Indications  

Comtan is a prescribed medication used alongside levodopa/carbidopa to treat patients with idiopathic Parkinson’s Disease who exhibit signs and symptoms of end-of-dose “wearing-off.” 

Classified as a catechol-O-methyltransferase (COMT) inhibitor, Comtan impedes the activity of the naturally occurring COMT enzyme responsible for levodopa breakdown. This mechanism extends the duration of levodopa’s effectiveness, preventing premature wearing off before the next dose. 

Uses and Dosage 

Before taking Comtan and with every prescription refill, thoroughly review its medication guide and patient information leaflet. Consult your doctor or pharmacist if you have any questions or concerns. 

Comtan is usually taken with every levodopa/carbidopa dose, up to 8 times daily. It can be taken with or without food, although taking it with food may aid in preventing nausea, a common side effect of entacapone. 

To achieve optimal results, adhere to a regular and precise dosing schedule as directed. Avoid exceeding or reducing the prescribed dosage or frequency without medical guidance. 

Keep taking Comtan as prescribed, even if you feel well. Consult your doctor before discontinuing its use, as abruptly stopping this medication can exacerbate Parkinson’s disease symptoms and have potential adverse effects. If needed, your doctor will likely taper the dosage gradually. 

Side Effects 

Listed below are the potential adverse effects that may arise from taking Comtan. Promptly notify your physician if any of them last or worsen. 

Common Side Effects 

• Dizziness or drowsiness 
• Nausea, vomiting, or stomach pain 
• Diarrhea 
• Dry mouth 
• Uncontrolled muscle movements 

Serious Side Effects 

• Agitation, confusion, or unusual thoughts or behavior 
• Hallucinations  
• Very stiff (rigid) muscles, high fever, excessive sweating, rapid or irregular heartbeats, tremors, feeling lightheaded 
• Severe or persistent diarrhea 
• Restless muscle movements in the eyes, tongue, jaw, or neck (or worsening of Parkinson’s symptoms) 
• Unexplained muscle pain, tenderness, or weakness, particularly when accompanied by fever, unusual fatigue, and dark urine 

Call your doctor immediately if you experience any of the above-listed severe side effects. 

The color of your urine may change to orange, red, brown, or black. This color change is typically harmless unless accompanied by muscle pain and unusual weakness. 

Allergic Reactions 

Severe allergic reactions to Comtan are uncommon; however, seek immediate medical attention if you experience symptoms such as: 

• Hives 
• Difficult breathing 
• Face, lips, tongue, or throat swelling 

This list does not contain all the potential side effects of Comtan. If you experience any unlisted effects, tell your doctor right away. 

Cautions 

Before starting treatment with Comtan, inform your doctor and pharmacist if you have any known hypersensitivities, especially to entacapone, any other medications, or any of the ingredients present in Comtan tablets. 

To ensure Comtan is safe for you, disclose to your physician your medical background, specifically if you have a history of: 

• Alcoholism 
• Liver problems 
• Low blood pressure 
• Mental/mood disorders (e.g., depression, schizophrenia) 
• Sleep disorders 

Potential interactions may occur between Comtan and certain MAO inhibitors, such as: 

• Isocarboxazid 
• Linezolid 
• Metaxalone 
• Methylene blue 
• Moclobemide 
• Phenelzine 
• Procarbazine 
• Tranylcypromine 

Certain MAO inhibitors (safinamide, selegiline, rasagiline) may be used with caution and close medical supervision. If you are currently taking rasagiline or selegiline for Parkinson’s disease, consult your doctor to determine whether you should continue their usage. 

To prevent potential drug interactions, inform your doctor and pharmacist about all your medicines, including prescription and over-the-counter drugs, other dietary supplements, and herbal products. 

Comtan can interfere with the effectiveness of other drugs by slowing down their removal from the body. Drugs like apomorphine, dobutamine, methyldopa, among others, may be affected. 

Taking Comtan with other drugs that induce drowsiness can intensify this effect. Consult your doctor before taking this medication alongside sleeping pills, narcotic pain medication, muscle relaxants, or medications for anxiety, depression, or seizures. 

The use of Comtan could result in unexpected daytime sleepiness, which may occur during regular activities like driving, eating, working, or talking. Even if you feel awake, you may doze off abruptly. Inform your doctor if you experience drowsiness or excessive daytime sleepiness. 

Comtan should only be taken if necessary during pregnancy. Consult with your doctor to evaluate the risks and benefits of this medication. 

The potential transfer of entacapone into breast milk and its impact on nursing infants is uncertain. Inform your physician if you are currently breastfeeding.