Medically reviewed by Drugs.com. Last updated on Mar 23, 2022.
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antiparkinsonian
Pharmacologic Class: Catechol-O-Methyltransferase Inhibitor
Uses for Comtan
Entacapone is used in combination with levodopa/carbidopa to treat end-of-dose "wearing off" effect in patients with Parkinson's disease, sometimes called shaking palsy. Parkinson's disease is a disorder of the central nervous system (brain and spinal cord).
Dopamine is a naturally occurring substance in the brain that helps provide control of movement and activities such as walking and talking. In patients with Parkinson's disease, there is not enough dopamine in some parts of the brain. Entacapone helps levodopa last longer by blocking a substance called COMT enzyme. This enzyme breaks down levodopa before it reaches the brain. When less levodopa is broken down, more is available to the brain. Increased availability of levodopa may lead to smoother and steadier levels of dopamine in the brain, which may provide better symptom control for longer periods each day. This may lead to improvement in daily activities.
This medicine is available only with your doctor's prescription.
Before using Comtan
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies have not been performed on the relationship of age to the effects of entacapone in the pediatric population. Safety and efficacy have not been established.
No information is available on the relationship of age to the effects of entacapone in geriatric patients.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
- Methylene Blue
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Colitis (inflammation of the colon) or
- Dyskinesia (abnormal muscle movements) or
- Kidney disease or
- Psychosis (mental disorder), or history of—Use with caution. May make these conditions worse.
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper use of Comtan
Take this medicine only as directed by your doctor, to help your condition as much as possible. Do not take more or less of it, and do not take it more or less often than your doctor ordered.
Take this medicine with or without food.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For Parkinson's disease:
- Adults—200 milligrams (mg) with each levodopa/carbidopa dose. Your doctor may increase your dose up to 8 times per day for a total dose of 1600 mg per day.
- Children—Use and dose must be determined by your doctor.
- For Parkinson's disease:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using Comtan
It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.
You should not use certain MAO inhibitors (such as phenelzine, tranylcypromine) while using this medicine.
Do not stop taking entacapone without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping completely.
This medicine may make you dizzy or drowsy. It may even cause you to fall asleep without warning while you drive, talk, or eat. Do not drive or do anything that could be dangerous until you know how this medicine affects you.
This medicine will add to the effects of other CNS depressants (medicines that make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds, sedatives, tranquilizers, or sleeping medicine, prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Check with your medical doctor or dentist before taking any of the above while you are taking this medicine.
It is possible that you may become nauseous, especially when you are first starting your medicine.
Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position. Getting up slowly may help. If you should have this problem, check with your doctor.
If you develop any unusual or strange thoughts and behavior while receiving this medicine, be sure to discuss it with your doctor. Other changes might be confusion, worsening of depression, visual hallucinations (seeing things that are not there), suicidal thoughts, and unusual excitement, nervousness, or irritability.
Some people who have used this medicine had unusual changes in their behavior. Talk with your doctor right away if you start having problems with gambling or an increased interest in sex while using this medicine.
This medicine may cause diarrhea, and in some cases it can be severe. It can occur months after starting this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. Diarrhea medicines may make the diarrhea worse or make it last longer. If you have any questions about this or if mild diarrhea continues or gets worse, check with your doctor.
Check with your doctor right away if you have dark-colored urine, fever, muscle cramps or spasms, muscle pain or stiffness, or unusual tiredness or weakness. These may be symptoms of a condition called rhabdomyolysis.
Check with your doctor right away if you are having convulsions (seizures), difficulty with breathing, a fast heartbeat, a high fever, high or low blood pressure, increased sweating, loss of bladder control, severe muscle stiffness, unusually pale skin, or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).
It is important that your doctor check your skin regularly for signs of a skin cancer called melanoma. If you notice any unusual red, brown, or black spots on your skin, talk to your doctor right away.
This medicine may cause your urine to turn brownish orange. This is normal and nothing to worry about.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Comtan side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
- Absence of or decrease in body movements
- increase in body movements
- seeing, hearing, or feeling things that are not there
- uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
- Cough or hoarseness
- fever or chills
- lower back or side pain
- painful or difficult urination
- muscle cramps
- shortness of breath
- unusual tiredness or weakness
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Abdominal or stomach pain
- Acid or sour stomach
- burning feeling in the chest or stomach
- difficult or labored breathing
- dry mouth
- loss of strength or energy
- muscle pain or weakness
- passing gas
- sleepiness or unusual drowsiness
- small, red spots on the skin
- stomach discomfort, upset, or tenderness
- sweating increased
- tightness in the chest
- trouble sleeping
- unusual or unpleasant (after) taste
- unusual weak feeling
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
More about Comtan (entacapone)
- Side effects
- Drug interactions
- Dosage information
- During pregnancy or Breastfeeding
- Reviews (6)
- Drug images
- Pricing & coupons
- Generic availability
- En español
- Drug class: dopaminergic antiparkinsonism agents
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.