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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Entacapone
Generic Name
Entacapone
Active Ingredient
EntacaponeCategory
Aromatic Amino Acid [EPC]
Variants
13
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Entacapone, you must consult a qualified healthcare professional.
| 200 mg/1 | TABLET | ORAL | 33342-260 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 47335-007 |
| 200 mg/1 | TABLET | ORAL | 27241-049 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 50268-295 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 60687-188 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 65862-654 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 71610-247 |
| 200 mg/1 | TABLET, FILM COATED | ORAL | 0904-6822 |
| 200 mg/1 | TABLET | ORAL | 0615-8298 |
+ 1 more variants
Detailed information about Entacapone
Entacapone is a selective and reversible catechol-O-methyltransferase (COMT) inhibitor used as an adjunct to levodopa/carbidopa therapy in patients with Parkinson's disease who experience 'wearing-off' symptoms at the end of a dosing interval.
The standard adult dose of Entacapone is 200 mg taken orally with each dose of levodopa/carbidopa. Because Entacapone's primary function is to prevent the breakdown of levodopa, it must be present in the system at the same time as the levodopa.
Entacapone is not approved for use in pediatric patients. Parkinson's disease is exceptionally rare in children and adolescents, and the safety and efficacy of COMT inhibitors in this population have not been established. If a juvenile form of parkinsonism is suspected, specialized pediatric neurology consultation is mandatory.
For patients with renal impairment (kidney dysfunction), no specific dosage adjustment for Entacapone is typically required. Since only 10% of the drug is excreted via the kidneys, even moderate to severe renal disease does not significantly alter the plasma levels of the drug. However, patients on dialysis should be monitored closely for general tolerability.
Patients with hepatic impairment (liver disease) should be treated with extreme caution. The liver is the primary site of Entacapone metabolism and biliary excretion. In patients with cirrhosis or significant liver dysfunction, the area under the curve (AUC) and peak plasma levels (Cmax) of Entacapone can be nearly double those of healthy individuals. Healthcare providers may need to adjust the frequency of dosing or consider alternative therapies in severe cases of hepatic failure.
No specific age-related dosage adjustments are recommended for the elderly. However, older patients may be more susceptible to certain side effects of dopaminergic therapy, such as hallucinations, confusion, and orthostatic hypotension (a drop in blood pressure upon standing). Close monitoring for these adverse effects is essential in the geriatric population.
If you miss a dose of Entacapone, take it as soon as you remember, provided you are also taking your levodopa/carbidopa dose. If it is almost time for your next scheduled dose, skip the missed dose and return to your regular schedule. Do not 'double up' on Entacapone doses to make up for a missed one. Since Entacapone must be taken with levodopa, missing a dose may result in an earlier return of Parkinson's symptoms (the 'wearing-off' effect).
Symptoms of Entacapone overdose may include severe confusion, agitation, aggression, or extreme drowsiness. Because Entacapone increases the levels of levodopa, an overdose may also manifest as severe dyskinesia (uncontrolled movements) or significant hypotension.
In the event of a suspected overdose:
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking this medication without medical guidance, as sudden discontinuation can lead to a dangerous return of symptoms.
Because Entacapone increases the amount of levodopa that reaches the brain, many of its side effects are actually 'dopaminergic' in nature—meaning they are caused by increased dopamine activity.
Entacapone must only be used as an adjunct to levodopa/carbidopa. It has no therapeutic effect on its own and will not treat Parkinson's symptoms if taken without levodopa. Patients should be aware that because Entacapone increases the potency of levodopa, existing side effects of levodopa (like dyskinesia or hallucinations) may be intensified when starting this medication.
No FDA black box warnings for Entacapone. Unlike its predecessor, tolcapone, Entacapone has not been associated with a significant risk of acute explosive liver failure in the general population. However, safety precautions regarding other organ systems and behavioral changes remain paramount.
Entacapone is strictly prohibited in the following circumstances:
Entacapone is classified as Pregnancy Category C. This means that animal reproduction studies have shown an adverse effect on the fetus, but there are no adequate and well-controlled studies in humans. In animal studies, Entacapone was associated with reduced fetal body weights and increased fetal variations when given at doses much higher than the human therapeutic range.
Because Parkinson's disease typically affects older adults, pregnancy while taking Entacapone is rare. However, if a patient becomes pregnant, Entacapone should only be used if the potential benefit justifies the potential risk to the fetus. There is no data regarding its use in fertility treatments.
It is not known whether Entacapone is excreted in human breast milk. In animal studies (rats), Entacapone was found to be excreted in milk. Because many drugs are excreted in human milk and the potential for serious adverse reactions in nursing infants from Entacapone is unknown, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the drug to the mother.
Entacapone is a selective, reversible, and peripherally acting inhibitor of catechol-O-methyltransferase (COMT). In the presence of a decarboxylase inhibitor like carbidopa, COMT becomes the major metabolizing enzyme for levodopa. COMT catalyzes the transfer of a methyl group from S-adenosyl-L-methionine to the 3-hydroxy group of levodopa, forming 3-O-methyldopa (3-OMD). By blocking this enzyme, Entacapone prevents the formation of 3-OMD and leads to higher, more sustained plasma levels of levodopa. This allows for a more constant supply of levodopa to the brain, where it is converted to dopamine.
Entacapone's effect is dose-dependent. A 200 mg dose inhibits red blood cell COMT activity by approximately 65% at peak. The inhibition is reversible; as plasma levels of Entacapone fall, COMT activity returns to baseline. There is no evidence of tolerance developing to the COMT-inhibiting effects of Entacapone over time. Its primary pharmacodynamic effect is the extension of the elimination half-life of levodopa (usually by about 30-50%).
| Parameter | Value |
Common questions about Entacapone
Entacapone is primarily used as an add-on treatment for patients with Parkinson's disease who are already taking levodopa and carbidopa. Its specific purpose is to treat 'wearing-off' symptoms, which occur when the effects of Parkinson's medication fade before it is time for the next dose. By blocking an enzyme called COMT, Entacapone allows levodopa to stay in the bloodstream longer, providing more consistent symptom relief. It helps reduce 'off' time, where movement is difficult, and increases 'on' time, where mobility is improved. It is not a cure for Parkinson's and cannot be used by itself; it only works in combination with levodopa.
The most common side effects of Entacapone include involuntary movements known as dyskinesia, nausea, and a harmless change in urine color to brownish-orange. Because Entacapone increases the amount of dopamine in the brain, it can often worsen existing levodopa side effects like jerky movements or dizziness. Many patients also report gastrointestinal issues such as diarrhea or abdominal pain. Some people may experience tiredness or hallucinations, particularly if they are older. Most of these side effects are manageable by adjusting the dose of levodopa, so it is important to stay in close contact with your neurologist.
It is generally advised to avoid or strictly limit alcohol consumption while taking Entacapone. Alcohol can enhance the central nervous system depressant effects of the medication, leading to increased drowsiness, dizziness, and a higher risk of accidental falls. Furthermore, both alcohol and Parkinson's medications can lower blood pressure, which may cause you to feel faint or lightheaded when standing up. Combining the two can also increase the risk of confusion and impaired judgment. If you choose to drink, you should discuss it with your doctor to understand your specific risks. Always prioritize safety, especially if you are prone to balance issues.
Entacapone is classified as a Pregnancy Category C medication, meaning there is not enough human data to guarantee its safety during pregnancy. Animal studies have suggested that high doses could potentially harm a developing fetus, leading to lower birth weights or skeletal variations. Since Parkinson's disease usually affects individuals later in life, pregnancy is not common among users, but it can occur in cases of early-onset Parkinson's. If you are pregnant or planning to become pregnant, you must discuss the risks and benefits with your healthcare provider. They will help you decide if the benefits of maintaining mobility outweigh the potential risks to the baby. Breastfeeding is also generally discouraged as it is unknown if the drug passes into human milk.
Entacapone begins working very quickly, often within the first few doses, because it starts inhibiting the COMT enzyme almost immediately after absorption. Most patients will notice an increase in their 'on' time and a reduction in 'wearing-off' symptoms within the first one to two days of starting the medication. However, because your doctor may need to adjust your levodopa dose to prevent side effects like dyskinesia, it may take several weeks to find the optimal balance. Your healthcare provider will likely monitor your response closely during the first month. Consistent timing of your doses is key to seeing the full benefit of the medication. If you do not see improvement within a few weeks, consult your doctor.
No, you should never stop taking Entacapone suddenly without consulting your doctor first. Abruptly stopping Parkinson's medications can cause a severe and potentially life-threatening reaction known as Neuroleptic Malignant Syndrome or Parkinsonism-hyperpyrexia syndrome. This condition is characterized by a very high fever, extreme muscle rigidity, confusion, and changes in heart rate or blood pressure. Additionally, stopping the drug will cause your 'wearing-off' symptoms to return quickly, which can significantly impair your ability to move and perform daily tasks. If the medication needs to be discontinued, your doctor will provide a plan to taper the dose slowly. Always follow medical guidance for any changes to your treatment regimen.
If you miss a dose of Entacapone, you should take it as soon as you remember, but only if you are also taking your scheduled dose of levodopa/carbidopa. Since Entacapone must be in your system at the same time as levodopa to be effective, taking it by itself later may not provide much benefit. If it is almost time for your next dose, simply skip the missed dose and resume your regular schedule. Do not take two doses at once to make up for the one you missed, as this can increase the risk of side effects like severe dyskinesia or nausea. Keeping a medication log or using a pill organizer can help you stay on track with your frequent dosing schedule.
Weight gain is not a typical side effect of Entacapone; in fact, weight loss is more commonly reported. Weight loss associated with Entacapone is often linked to gastrointestinal side effects like persistent diarrhea or nausea, which can reduce appetite or nutrient absorption. In some cases, the increased involuntary movements (dyskinesia) caused by higher dopamine levels can also burn extra calories, leading to weight loss. If you notice a significant or rapid change in your weight while taking this medication, you should inform your healthcare provider. They can determine if the weight change is due to the medication or another underlying issue. Maintaining a balanced diet is important for managing Parkinson's symptoms effectively.
Entacapone can interact with several other types of medications, so a full review of your drug list by a pharmacist or doctor is essential. It should never be taken with non-selective MAO inhibitors like phenelzine, as this can cause dangerously high blood pressure. It can also interact with drugs that are broken down by the COMT enzyme, such as epinephrine, dopamine, or certain antidepressants, potentially causing heart palpitations or high blood pressure. Additionally, Entacapone can bind to iron supplements, so they must be taken several hours apart. Always tell your doctor about all prescriptions, over-the-counter drugs, and herbal supplements you are using. This ensures that your Parkinson's treatment remains both safe and effective.
Yes, Entacapone is available as a generic medication, which is typically more cost-effective than the brand-name version, Comtan. Generic versions are required by the FDA to have the same active ingredient, strength, dosage form, and route of administration as the brand-name drug. They must also prove bioequivalence, meaning they work in the body the same way. Most insurance plans cover the generic version of Entacapone. If you have concerns about switching between brand and generic, or between different generic manufacturers, you should discuss them with your pharmacist. Consistent medication quality is important for managing the precise timing required for Parkinson's disease therapy.
> Warning: Stop taking Entacapone and call your doctor immediately if you experience any of these serious adverse events.
With prolonged use, the most significant concern is the management of dyskinesias. As Parkinson's disease progresses, the 'therapeutic window' for dopamine narrows, making it harder to balance the benefits of mobility with the side effects of involuntary movements. Additionally, long-term use requires monitoring of liver function, although Entacapone is generally not as hepatotoxic as earlier COMT inhibitors like tolcapone.
No FDA black box warnings for Entacapone. However, it is vital to distinguish Entacapone from Tolcapone (another COMT inhibitor), which does carry a black box warning for liver failure. While Entacapone is much safer for the liver, clinicians still monitor liver enzymes in patients with pre-existing hepatic conditions.
Report any unusual symptoms, especially changes in mood, behavior, or bowel habits, to your healthcare provider immediately.
Entacapone can cause significant somnolence (sleepiness) and sudden 'sleep attacks' where a patient falls asleep without warning. Do not drive a car, operate heavy machinery, or engage in dangerous activities until you know how this medication affects you. If you experience a sleep attack, you must stop driving and inform your doctor immediately.
Alcohol should be avoided or strictly limited while taking Entacapone. Alcohol can increase the sedative effects of the medication, leading to extreme drowsiness, dizziness, and an increased risk of falls. It may also worsen orthostatic hypotension.
Do not stop taking Entacapone suddenly. Abruptly discontinuing Parkinson's medications can lead to a condition called Neuroleptic Malignant Syndrome (NMS) or a 'Parkinsonism-hyperpyrexia syndrome.' Symptoms include very high fever, extreme muscle stiffness, and rapid heart rate. If the drug must be stopped, it should be done under a doctor's supervision with a gradual tapering of the dose.
> Important: Discuss all your medical conditions, including history of liver disease, hypotension, or mental health issues, with your healthcare provider before starting Entacapone.
Combining these can cause increased heart rate, arrhythmias (irregular heartbeats), and excessive blood pressure changes.
Entacapone does not typically interfere with standard laboratory blood tests. However, it can cause a false positive or interference in tests measuring urinary catecholamines or their metabolites due to its chemical structure and its effect on dopamine metabolism. Always inform the lab and your doctor that you are taking a COMT inhibitor.
For each major interaction, the management strategy usually involves either avoiding the combination, adjusting the dose of the interacting drug, or increasing the frequency of clinical monitoring for adverse effects.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter cold medicines which may contain ingredients like phenylephrine that can interact with COMT inhibitors.
Conditions requiring a careful risk-benefit analysis include:
There is a potential for cross-sensitivity between Entacapone and Tolcapone. While they are different molecules, they belong to the same chemical class (nitro-catechols). If a patient had a severe skin reaction or immune-mediated response to one, the other should be used with extreme caution or avoided.
> Important: Your healthcare provider will evaluate your complete medical history, including liver health and past reactions to Parkinson's medications, before prescribing Entacapone.
A large percentage of patients taking Entacapone are over the age of 65. Clinical studies have shown that the pharmacokinetics of Entacapone are not significantly different in the elderly compared to younger adults. However, elderly patients are more susceptible to:
Monitoring should be more frequent in this age group, and levodopa doses may need more aggressive downward adjustment when Entacapone is added.
As previously noted, renal impairment does not significantly alter the pharmacokinetics of Entacapone. No dose adjustment is required for patients with mild, moderate, or severe renal failure. However, the levodopa component of the patient's regimen may require monitoring in severe renal disease.
This is a critical area for Entacapone. The drug's metabolism is slowed in patients with liver dysfunction. In those with mild to moderate hepatic impairment, the AUC can increase by 80% to 100%. Healthcare providers should exercise caution and may consider longer intervals between doses or a lower total daily dose in patients with liver disease.
> Important: Special populations, particularly the elderly and those with liver disease, require individualized medical assessment and frequent follow-up to ensure safety.
| Bioavailability | 35% (range 25-50%) |
| Protein Binding | 98% (primarily to albumin) |
| Half-life | 0.4 - 0.7 hours (terminal) |
| Tmax | 0.7 - 1.2 hours |
| Metabolism | Isomerization and Glucuronidation (UGT1A9) |
| Excretion | Fecal 90%, Renal 10% |
Entacapone belongs to the therapeutic class of Antiparkinson Agents, specifically the subclass of COMT Inhibitors. Related medications include Tolcapone (Tasmar) and Opicapone (Ongentys). Unlike Tolcapone, Entacapone acts almost exclusively in the periphery, which accounts for its improved safety profile regarding liver toxicity.