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Key points about tolcapone

  • Tolcapone is used to treat the symptoms of Parkinson's disease.
  • Tolcapone is commonly called Tasmar.
  • Find out how to take it safely and the possible side effects.
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Tolcapone is used together with levodopa + carbidopa or levodopa + benserazide to treat the symptoms of Parkinson's disease, or Parkinson-like symptoms such as tremor, shakiness, stiffness, and difficulty moving.

Many people taking levodopa for Parkinson's disease have problems with the effects of the levodopa wearing off between doses. This causes the Parkinson's symptoms to return or get worse. Tolcapone blocks a certain natural substance (COMT enzyme) that breaks down the levodopa in the body. This allows the levodopa to last longer so that it doesn't wear off before the next dose.

  • In Aotearoa New Zealand, tolcapone is available as tablets (100 mg).
  • The usual dose of tolcapone is 1 tablet (100 mg) 3 times a day. Some people may need 2 tablets 3 times a day.
  • You will be started on a low dose, and then your doctor might increase your dose to control your symptoms.
  • Always take your tolcapone exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much tolcapone to take, how often to take it, and any special instructions.

  • Timing: Take your tolcapone at the same times each day. You can take tolcapone with or without food. Take your first tolcapone dose of the day at the same time as your levodopa + carbidopa dose or levodopa + benserazide dose.
  • Swallow the tablets whole, with water. Do not break or crush the tablets, and do not take any tablets that are damaged, because they have a bitter taste.
  • Limit or avoid alcohol while taking tolcapone. It increases your chance of having side effects.
  • Missed dose: If you do miss a dose and it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time or very close together.
  • Keep taking tolcapone regularly. Do not stop taking tolcapone without talking to your doctor first. Stopping treatment suddenly can cause serious problems.
  • Interactions: Tolcapone can interact with some medications, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting tolcapone or any other new products.

Like all medicines, tolcapone can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Liver problems
In rare cases, tolcapone can cause liver damage which can be dangerous. Your doctor will do regular blood tests to check how well your liver is. Look out for signs of liver damage which includes symptoms such as anorexia, nausea, vomiting, tiredness, tummy pain, dark urine, or pruritus (itchy skin). Tell your doctor immediately or ring Healthline 0800 611 116 if you have any of these.

Side effects What should I do?
  • Changes in the colour of your urine – it can cause your urine to look more yellow or orange
  • This is not harmful unless it is quite dark.
    Dark urine may be a sign of problems with your liver (see below). 
  • Feeling or being sick (nausea)
  • This is common when you first start taking tolcapone.
  • Try taking your dose with food.
  • Falling asleep suddenly during daily activities (eg, talking on the phone, or driving)
  • This sleep effect can occur without any feelings of drowsiness beforehand, and can happen anytime during treatment with this medication
  • Tell your doctor.
  • Do not drive or use tools until you know how this medicine affects you and until these have stopped happening.
  • Avoid drinking alcohol.
  • Feeling dizzy or faint when you stand up (due to a sudden drop in blood pressure)
  • Be careful when getting up from either lying down or sitting, to avoid falls.
  • Tell your doctor.
  • Signs of problems with your liver such as yellowing of the skin or eyes, dark urine, itchy skin, pain in the abdomen
  • Tell your doctor immediately or ring Healthline 0800 611 116
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

The following links have more information on tolcapone. 

Tolcapone Patient Information(external link) NZ Formulary
Tasmar(external link) Medsafe Consumer Information Sheet, NZ
Medication used in the treatment of Parkinson's(external link) Parkinson's New Zealand
Parkinson's and complementary therapies(external link) Parkinson's New Zealand


5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ, 2019 English(external link), te reo Māori(external link)


  1. Tolcapone(external link) NZ Formulary
  2. Tasmar®(external link) Medsafe, NZ
  3. The management of Parkinson’s disease – which treatments to start and when?(external link) BPAC, NZ, 2014

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Maya Patel, Pharmacist, Auckland

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