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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


The more commonly reported adverse events have included dyskinesia, nausea, sleep disorder, orthostatic complaints, and diarrhea.[Ref]


Cases of severe hepatocellular injury, including fulminant liver failure resulting in death, have been reported. As of 5-2005, 3 cases of fulminant hepatic failure had been reported from more than 40,000 patient years of worldwide use. This incidence may be 10 to 100-fold higher than the incidence in the general population. All 3 cases were reported within the first 6 months of treatment initiation. Analysis of laboratory monitoring indicates that when present, transaminase elevations generally occur within the first 6 months. It is not clear whether periodic monitoring will prevent the occurrence of fulminant liver failure, but it is believed that early detection and immediate withdrawal enhances the likelihood for recovery.

During clinical trials, transaminase elevations to greater than 3 times the upper limit of normal (3 x ULN) occurred in 1% and 3% of patients receiving 100 mg or 200 mg three times a day, respectively. Females were more likely than males to have elevated liver enzymes (5% vs 2%). Approximately 33% of patients with elevated liver enzymes had diarrhea. Liver enzyme elevations to greater than 8 x ULN occurred in 0.3% and 0.7% of patients receiving 100 mg or 200 mg three times a day, respectively.[Ref]

Common (1% to 10%): ALT increases

Uncommon (0.1% to 1%): Hepatocellular injury[Ref]


In clinical trials, diarrhea developed in approximately 16%, and 18%, of patients receiving 100 mg or 200 mg three times a day, respectively. Diarrhea was generally regarded as mild to moderate, however, severe diarrhea occurred in 3% to 4% of patients and hospitalization was needed in 0.7% and 1.7% of patients receiving 100 mg or 200 mg, respectively. Diarrhea was the most common adverse reaction resulting in discontinuation. No consistent mechanism for tolcapone-induced diarrhea is known.[Ref]

Very common (10% or more): Nausea (up to 35%), diarrhea (up to 18%), vomiting (up to 10%)

Common (1% to 10%): Constipation, xerostomia, abdominal pain, dyspepsia, flatulence, tooth disorder

Uncommon (0.1% to 1%): Dysphagia, gastrointestinal hemorrhage, gastroenteritis, mouth ulceration, increased salivation, abnormal stools, esophagitis, cholelithiasis, colitis, tongue disorder

Rare (0.01% to 0.1%): Cholecystitis, duodenal ulcer, gastrointestinal carcinoma, stomach atony[Ref]


Very common (10% or more): Muscle cramps (up to 18%)

Common (1% to 10%): Neck pain, flank pain, myalgia

Uncommon (0.1% to 1%): Tenosynovitis, arthrosis, joint disorder[Ref]


Very common (10% or more): Orthostatic complaints (up to 17%)

Common (1% to 10%): Syncope, palpitation

Uncommon (0.1% to 1%): Hypertension, vasodilation, angina pectoris, heart failure, atrial fibrillation, tachycardia, migraine, aortic stenosis, arrhythmia, arteriospasm, bradycardia, coronary artery disorder, heart arrest, myocardial infarct, myocardial ischemia, edema

Rare (less than 0.1%): Arteriosclerosis, cardiovascular disorder, pericardial effusion, thrombosis[Ref]

This drug enhances levodopa bioavailability and therefore can increase the occurrence of orthostatic hypotension. During clinical trials, orthostatic hypotension occurred at least once in 14% and 13% of patients receiving 100 mg or 200 mg three times a day, respectively. At least one episode of syncope was reported in 4% and 3% of patients, respectively. Approximately 0.7% of patients discontinued therapy due to events related to hypotension.[Ref]


Hallucinations occurred in 8% to 10% of patients receiving this drug in clinical trials compared to 5% in placebo. Hallucinations generally present shortly after therapy initiation and appeared to be responsive to levodopa dose reduction. Postmarketing reports of new or worsening mental status and behavioral changes have included paranoid ideation, delusions, hallucinations, confusion, psychotic-like behavior, disorientation, aggressive behavior, agitation, and delirium.

Very common (10% or more): Sleep disorder (up to 25%), excessive dreaming (up to 21%), confusion (up to 11%), hallucinations (up to 10%)

Common (1% to 10%): Agitation, irritability, mental deficiency, hyperactivity, panic reaction, euphoria, depression, emotional lability

Uncommon (0.1% to 1%): Amnesia, hostility, increased libido, manic reaction, nervousness, paranoid reaction, elusions, libido decreased, apathy, psychosis, abnormal thinking

Rare (less than 0.1%): Antisocial reaction, impulse control disorders

Postmarketing reports: New or worsening mental status and behavioral changes

Nervous system

Female patients may be more likely to develop somnolence than males. Dyskinesia may occur or be exacerbated as this drug potentiates the dopaminergic side effects of levodopa.

Very common (10% or more): Dyskinesia (up to 51%), dystonia (up to 22%), somnolence (up to 18%), dizziness (up to 13%), headache (up to 11%),

Common (1% to 10%): Hyperkinesia, hypertonia, hypesthesia, tremor, speech disorder,

Uncommon (0.1% to 1%): Neuralgia, extrapyramidal syndrome, cerebral ischemia, cerebrovascular accident, neuropathy, choreoathetosis, myoclonus, twitching, cerebral hemorrhage

Rare (less than 0.1%): Encephalopathy, hemiplegia, meningitis, delirium, neuroleptic malignant syndrome symptom complex


Common (1% to 10%): Upper respiratory tract infection, dyspnea, sinus congestion, bronchitis, pharyngitis

Uncommon (0.1% to 1%): Pulmonary embolus, increased cough, rhinitis, asthma, epistaxis, hyperventilation, laryngitis, hiccup

Rare (less than 0.1%): Apnea, hypoxia, lung edema[Ref]


This drug and its metabolites are yellow and can cause a harmless intensification in the color of the urine.[Ref]

Common (1% to 10%): Urinary tract infection, urine discoloration, micturition, urinary incontinence, impotence

Uncommon (0.1% to 1%): Rectal disorder, prostatic disorder, dysuria, nocturia, polyuria, urinary retention, urinary tract disorder, hematuria, kidney calculus, oliguria, uterine atony, uterine disorder, vaginitis

Rare (less than 0.1%): Bladder calculus, uterine hemorrhage[Ref]


Common (1% to 10%): Increased sweating, alopecia, rash

Uncommon (0.1% to 1%): Cellulitis, face edema, herpes zoster, pruritus, seborrhea skin discoloration, eczema, erythema multiforme, skin disorder, furunculosis, herpes simplex, urticaria[Ref]


Common (1% to 10%): Skin tumor, uterine tumor

Uncommon (0.1% to 1%): Carcinoma, neoplasm, prostatic carcinoma, breast neoplasm

Rare (less than 0.1%): Ovarian carcinoma[Ref]


Common (1% to 10%): Cataract, inflamed eye

Uncommon (0.1% to 1%): Diplopia, eye hemorrhage, eye pain, lacrimation disorder,

Rare (less than 0.1%): Glaucoma[Ref]


Common (1% to 10%): Fatigue, falling, loss of balance, malaise, fever, vertigo, accidental injury, tinnitus , ear pain, otitis media, parosmia

Uncommon (0.1% to 1%): Hernia, chills

Rare (0.01% to 0.1%): Death[Ref]


Uncommon (0.1% to 1%): Allergic reaction


Common (1% to 10%): Influenza

Uncommon (0.1% to 1%): Fungal infection, viral infection, bacterial infection, abscess


1. "Product Information. Tasmar (tolcapone)." Valeant Pharmaceuticals, Costa Mesa, CA.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.