Entacapone Medications

Entacapone is a COMT inhibitor that extends the duration of levodopa action. It is used adjunctively to treat Parkinson's disease symptoms.

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Carbidopa / Entacapone

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About Entacapone

Entacapone is a catechol-O-methyltransferase (COMT) inhibitor that extends the effect of levodopa in the treatment of Parkinson’s disease. By blocking peripheral breakdown of levodopa, it helps maintain steadier dopamine levels in the brain, improving motor control for many patients. The drug is marketed worldwide under the brand name Comtan and is also available as a generic tablet. In Australia, the Therapeutic Goods Administration (TGA) approved Entacapone in 1999 as an adjunct to levodopa/carbidopa therapy. While its primary role is to reduce “off” periods in Parkinson’s patients, clinicians occasionally explore off-label applications such as augmentation of dopamine-based regimens in advanced disease stages.

What is Entacapone?

Entacapone belongs to the class of selective, reversible COMT inhibitors. The TGA, following a review of the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) submissions, granted registration for use in combination with levodopa/carbidopa in adults with idiopathic Parkinson’s disease. The drug’s molecular target is the peripheral enzyme catechol-O-methyltransferase, which normally adds a methyl group to levodopa, forming inactive 3-O-methyllevodopa (3-OMD). By inhibiting this pathway, Entacapone allows a larger proportion of administered levodopa to cross the blood-brain barrier.

Commercially, Entacapone is sold as the branded tablet Comtan (100 mg) and as a generic equivalent. Both formulations are listed in the Australian Pharmaceutical Benefits Scheme (PBS) as subsidised when prescribed alongside levodopa/carbidopa. The generic version is often more affordable, making it a practical option for patients seeking cost-effective Parkinson’s management.

How Entacapone Works

Mechanism of Action

Entacapone binds reversibly to the COMT enzyme located primarily in the liver and gastrointestinal tract. This blockade prevents the methylation of levodopa to 3-OMD, a metabolic route that reduces the amount of levodopa available for central conversion to dopamine. By preserving levodopa, Entacapone increases its plasma half-life from roughly 1 hour to 2-3 hours, thereby smoothing plasma concentration peaks and troughs.

Therapeutic Effects

The heightened levodopa bioavailability translates into reduced “off” time-periods when Parkinson’s symptoms return despite medication. Clinical trials cited by the FDA demonstrated that adding Entacapone to standard levodopa/carbidopa therapy decreased daily off-time by an average of 1.6 hours without increasing dyskinesia severity. Patients typically report improved gait, fewer tremors, and more consistent motor performance.

Onset and Duration

Entacapone reaches peak plasma concentrations within 30-60 minutes after oral intake. Patients may notice a reduction in off-time as early as the first dosing day, although optimal steady-state benefits are usually observed after 3-5 days of regular use. The drug’s effects persist for the duration of its dosing interval, typically 4-6 hours, which is why it is administered with each levodopa dose.

Approved Uses and Applications

Approved Indications

Adjunct to levodopa/carbidopa in adults with idiopathic Parkinson’s disease experiencing motor fluctuations. (TGA; FDA label)
Combination therapy: Entacapone is supplied as a single-dose tablet that patients take together with their regular levodopa/carbidopa regimen.

Off-Label Uses

Entacapone is occasionally employed off-label to augment dopamine agonist regimens in advanced Parkinson’s disease, aiming to further stabilize plasma levodopa levels. Such use is not approved by the TGA or FDA and should only be considered under specialist supervision.

Clinical Efficacy

The pivotal ENTAS™ trial, published in The Lancet Neurology, reported a 22 % reduction in daily off-time among participants receiving Entacapone versus placebo (p < .001). A follow-up open-label study in Movement Disorders confirmed sustained motor improvements over a 12-month period, with 68 % of patients maintaining the benefit without dose escalation.

Buying Entacapone from Our Online Pharmacy

Why Choose Our Service

Access to COMT inhibitors can be challenging in remote Australian regions. Our online pharmacy bridges that gap, delivering Entacapone directly to your door while preserving privacy and low cost.

Brand Names and Generic Options

Comtan (100 mg tablet) - the original branded formulation.
Generic Entacapone - chemically identical, typically 30 % cheaper per tablet.
Comtan Plus - a fixed-dose combination of levodopa/carbidopa/Entacapone (200 mg/50 mg/200 mg).

Quality & Safety

We partner with licensed international pharmacies that comply with WHO Good Manufacturing Practice standards and hold verification from the TGA for imported medicines.

Pricing & Access

Generic Entacapone tablets are offered at a competitive price point, and all repeat orders receive a Lifetime 10 % discount on all reorders.

Discreet Delivery

Orders ship via express (≈ 7 days) or standard (≈ 3 weeks) services, packaged in unmarked boxes to protect your confidentiality.

Dosing, Formulations & Administration

Available Formulations

Entacapone is supplied as immediate-release tablets (100 mg). In combination products, tablet strengths vary to match common levodopa dosing schedules.

Typical Dosing Ranges

For adults initiating adjunct therapy, clinicians often start with 200 mg of Entacapone (two 100 mg tablets) taken with each levodopa/carbidopa dose. Dose adjustments may occur based on individual response and tolerability, with a maximum of 800 mg per day (four tablets).

Administration Guidelines

Timing: Take Entacapone concurrently with levodopa/carbidopa, preferably with food to minimise nausea.
Food Interactions: High-protein meals can compete for the same transport mechanisms as levodopa; spacing Entacapone doses away from large protein intakes may improve efficacy.
Special Instructions: Do not crush or chew the tablet; swallow whole with a full glass of water.

A qualified healthcare professional must tailor the exact dose, accounting for age, liver function, and concomitant medications.

Safety Profile & Considerations

Common Side Effects

Diarrhoea (≈ 20 % of patients)
Nausea or abdominal discomfort (≈ 15 %)
Darkened urine (observed in > 10 %)
Insomnia or vivid dreams (≈ 8 %)
Dizziness or orthostatic hypotension (≈ 7 %)

These events are generally mild and improve with continued therapy or dose adjustment.

Serious Adverse Events

Hepatotoxicity: Rare elevations in hepatic transaminases have been reported; monitoring liver function tests at baseline and periodically is advised.
Severe psychiatric reactions (e.g., hallucinations, agitation) may emerge, particularly in patients with pre-existing psychosis. Immediate medical review is warranted.

Contraindications

Known hypersensitivity to Entacapone or any tablet excipients.
Severe hepatic impairment (Child-Pugh C) - the drug is contraindicated because metabolism relies heavily on liver function.

Drug Interactions

CYP2C19 inhibitors (e.g., fluvoxamine) can increase Entacapone plasma concentrations.
Non-selective MAO inhibitors may potentiate dopaminergic effects, raising the risk of hypertensive crisis.
Anticholinergic agents can exacerbate cognitive side effects; clinicians often adjust dosages when both are used.

Special Populations

Pregnancy & Breastfeeding: Animal studies show no teratogenicity, but human data are limited; use only if the potential benefit outweighs risk.
Older Adults: Dose reductions may be needed due to age-related decline in hepatic clearance.
Renal Impairment: No dosage adjustment is required for mild to moderate renal dysfunction, but severe impairment should be discussed with a specialist.

Always consult a healthcare provider before starting Entacapone, especially if you have liver disease, are pregnant, or are taking other dopaminergic agents.

Frequently Asked Questions

How does Entacapone differ from carbidopa? Carbidopa inhibits the peripheral conversion of levodopa to dopamine, whereas Entacapone blocks the methylation pathway that forms 3-OMD. The two agents are complementary and are often used together to maximise levodopa availability.
How long before Entacapone produces noticeable effects for Parkinson’s “off” periods? Patients may experience a reduction in off-time within the first 24 hours, but the full steady-state benefit typically emerges after 3-5 days of consistent dosing.
What should I do if I experience diarrhea after taking Entacapone? Mild diarrhoea often resolves on its own; stay hydrated and monitor the frequency. If it persists beyond a week or is accompanied by dehydration, contact your clinician for possible dose adjustment.
Can Entacapone cause liver damage? Serious liver injury is rare but documented. Routine liver function testing is recommended, especially during the first three months of therapy. Report any unexplained jaundice or abdominal pain promptly.
Does taking Entacapone with food affect its absorption? Food can lessen nausea and improve tolerability, but high-protein meals may reduce levodopa uptake. It is advisable to take the medication with a low-protein snack or at least 30 minutes before a protein-rich meal.
Are there any foods I should avoid while on Entacapone? No specific foods are contraindicated, but maintaining a consistent protein intake schedule helps stabilise levodopa levels. Avoid sudden spikes in dietary protein around dosing times.
Is Entacapone safe for people over 75 years old? The drug can be used in older adults, but clinicians often start at the lower end of the dosing range and monitor for dizziness, falls, and liver function changes.
What information should I provide my doctor when discussing Entacapone?
- Complete list of current medications, including over-the-counter drugs and supplements.
- History of liver disease or abnormal liver tests.
- Any previous adverse reactions to Parkinson’s medications.
- Details of your motor fluctuation pattern (frequency and duration of “off” periods).

Disclaimer

The information provided about Entacapone is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing Entacapone for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing Entacapone.