Tolcapone
Tolcapone is an oral tablet used alongside levodopa and carbidopa to treat the signs and symptoms of Parkinson's disease.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 3 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Tolcapone carries a serious FDA boxed warning about the risk of life-threatening liver failure. Cases of fatal liver failure have been reported in people taking tolcapone, most occurring within the first 6 months of treatment. Because of this, tolcapone should only be used when other add-on Parkinson's treatments have not worked or are not suitable.
Before starting tolcapone, your doctor must check your liver. It should not be started if you already have liver disease or abnormal liver test results. Regular blood tests to monitor your liver are required throughout treatment. Watch for warning signs of liver damage: yellowing of the skin or eyes, dark urine, clay-colored stools, unusual tiredness, loss of appetite, or pain in the upper right abdomen — and report them to your doctor immediately. If you are taken off tolcapone because of liver injury, you should generally not take it again, as restarting it significantly raises the risk of further liver damage.
📖 Tolcapone: Patient Information Guide
A plain-language walkthrough of Tolcapone — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Tolcapone is an oral tablet used as an adjunct (add-on) therapy to levodopa and carbidopa for Parkinson's disease. It is not a standalone treatment — it must be used alongside levodopa/carbidopa.
- Tasmar (tolcapone) tablets: Indicated as an add-on to levodopa/carbidopa for the signs and symptoms of idiopathic Parkinson's disease — ordinarily in patients experiencing symptom fluctuations who have not responded satisfactorily to or are not appropriate candidates for other adjunctive therapies.
- Tolcapone tablets (generic): Same indication — adjunct to levodopa/carbidopa for idiopathic Parkinson's disease, prioritized for patients with symptom fluctuations not well controlled by other add-on treatments.
- Effectiveness has been shown in clinical trials both in patients who experience end-of-dose wearing-off (symptoms returning before the next levodopa dose) and in those with more stable responses to levodopa.
- If tolcapone does not produce a clear, noticeable benefit within 3 weeks of starting, it should be discontinued.
⚙️How it works▾
Tolcapone blocks an enzyme called COMT (catechol-O-methyltransferase), which normally breaks down levodopa in the blood and brain before it can be fully used. When COMT is blocked, levodopa stays in the bloodstream longer and at more consistent levels. This leads to steadier dopamine stimulation in the brain, which helps reduce the fluctuating motor symptoms of Parkinson's disease. Because tolcapone raises levodopa levels, your prescriber may need to lower your levodopa dose to avoid increased side effects.
💊How it's taken▾
Tolcapone tablets are taken by mouth three times a day. The first dose of the day is taken at the same time as your first levodopa/carbidopa dose, with the second and third doses spaced approximately 6 and 12 hours later. The tablets may be taken with or without food, though eating close to a dose (within 1 hour before or 2 hours after) can slightly reduce absorption by 10–20%.
- Can be used with both immediate-release and sustained-release formulations of levodopa/carbidopa.
- Your levodopa dose may need to be reduced after starting tolcapone — your prescriber will guide this adjustment.
- Do not adjust your dose on your own; always follow your prescriber's instructions.
🤒Side effects — in detail▾
The most common side effects seen in clinical trials include:
- Dyskinesia (uncontrolled, involuntary movements) — the most frequently reported
- Nausea and vomiting
- Diarrhea — the most common reason people stopped taking the medication
- Sleep disturbances and excessive dreaming
- Somnolence (unusual drowsiness or sleepiness)
- Loss of appetite
- Hallucinations
- Urine discoloration (harmless bright yellow to orange color)
- Dizziness and orthostatic complaints (lightheadedness when standing up)
Serious reactions to watch for include signs of liver damage (jaundice, dark urine, right-sided abdominal pain, extreme fatigue) and sudden uncontrolled sleep episodes during daily activities — both require contacting your doctor right away.
⚠️Warnings & precautions▾
- Liver failure risk: Fatal liver failure has been reported with tolcapone. Liver enzyme blood tests are required before starting and regularly during the first 6 months, then periodically after. Stop the medication and contact your doctor immediately if you notice jaundice, dark urine, clay-colored stools, loss of appetite, or unusual fatigue.
- Do not restart after liver injury: If you were taken off tolcapone because it harmed your liver, you should generally not take it again — restarting greatly increases the risk of further serious liver damage.
- Sudden sleep episodes: Tolcapone can cause sudden, unexpected sleep during everyday activities (including driving), sometimes without warning drowsiness. Do not drive or operate machinery until you know how this medication affects you.
- Non-selective MAO inhibitors: Do not use tolcapone with non-selective MAO inhibitors (like phenelzine or tranylcypromine) — the combination can dangerously impair catecholamine breakdown.
- Muscle breakdown risk: Patients with severe involuntary movements (dyskinesia) or muscle spasms (dystonia) should be treated with caution because of the risk of rhabdomyolysis (dangerous muscle breakdown).
🔀What it interacts with▾
Tolcapone can interact with several drugs — always give your pharmacist and doctor a full medication list before starting.
- Non-selective MAO inhibitors (e.g., phenelzine, tranylcypromine): Should not be taken together with tolcapone — this combination blocks the major pathways that break down catecholamines in the body.
- Warfarin (blood thinner): Tolcapone may affect warfarin's effectiveness; clotting levels (INR) should be monitored more closely when used together.
- Desipramine (tricyclic antidepressant): Taking desipramine with tolcapone and levodopa/carbidopa can increase overall side effects — use with caution.
- COMT-substrate drugs (alpha-methyldopa, dobutamine, apomorphine, isoproterenol): Tolcapone may change how these drugs behave in the body; dose adjustments may be needed.
- Selegiline (selective MAO-B inhibitor): Can be taken with tolcapone; clinical trials showed a similar side effect profile with or without selegiline.
- Sedating medications: Any drug that causes drowsiness may increase the risk of sudden sleep episodes when combined with tolcapone.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Liver disease: Tolcapone must not be started if you have liver disease or significantly abnormal liver enzyme levels.
- Previous tolcapone liver injury: If you were stopped from tolcapone due to drug-related liver damage, you should not take it again.
- Allergy: Do not take tolcapone if you have had a hypersensitivity (allergic) reaction to it or any of its ingredients.
- History of rhabdomyolysis or medication-related hyperpyrexia/confusion: Tolcapone is contraindicated if you have a history of non-traumatic muscle breakdown or episodes of high fever and confusion possibly caused by a medication.
- Severe dyskinesia or dystonia: Tell your doctor — these conditions require extra caution due to the risk of muscle breakdown.
- Sleep disorders: Discuss with your prescriber, as existing sleep problems increase the risk of dangerous drowsiness or sudden sleep episodes.
- Renal (kidney) impairment: No dose adjustment is recommended for mild to moderate kidney impairment, but discuss your full health history with your prescriber.
- Women: Female patients appear more likely to experience elevated liver enzymes and somnolence — monitoring is especially important.
🚑If you take too much▾
Taking much more tolcapone than prescribed can cause nausea, vomiting, and dizziness, especially when combined with levodopa/carbidopa. If an overdose is suspected, hospitalization is advised and general supportive care is recommended. Hemodialysis (a kidney-filtering procedure) is unlikely to help remove tolcapone from the body due to how it is processed.
📡Pharmacodynamics — effects in the body▾
Tolcapone reversibly blocks the COMT enzyme in the body. After a single dose, it can inhibit more than 80% of COMT activity in red blood cells. With regular three-times-daily dosing, COMT activity remains suppressed by 30–45% even at its lowest blood levels between doses. This sustained enzyme inhibition is what keeps levodopa available in the bloodstream at more consistent levels throughout the day.
🔬Pharmacokinetics — how your body processes it▾
Tolcapone is absorbed quickly after an oral dose, reaching peak blood levels in about 2 hours, with roughly 65% of the dose making it into the bloodstream. It is almost entirely bound to proteins in the blood (over 99.9%), mainly albumin, and does not distribute widely into tissues. The drug is broken down almost completely by the liver — primarily through a process called glucuronidation — and has a short half-life of 2 to 3 hours, meaning it does not build up significantly in the body. About 60% is eliminated in the urine and 40% in feces.
📦How to store it▾
Store in tight containers at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) .
📄 Written from Tolcapone’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Tolcapone
58 supplements and herbal products have documented interactions with Tolcapone in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 4
- Moderate · 45
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Tolcapone — the kind of thing our pharmacy team would talk through with you at the counter.
Why do I need blood tests while taking tolcapone? Can't I just take it and see how I feel? ▾
My urine looks orange or yellow since I started tolcapone. Should I be worried? ▾
I've heard tolcapone can make you fall asleep suddenly. Is that really true? ▾
What side effects are most likely when I first start tolcapone? ▾
Are there any medications I absolutely cannot take with tolcapone? ▾
What should I do if I don't feel any better after a few weeks on tolcapone? ▾
Is Tolcapone available over the counter? ▾
When was Tolcapone first available? ▾
Who makes Tolcapone? ▾
💬 Answers drafted from Tolcapone’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Tolcapone comes
Tolcapone is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Tablet
How this form is used
- Tasmar (tolcapone) tablets are used as an add-on to levodopa/carbidopa for the signs and symptoms of idiopathic Parkinson's disease in patients experiencing symptom fluctuations who have not responded adequately to other add-on therapies.
- Tolcapone tablets are used as an add-on to levodopa/carbidopa for the signs and symptoms of idiopathic Parkinson's disease in patients experiencing symptom fluctuations who have not responded adequately to other add-on therapies.
- Tasmar tablets are taken three times daily — the first dose together with the first daily dose of levodopa/carbidopa, then approximately 6 and 12 hours later.
- Tolcapone tablets are taken three times daily — the first dose together with the first daily dose of levodopa/carbidopa, then approximately 6 and 12 hours later.
- Both Tasmar and tolcapone tablets may be taken with or without food, though eating within 1 hour before or 2 hours after a dose can slightly reduce absorption.
- Tasmar and tolcapone tablets can be combined with both immediate-release and extended-release formulations of levodopa/carbidopa.
📊 Tolcapone across the U.S. market
How Tolcapone appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (3) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
🔍 Compare Tolcapone products
A representative set of FDA-listed product records for Tolcapone — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 100 mg | Oral | Bausch Health US LLC | NDA | View NDC → |
| 100 mg | Oral | Ingenus Pharmaceuticals, LLC | ANDA | View NDC → |
| 100 mg | Oral | Oceanside Pharmaceuticals | NDA AUTHORIZED GENERIC | View NDC → |
| 💊Bulk drug substance | ||||
| 1 g/g | — | Anthem Biosciences Limited | BULK INGREDIENT FOR HUMAN PRESCRIPTION COMPOUNDING | View NDC → |
| 1 kg/kg | — | Cohance Lifesciences Limited | BULK INGREDIENT FOR HUMAN PRESCRIPTION COMPOUNDING | View NDC → |
| 25 kg/25 kg | — | Piramal Pharma Limited | BULK INGREDIENT | View NDC → |
Showing 6 of 6 products — FDA National Drug Code Directory. See every product, package size and price: browse all 6 Tolcapone NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Tolcapone — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Tolcapone in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Tolcapone went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 72937 1 dose form · 2 strengths
-
Dose form (SCDF) Oral Tablet RxCUI 374153In current FDA listings
Look up RxCUI 72937 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Tolcapone is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Tolcapone belongs to the Catechol-O-Methyltransferase Inhibitor class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 3 FDA-filed SPL label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Oceanside Pharmaceuticals is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.