Back to top

Glutamate antagonist

There is one glutamate antagonist, amantadine, that can be prescribed to treat Parkinson's symptoms. It can be called either amantadine or Symmetrel.

How does a glutamate antagonist work?

It’s not known exactly how this drug works for Parkinson’s. It may affect how the brain reacts to certain chemicals.

When is a glutamate antagonist used?

Amantadine can be used to treat tremor and rigidity.

It isn’t used very often and is unlikely to be prescribed alone. It's usually given with other drug treatments and can be used at all stages of Parkinson’s.

It is started at a lower dose and the amount is stepped up gradually.

What types of glutamate antagonists are there?

  • Amantadine (capsules, syrup)

Benefits of glutamate antagonists

Fewer movement side effects

The SIGN guidelines for the NHS in Scotland and the NICE guidelines for the NHS in England and Wales (which are also recommended for use in Northern Ireland) say there is not enough scientific evidence to support this drug as a first choice in early Parkinson’s.

But for some people, amantadine may reduce dyskinesia (involuntary movements) caused by your other Parkinson’s drugs, without making your Parkinson’s symptoms worse.

Risks and side effects of glutamate antagonists

Limited effect on Parkinson’s

Amantadine is not a first choice for the treatment of Parkinson’s and it may have only a mild effect. Over time, amantadine can become less effective.

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:

  • feeling nervous, anxious or overexcited
  • blurred vision, fainting, confusion or dizziness - If you have these side effects, it is not safe to drive or use machinery.
  • poor concentration
  • headaches
  • hallucinations
  • movement problems
  • sleep problems
  • fast or irregular heartbeat
  • loss of appetite
  • nausea and vomiting
  • constipation
  • sweating
  • swollen hands and ankles
  • skin reactions

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