SIDE EFFECTS: Nausea, vomiting, diarrhea, unwanted/uncontrolled movements, increased sweating, drowsiness, tiredness, dry mouth, gas, and abdominal pain may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Lightheadedness or dizziness upon standing may also occur, especially during the first few weeks of treatment. To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication may develop serious side effects, but with frequent visits to your doctor, this risk can be minimized.

Your urine may turn brownish-orange. This effect is harmless.

Tell your doctor immediately if any of these unlikely but serious side effects occur: mental/mood changes (such as confusion, hallucinations), unusual urges (such as increased gambling, sexual urges), fever, muscle stiffness, persistent diarrhea.

Tell your doctor immediately if any of these rare but very serious side effects occur: easy bleeding/bruising, sore/painful muscles, muscle weakness, trouble breathing, pain with breathing.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the Comtan (entacapone) Side Effects Center for a complete guide to possible side effects »

PRECAUTIONS: Before taking entacapone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: alcoholism, liver problems, low blood pressure.

This drug may make you dizzy or drowsy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Avoid alcoholic beverages.

Older adults may be more sensitive to the side effects of this drug, especially drowsiness and confusion.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is not known whether this drug passes into breast milk. Consult your doctor before breast-feeding.