Entacapone (Oral)

Entacapone is used together with levodopa/carbidopa to treat the side effects caused by the withdrawal from medication in patients with Parkinson's disease.


Entacapone is a drug that is used together with levodopa/carbidopa in patients with Parkinson's disease. The drug combination is typically employed to tackle the end-of-dose effect in patients with this chronic condition.

Parkinson's disease is sometimes called shaking palsy'. It is a disease affecting the patient's central nervous system. The condition is thought to be caused when there is a shortage of the natural substance, dopamine in the areas of the brain that are responsible for speech and mobility. Entacapone works by increasing the longevity of the effects of levodopa. This is achieved through blocking an enzyme called COMT, which breaks down levodopa before it can reach the patient's brain. If the levels of dopamine in the brain are kept stable, the patient may have better control of their symptoms for longer periods, allowing them to enjoy less interference with daily activities.

In the US, entacapone is sold under the brand name Comtan in tablet form and on prescription from your GP.

Conditions treated

  • Parkinson's disease

Type of medicine

  • Tablet

Side effects

As well as the benefits it brings, entacapone sometimes causes side effects. You may not notice any of these unwanted effects at all, but if you do, you may need to see your medical practitioner for treatment.

If you notice any of the following effects, contact your GP immediately:

  • Feeling unusually tired or weak
  • Uncontrolled repetitive movements of the legs, arms, tongue, face or lips
  • Twitching
  • Twisting
  • Stiffness
  • Shortness of breath
  • Hallucinating
  • Painful or difficult urination
  • Pain
  • Muscle cramps
  • Side or lower back pain
  • Increase in body movements
  • Hyperactivity
  • Fever or chills
  • Cough or hoarseness
  • Confusion
  • Decrease or absence of body movements

Some effects caused by entacapone go away on their own, once your body gets used to the new drug. If the effects are especially annoying or persistent, ask your doctor for advice on how best to manage or prevent the effects or if you have any questions relating to them. These self-resolving effects include:

  • Unusual weak feeling
  • Unusual or unpleasant aftertaste
  • Insomnia
  • Tremor
  • Tightness of the chest
  • Increase in sweating
  • Stomach upset, discomfort, tenderness
  • Tiny, red skin spots
  • Sleepiness or unusual drowsiness
  • Restlessness
  • Flatulence
  • Nausea
  • Muscle weakness or pain
  • Loss of strength or energy
  • Irritability
  • Indigestion
  • Heartburn
  • Dry mouth
  • Dizziness
  • Difficult or labored breathing
  • Diarrhea
  • Constipation
  • Burning feeling in the stomach or chest
  • Bruising
  • Belching
  • Anxiety
  • Acid or sour stomach
  • Abdominal or stomach pain

The effects noted here are not necessarily all that may be experienced by patients taking entacapone. If you have any other effects, check with your doctor.


You should only take entacapone as directed by your medical practitioner. In order to gain the most benefit from the medicine, do not take more or less than you have been prescribed. Do not change the frequency of use of the medication or the length of the course. You may take entacapone with or without food.

The dose of entacapone that you are told to take will not be the same for everyone. You should stick to your GP's instructions or follow the directions on the product label. The information given below is based on the average dose rate for this drug. If your dose is not the same as this, do not alter it, unless your treating physician directs you to do so.

Your dose of this drug will depend on the strength of the tablets you are given. The quantity of the drug that you must take each day, the frequency of the dose, and the total length of your course will depend on your medical condition, your liver function, and also on how well your body responds to the medication.

Parkinson's disease oral tablets:

  • Adults: Take 200 mg with each dose of carbidopa and levodopa medication. This dose rate may be increased up to eight times per day to a total of 1600 mg daily as required.
  • Children: Follow your GP's instructions as regards use and dose.

If you forget to take your medication, take it as soon as you can. If it is nearly time for your next tablet, miss it out and revert to your usual medication schedule. Do not take twice the dose.

To gain the most benefit from this medicine, it is important that you use it regularly. Try to take your tablet(s) at the same time every day so that the levels of entacapone remain stable in your blood. Do not suddenly stop taking the drug, unless your GP tells you to. Abruptly stopping the drug can make your Parkinson's symptoms get a lot worse.

If you think that your condition is not getting any better or if you think that it is actually becoming worse, tell your doctor straight away.

If you have overdosed on entacapone, you may have breathing difficulties, or you may even pass out. In such circumstances, call 911 immediately.


Some medication should never be used in combination with other drugs, as to do so could cause a serious interaction. However, in some circumstances, it may be appropriate for your treatment to use two drugs together, even though an interaction may occur. In this case, your GP may decide to change your dose of one or both of the drugs. Be sure to notify your doctor of any prescription or over the counter medications that you are taking, including herbal or vitamin products.

It is not recommended to use entacapone with any of the drugs listed below. Your doctor may elect to treat you with a different drug or may change some of the other medication that you take instead.

  • Warfarin
  • Voriconazole
  • Venlafaxine
  • Tranylcypromine
  • Tolbutamide
  • Rosiglitazone
  • Procarbazine
  • Phenelzine
  • Pargyline
  • Norepinephrine
  • Nialamide
  • Nateglinide
  • Methylene Blue
  • Methyldopa
  • Losartan
  • Linezolid
  • Isoproterenol
  • Isoetharine
  • Isocarboxazid
  • Irbesartan
  • Iproniazid
  • Glyburide
  • Glipizide
  • Glimepiride
  • Furazolidone
  • Fluvastatin
  • Epinephrine
  • Dopamine
  • Dobutamine
  • Desipramine
  • Bitolterol
  • Apomorphine

Some medicines should not be used when using alcohol, eating certain foods or using tobacco. Before you begin taking entacapone, you should talk to your doctor about using this drug with particular foods, tobacco or alcohol.

Some existing or historical health conditions can affect how entacapone works. Be sure to tell your doctor about any other health problems you have experienced, especially those mentioned below.

You should not take entacapone if you have ever had any of the following conditions, as to do so could make these problems worse:

  • Psychosis (mental disorder)
  • Kidney disease
  • Dyskinesia (abnormal muscle movements)
  • Colitis (inflammation of the colon)

Entacapone should be used with caution in patients who have liver disease. The effects of the medicine could be amplified due to the slower rate of removal of the drug from the body.


Before you begin treatment with a new drug, you should weigh the benefits against the risks of doing so. Discuss the pros and cons of using entacapone with your doctor before you begin using it.

You must inform your GP if you have ever experienced any strange reactions to entacapone or to any other medicines. In addition, tell your medical practitioner if you are allergic to certain food groups, animal products, food colors, or food preservatives.

Pregnancy and breastfeeding

There is no research to show that using entacapone can harm the unborn baby. In addition, it is not known whether this drug passes from the mother into her breast milk. If you are pregnant or breastfeeding, you should discuss the ramifications of using entacapone as part of your Parkinson's treatment regimen. It may be considered advisable to find an alternative method of feeding your infant, while you are being treated with this drug.

Medical conditions

You must attend your GP clinic on a regular basis so that your doctor can monitor your progress and check that entacapone is not causing any side effects.

While you are using entacapone, you should not take some MAO inhibitors, including tranylcypromine and phenelzine.

You should not stop taking your prescribed dose of entacapone unless you are told to by your medical practitioner. If your GP does decide to take you off this drug, you will most likely be told to slowly cut down the dose you are taking, before ceasing altogether.

It is possible that entacapone may cause feelings of fatigue or dizziness. Some patients even find that they fall asleep unexpectedly whilst talking, eating, or driving. If you find that this medicine affects you in this way, avoid driving or undertaking any other form of activity that may be dangerous.

With this in mind, it is also not recommended that you take certain non-prescription medicines that may make you feel sleepy, including:

  • Antihistamines
  • Hay fever medication
  • Cough and cold medicines
  • Sedatives
  • Sleeping drugs
  • Analgesics
  • Narcotics
  • Dental anesthetics
  • Anticonvulsant medicines

Always ask your dentist or GP before using any of the products in the above list while you are also taking entacapone.

Some patients report feeling nauseous when they first begin using this drug. Tell your doctor or pharmacist if you are affected in this way, as there may be ways of managing this side effect.

Another side effect of entacapone is dizziness when rising from a prone or seated position. If you are affected in this way, try getting up more slowly and ask your GP for more advice.

Some people develop odd thoughts or begin to act strangely while using entacapone. You may experience feelings of depression and confusion, hallucinate, feel unusually excited, irritable or nervous, or you may even have suicidal thoughts. You may even find that you suddenly develop an unusual interest in gambling or in sex while you are taking this drug. If you are affected in this way, speak to your doctor straight away.

Some Parkinson's patients develop severe diarrhea following long-term use of this medication. If you find yourself affected in this way, you should not take any form of diarrhea medication without first asking your GP's advice. Some of the constituents of diarrhea medicines can make the problem last longer or make it worse. If this proves to be a consistent problem, you should discuss it with your doctor.

If you notice that your urine is very dark in color, if you have a fever, muscle spasms or cramps, stiffness or pain, or if you feel very weak or tired, this could be symptomatic of an ailment known as rhabdomyolysis. Speak to your GP urgently if you develop these symptoms.

Some people taking entacapone develop a condition called neuroleptic malignant syndrome. This is a serious condition that requires medical attention immediately. The symptoms of NMS include:

  • Very pale skin
  • Tiredness
  • Severe muscle stiffness
  • Loss of bladder control
  • Increased sweating
  • High or low blood pressure
  • High fever
  • Fast heartbeat
  • Difficulty breathing
  • Convulsions (seizures)

Patients who suffer from Parkinson's disease can be prone to developing skin cancers (melanoma). In the event that you discover any new moles or if existing moles change in colour or shape, tell your doctor immediately.

Entacapone can have the effect of making your urine turn orange or dark brown in color. This is not a cause for concern and is quite normal.

You must not take any other medication unless you have discussed it first with your doctor. This includes all non-prescription and prescribed drugs, vitamin and herbal preparations.

Never share your prescription of entacapone with anyone else.

You will be asked to attend your GP clinic or hospital specialist department for regular check-up appointments to make sure that the medication is working correctly and that it is not causing any unwanted side effects. You may also be asked to undergo liver function tests. Be sure that you keep all your appointments as directed by your doctor.


Your prescription of entacapone must be stored in its original container, away from moisture, heat, and direct sunlight. Do not freeze or refrigerate the tablets.

Be sure to place the medication well out of the reach of small children and pets. If a pet does consume any of your entacapone tablets, ask your vet for advice straight away.

Never keep unwanted or out of date medication, and do not use any tablets that appear to be damaged. Dispose of unwanted drugs carefully by placing them in a sealed bag and concealing it at the bottom of your trash can where children and pets cannot access it. Do not throw unused medicines down the toilet or drain where they could get into the environment and contaminate watercourses.


Entacapone is a drug that is used to treat people who are suffering from Parkinson's disease. The medication is used as part of a combination treatment with carbidopa and levodopa to treat the end-of-dose effects that Parkinson's patients sometimes suffer.

Entacapone is a very effective medication, but it does present a number of side effects and should not be used in patients with a history of certain medical conditions. There is also a wide range of drugs that should not be used with entacapone, because doing so could cause interactions to take place.

When attending progress check appointments with your GP, always mention any ill-effects that you have experienced while taking this drug.wqasz