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Tasmar Side Effects

Generic Name: tolcapone

Note: This document contains side effect information about tolcapone. Some of the dosage forms listed on this page may not apply to the brand name Tasmar.

In Summary

Common side effects of Tasmar include: diarrhea, dyskinesia, insomnia, nausea, orthostatic hypotension, vomiting, confusion, dizziness, dystonia, headache, muscle cramps, anorexia, and increased dream activity. Other side effects include: syncope, abdominal pain, constipation, falling, fatigue, diaphoresis, urine discoloration, and xerostomia. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to tolcapone: oral tablet

Along with its needed effects, tolcapone (the active ingredient contained in Tasmar) 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 while taking tolcapone:

Incidence not known
  • Dark urine
  • itching
  • light-colored stools
  • loss of appetite
  • nausea (continuing)
  • tenderness in upper right part of abdomen
  • unusual drowsiness, dullness, or feeling sluggish
  • unusual tiredness or weakness
  • yellow eyes or skin

Check with your doctor as soon as possible if any of the following side effects occur while taking tolcapone:

More common Less common
  • Absence of or decrease in body movement
  • blood in urine
  • chest pain
  • chills
  • confusion
  • falling
  • general feeling of discomfort or illness
  • hyperactivity
  • loss of balance control
  • muscle pain
  • troubled breathing
  • Agitation
  • bloody or cloudy urine
  • burning of feet
  • burning, prickling, or tingling sensations
  • chest discomfort
  • difficult or painful urination
  • difficulty in thinking or concentrating
  • frequent urge to urinate
  • irritability
  • joint pain, redness, or swelling
  • low blood pressure
  • muscle cramps
  • neck pain
  • stiffness

Some side effects of tolcapone 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:

More common
  • Constipation
  • dryness of mouth
  • excessive dreaming
  • increased sweating
Less common
  • Bleeding
  • difficulty in sleeping
  • excessive muscle tone
  • fever
  • heartburn
  • gas
  • muscle stiffness
  • muscle tension or tightness
  • trouble in holding or releasing urine

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, check with your doctor immediately if you notice the following side effects:

  • Confusion
  • fever
  • muscle rigidity

For Healthcare Professionals

Applies to tolcapone: oral tablet


In general, tolcapone (the active ingredient contained in Tasmar) was well tolerated in clinical trials with most adverse events being mild to moderate in severity. Dyskinesia and other dopaminergic-related effects were the most frequently reported adverse events in patients with motor fluctuations. Diarrhea was the most common nondopaminergic adverse event, occurring in up to 26% of patients who received tolcapone, and necessitating discontinuation of treatment in approximately 5% to 10% of patients.[Ref]


Hepatic side effects have included severe liver damage, including fulminant liver failure resulting in death. Three cases of fatal fulminant hepatic failure have been reported from more than 40,000 patient years of worldwide use. Increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) have also been reported.[Ref]


Gastrointestinal side effects have included nausea (30% to 35%), anorexia (19% to 23%), diarrhea (16% to 18%), vomiting (8% to 10%), constipation (6% to 8%), xerostomia (5% to 6%), abdominal pain (5% to 6%), dyspepsia (3% to 4%), flatulence (2% to 4%), and dry mouth.[Ref]


Musculoskeletal side effects have included dystonia (19% to 22%), muscle cramps (17% to 18%), stiffness (2%), arthritis (1% to 2%), and hypertonia (1%).[Ref]


Respiratory side effects have included upper respiratory tract infection (5% to 7%), dyspnea (3%), and sinus congestion (1% to 2%).[Ref]


Genitourinary side effects have included urine discoloration (2% to 7%), urinary tract infection (5%), and micturition disorder (1% to 2%).[Ref]


Cardiovascular side effects have included chest pain (1% to 3%), hypotension (2%), chest discomfort (1% to 2%), and orthostatic symptoms.[Ref]


Dermatologic side effects have included dermal bleeding (1%), alopecia (1%), and increased sweating. At least one case of vitiligo has also been reported.[Ref]

A case report of vitiligo has been reported in a 50-year-old man with Parkinson's disease one week after the start of therapy with tolcapone 300 mg per day.[Ref]


Oncologic side effects have included tumors of the skin (1%) and tumors of the uterus (1%).[Ref]


Ocular side effects have included cataracts (1%) and inflamed eyes (1%).[Ref]

Nervous system

Nervous system side effects have included dyskinesia (42% to 51%), sleep disorder (24% to 25%), excessive dreaming (16% to 21%), somnolence (14% to 18%), orthostatic complaints (17%), dizziness (6% to 13%), confusion (10% to 11%), headache (10% to 11%), hallucination (8% to 10%), syncope (4% to 5%), hyperkinesia (2% to 3%), paresthesia (1% to 3%), hypokinesia (1% to 3%), loss of balance (2% to 3%), mental deficiency (1%), agitation (1%), hyperactivity (1%), and neuroleptic malignant-like syndrome. Akathisia, insomnia and sleep disturbances have also been reported.[Ref]

The neuroleptic malignant-like syndrome was reported in an elderly patient. It was caused by abrupt withdrawal of tolcapone.[Ref]


Other side effects have included fatigue (3% to 7%), falling (4% to 6%), increased sweating (4% to 7%), influenza (3% to 4%), neck pain (2%), burning (1% to 2%), irritability (1%), malaise (1%), panic reaction (1%), euphoria (1%), and fever (1%).[Ref]


1. Olanow CW, Watkins PB "Tolcapone: An Efficacy and Safety Review (2007)." Clin Neuropharmacol 30 (2007): 287-294

2. "Product Information. Tasmar (tolcapone)." Roche Laboratories, Nutley, NJ.

3. Dingemanse J "Issues important for rational COMT inhibition." Neurology 55(11 Suppl 4) (2000): S24-7; discussion S28-32

4. Hanson MR, Galvez-Jimenez N "Catechol-O-methyltransferase inhibitors in the management of Parkinson's disease." Semin Neurol 21 (2001): 15-22

5. Sabate M, Bosch A, Pedros C, Figueras A "Vitiligo associated with tolcapone and levodopa in a patient with Parkinson's disease." Ann Pharmacother 33 (1999): 1228-9

6. Iwuagwu CU, Riley D, Bonomo RA "Neuroleptic malignant-like syndrome in an elderly patient caused by abrupt withdrawal of tolcapone, a catechol-O-methyl transferase inhibitor." Am J Med 108 (2000): 517-8

Some side effects of Tasmar may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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