1 What is Comtan?

Brand: Comtan

Generic: Entacapone

Brand name:


Entacapone is a selective, reversible catechol-O-methyl transferase (COMT) inhibitor for the treatment of Parkinson's disease.

Parkinson's disease is a disorder of the central nervous system wherein there dopamine is lacking in certain areas of the brain manifested as a jerky involuntary movement.

This drug increases the levels of dopamine which is a naturally occurring substance in the brain that helps provide control of movement and activities such as walking and talking.

This drug works by helping levodopa last longer by blocking a substance called COMT enzyme. This may result in improvement in daily activities. This drug requires a prescription.

2 What to Know Before Using

Before taking this drug, the risks and benefits for your body should be discussed with your healthcare provider.

Inform your healthcare provider for any allergic reactions to these drugs or any other drugs, foods, dyes, preservatives, or animals.

Carefully read the label of non-prescription drugs for any possible allergic reaction or contraindications.

Studies in children on the correlation of age to the effects of entacapone have not been performed while safety and efficacy have not been established.

Studies in the elderly regarding the relationship of age to the effects of entacapone are still unavailable. Adverse effects have been reported in animal studies but there are studies in pregnant women or animals are still inadequate.

Infant risk is still undetermined when taking this drug during breastfeeding. Discuss with your healthcare professional about the risks and benefits of this drug before breastfeeding.

Drugs should not be taken together to prevent any interactions but in necessary cases inquire your healthcare provider regarding the adjustments in dosage or any other necessary precautions to prevent any unwanted side effects.

Inform your healthcare professional if you are taking any other drugs such as:

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

Intake of specific food or using alcohol or tobacco with this drug is associated with an increased risk of certain side effects.

Your healthcare professional can give you special instructions about the use of food, alcohol, or tobacco.

Inform your healthcare provider for any other medical problems such as colitis, dyskinesia, psychosis, kidney or liver diseases.

3 Proper Usage

This drug must be taken exactly as directed by your healthcare professional. To prevent any side effects, take this drug exactly as directed on the label or as prescribed by your healthcare professional.

Follow the instructions on the label or as directed by your healthcare professional. Take this drug with or without food. The dose of this drug will be variable for different patients.

The directions on the label or the prescription by your healthcare professional should be followed. The dosage of this drug you take depends on the medical problem for which you are using this drug.

Adults with Parkinson's disease are given 200 milligrams (mg) with each levodopa/carbidopa dose. Your healthcare professional may increase your dose up to 8 times per day for a total dose of 1600 mg per day.

Use and dose in children must be determined by your healthcare professional. A missed dose should be taken as soon as possible. However, skip the missed dose and go back to your regular dosing schedule if it is almost time for your next dose.

Store the drug in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing. Keep out of the reach of children.

Dispose any outdated or expired drugs and ask your healthcare professional for the proper disposal of the drugs. 

4 Precautions to Take

Your health care provider should closely monitor the effectiveness of this drug as well as check for unwanted effects.

Use of certain MAO inhibitors such as phenelzine and tranylcypromine is not recommended while taking this drug. Check with your healthcare professional before you stop taking entacapone.

Your healthcare professional may slowly taper the amount you are taking before stopping completely.

This drug may cause dizziness and drowsiness, or even cause you to fall asleep without warning while you drive, talk, or eat. Do not drive or do anything that could be dangerous after taking this drug.

This drug potentiates the effects of other CNS depressants such as antihistamines or drug for hay fever, other allergies, or colds, sedatives, tranquilizers, or sleeping drug, prescription pain drug or narcotics, a drug for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics.

Check with your medical health care professional or dentist before taking any of the above while you are taking this drug. This drug may cause nausea, dizziness, lightheadedness, or fainting.

Consult with your healthcare professional if you experience these symptoms.

Discuss it with your healthcare professional if you develop any unusual or strange thoughts and behavior, confusion, worsening of depression, visual hallucinations, suicidal thoughts, and unusual excitement, nervousness, or irritability while taking this drug.

If you start having problems with gambling or an increased interest in sex while using this drug, consult with your healthcare professional immediately.

This drug may cause diarrhea which can occur months after starting this drug. Consult with your healthcare professional before taking anti-diarrhea drugs as this may make the diarrhea worse or make it last longer.

Seek advice from your healthcare professional immediately if you symptoms of rhabdomyolysis such as dark-colored urine, fever, muscle cramps or spasms, muscle pain or stiffness, or unusual tiredness or weakness.

Check with your healthcare professional immediately if you have symptoms of a neuroleptic malignant syndrome such as convulsions, 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.

If you notice any unusual red, brown, or black spots on your skin, talk to your healthcare professional right away. This drug may cause your urine to turn brownish orange.

This is normal and nothing to worry about. Consult with your healthcare professional before taking any other prescription or nonprescription drugs, and herbal or vitamin supplements.

5 Potential Side Effects

Side effects may vary for each individual and prompt medical attention should be given if they occur. Consult with your healthcare professional immediately if you experience any unusual symptoms.

Some side effects may occur that usually do not need medical attention. As your body adjusts to the medicine, the side effects will slowly disappear.

Ask your healthcare professional about ways to prevent or reduce some of these side effects.

If any of the following side effects persists or are inconvenient, or if you notice any other effects, or if you have any questions about them, consult with your health care professional.

Report any side effects to the FDA hotline at 1-800-FDA-1088.

6 Related Clinical Trials