Why do Parkinson’s drugs cause dyskinesia?

Dyskinesia is a debilitating side effect of Parkinson’s medications that can significantly impact on quality of life. In this post, we find out why medications, like levodopa, cause this side effect and how serotonin signalling is involved.

Dr Beckie Port
Nov 6, 2017 · 6 min read
Image for post
Image for post

“It makes eating very difficult. And walking is almost impossible.”

They are intrinsically linked to the medications used to help manage the condition — a side effect, not a symptom — and are mostly associated with levodopa based medications, however dopamine agonists can also cause dyskinesia. While they can be present early in the condition, they often become more problematic in the later stages of Parkinson’s when people have been taking Parkinson’s medications for several years.

“Even though I take Amantadine to control the dyskinesia, I still have involuntary movement like right now (my left leg) and it is exhausting. It is also embarrassing in public when I can’t control it.”

Image for post
Image for post

Overloading the system

In Parkinson’s, the dopamine producing cells are slowly lost over time. Normally these cells use an amino acid called tyrosine to make levodopa inside the cells, which is then turned into dopamine. The dopamine is then packaged up and released from the cell allowing the brain cells to communicate messages about movement.

“It can be a little embarrassing, especially if I am on a train, and I sometimes feel a bit self-conscious. I also feel that my body is going out of control.”

As well as the peaks that occur soon after levodopa medications are taken, as the drug is used and cleared from the body people can experience wearing off of their medication. When this happens there is not enough dopamine in the synapse and movement becomes slowed again.

“I have to plan to do things when my medication is working at its best and the involuntary movements are fewer & less disruptive.”

Like levodopa based medications, dopamine agonists can cause dyskinesia by overloading the system. But dopamine agonists tend to be longer acting, which helps to maintain stable levels of the drug in the brain, so dyskinesia are rarer with this drug. Researchers have developed longer acting, slow release levodopa tablets, which can help to maintain symptom control and manage this side effect, however this is just one way levodopa drugs can cause dyskinesia.

Hijacking serotonin signalling

There are a number of neurotransmitters that the brain uses to communicate, dopamine is just one. And inside the brain different cells that are responsible for using these different molecules are all mixed together.

Image for post
Image for post

Targeting serotonin cells to control dopamine release

Better understanding of the different ways levodopa medications are causing dyskinesia is allowing researchers to develop new drugs to control this side effect.

More about Parkinson’s medications

You can find more information about Parkinson’s treatments and therapies on the Parkinson’s UK website. If you have any concerns about your medication not working, please speak your medical team.


Parkinson’s UK

Get the latest research news, discover more about…

Dr Beckie Port

Written by

Research Communications Manager at @ParkinsonsUK. Ex-researcher in oncology and virology.

Parkinson’s UK

Get the latest research news, discover more about Parkinson’s and read about how others are getting involved. For information and support, visit www.parkinsons.org.uk

Dr Beckie Port

Written by

Research Communications Manager at @ParkinsonsUK. Ex-researcher in oncology and virology.

Parkinson’s UK

Get the latest research news, discover more about Parkinson’s and read about how others are getting involved. For information and support, visit www.parkinsons.org.uk

Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight.

Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox.

Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store