownish-orange discoloration of urine

Tell your clinician if these effects continue or bother you. Your levodopa dose may need adjusting.

Serious Side Effects

These are less common but need prompt attention:

• Hallucinations, confusion, or new paranoia
• Fainting or severe dizziness when standing up
• Severe or persistent diarrhea, which may appear weeks or months after starting
• Sudden episodes of falling asleep during daily activities
• New, unusual urges, such as gambling, overeating, or compulsive behaviors
• Signs of liver problems, such as yellowing of the skin or eyes, dark urine beyond the usual color change, or severe stomach pain
• High fever, severe muscle stiffness, and confusion, especially after stopping or lowering the dose suddenly
• Possible worsening of dyskinesia

Seek emergency medical care for fainting, trouble breathing, chest pain, signs of an allergic reaction such as facial swelling or hives, or thoughts of self-harm.

Drug Interactions

Some medications and substances can raise the risk of side effects or change how entacapone works. Examples include:

• Levodopa/carbidopa, the required partner medicine, which often needs dose adjustment
• Non-selective MAO inhibitors, such as phenelzine and tranylcypromine, which should not be used with entacapone
• Selegiline and rasagiline (MAO-B inhibitors), which may be used together under close supervision, with dose limits for selegiline
• Medicines broken down by the same enzymes, such as apomorphine, isoproterenol, epinephrine, norepinephrine, dopamine, dobutamine, and methyldopa, which may cause faster heart rate or blood pressure changes
• Iron supplements, which can bind to entacapone in the gut
• Sedating medicines, including sleep aids, sedatives, and alcohol, which may increase drowsiness or dizziness
• Certain antipsychotic and anti-nausea medicines, which may work against Parkinson’s treatment

Over-the-counter products to review with a pharmacist include cough and cold products, decongestants, antihistamines, and sleep aids. Supplements and herbal products should also be reviewed, especially iron, multivitamins with iron, and products that cause drowsiness.

Give your licensed medical specialist a complete list of everything you take, including prescriptions, OTC medicines, vitamins, and herbal products.

Safety & Important Considerations

• Liver disease: Entacapone is processed by the liver. Dose adjustment and monitoring may be needed. Rare liver injury has been reported with a related medicine (tolcapone), so tell your clinician about any liver history.
• Kidney disease: Dose changes are usually not needed.
• Pregnancy: Human data are limited. Talk with your clinician before taking entacapone if you are pregnant or planning pregnancy.
• Breastfeeding: It is not known whether entacapone passes into breast milk. Your clinician can help you weigh the options.
• Children: Safety and effectiveness have not been established.
• Older adults: Dizziness, confusion, hallucinations, and falls may be more likely, so closer monitoring is often needed.
• Other conditions: Tell your clinician if you have low blood pressure, psychiatric illness, a history of compulsive behaviors, or bile duct or gallbladder problems.
• Do not stop suddenly. Abrupt discontinuation may worsen symptoms or, rarely, cause a serious reaction.
• Driving and machinery: Be careful until you know how the medicine affects you, since sudden sleepiness has been reported.
• Monitoring: Your clinician may check movement symptoms, blood pressure, mood, thinking, liver tests, and weight over time.
• Other: Some studies have raised questions about a possible link between Parkinson’s treatments and skin cancer (melanoma). Regular skin checks are often recommended.

Who This Medication Is For

Entacapone may be prescribed to adults with Parkinson’s disease who take levodopa/carbidopa and notice symptoms returning before their next dose. It is not a first-line treatment for early Parkinson’s disease and is not used without levodopa. Your specialist decides if it is suitable based on your health history and other treatments.

Who Should Not Take Entacapone

Entacapone should not be used by:

• People who are allergic to entacapone or any ingredient in the product
• People taking non-selective MAO inhibitors (such as phenelzine or tranylcypromine)

Use with extra caution, and only with clinician guidance, if you have liver disease, low blood pressure, severe dyskinesia, psychosis or other mental health conditions, or a history of neuroleptic malignant syndrome. Use is also a concern if you are pregnant or breastfeeding, or if you are an older adult.

What to Do If You Miss a Dose

• Entacapone is taken with each levodopa/carbidopa dose, so a missed entacapone dose is often handled together with the levodopa dose.
• If you remember soon after, take it as directed by your clinician. If it is nearly time for your next dose, skip the missed one and return to your regular schedule.
• Never take a double dose to make up for a missed one.
• If you are unsure how to handle a missed dose, contact your licensed medical specialist or pharmacist.

Related medications to Entacapone

Other medicines may be used depending on the situation:

• Other COMT inhibitors: opicapone and tolcapone (tolcapone requires special liver monitoring)
• MAO-B inhibitors: rasagiline, selegiline, safinamide
• Dopamine agonists: pramipexole, ropinirole, rotigotine
• Others: amantadine, extended-release levodopa products, and anticholinergic medicines

Each option has its own benefits and risks. Never switch or stop treatment without consulting your specialist.

Storage Instructions

• Store at room temperature, about 68°F to 77°F (20°C to 25°C), unless the label says otherwise.
• Keep in a tightly closed container, away from moisture, heat, and direct light. Avoid storing in a bathroom.
• Keep all medicines out of reach and sight of children and pets.
• Dispose of expired or unused medicine through a pharmacy take-back program when possible.

Disclaimer:

This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Patients must consult a licensed neurologist (or other relevant medical specialist, depending on the condition being treated) before starting, changing, or stopping treatment. Treatment decisions must be based on a full clinical evaluation by a qualified specialist.