Anticholinergics block acetylcholine - a chemical messenger found in your brain and body. They are not used very often to treat Parkinson's.

How do anticholinergics work?

These drugs block the action of acetylcholine, which helps to send messages in the brain and from your nerves to your muscles.

When are anticholinergics used?

These drugs are old and are now not used very often for Parkinson’s. Sometimes they are prescribed for reducing tremor and muscle stiffness.

They can be used on their own, especially in the early stages of Parkinson’s, before levodopa is prescribed.

Anticholinergics can also be used with levodopa or a glutamate antagonist.

They are taken as tablets or as a liquid.

What types of anticholinergics are there?


  • Unbranded (liquid)


  • Kemadrin (tablets)
  • Unbranded (tablets, syrup)
  • Unbranded (solution for injection)

Trihexyphenidyl (benzhexol)

  • Unbranded (tablets, syrup)

Benefits of anticholinergics

Possible effect on mild movement symptoms

Older medical studies have found some benefits from taking anticholinergics for Parkinson’s symptoms. They can be effective for younger people in the early stages of Parkinson’s.

Possible effect on other Parkinson’s symptoms

Anticholinergics may also be used to reduce saliva production, if you have a problem with drooling.

Oxybutynin is an anticholinergic that is used in people without Parkinson’s to reduce bladder contractions that can cause a strong, frequent urge to urinate. It is only used very cautiously in people with Parkinson’s as it may reduce how much levodopa your body can be absorb.

Risks and side effects of anticholinergics

Limited effect on movement symptoms

These drugs are not recommended in guidelines for the NHS in Scotland. The authors of these guidelines say the advantages do not outweigh the disadvantages.

Memory problems

Anticholinergics are not very often given to people with Parkinson’s because they can cause memory problems or make them worse.

This can happen at any age, but particularly for older people. If you’re taking anticholinergics, your specialist or Parkinson’s nurse must closely monitor your situation.

other side effects

The patient information leaflet that comes with your medication will tell you the full range of side effects that you may experience.

Some of the possible side effects include:

  • dry mouth
  • blurred vision
  • constipation
  • dizziness
  • trouble urinating
  • confusion
  • hallucinations
  • forgetfulness

Find out more about the side effects of Parkinson's drugs.

Last updated August 2015. We review all our information within 3 years. If you'd like to find out more about how we put our information together, including references and the sources of evidence we use, please contact us at [email protected].