Study On Side Effects of Parkinson’s Medication

A new genetic study may help those looking for ways to avert some of the troubling side effects of a common medication used to treat Parkinson’s disease.

Parkinson’s is sometimes treated with medication that increases dopamine activity in the brain. In some patients that triggers impulsivity, such as compulsive gambling, shopping, eating, or hyper-sexuality.


Impulse Control Disorder

But in a study published in the journal Annals of Clinical and Translational Neurology, researchers have identified genetic variants in Parkinson’s patients at risk for that problem. Using genetic modeling could help identify patients who are more likely to develop impulse control disorder due to prescribed dopaminergic medications. 

Using machine learning and statistical techniques, the team was able to create a risk model to identify those at the highest risk. 

In the paper, the researchers suggest that this might ultimately be used to make it easier for physicians treating those with Parkinson’s disease to identify those that should be prescribed an alternative to medication that increases dopamine activity, like levodopa.

Risk Models for Drug Interactions

The study used data from about 5,700 individuals with Parkinson’s disease. Most of the data came from 23andMe Parkinson’s research participants who consented to participate, with the remainder coming from two other research cohorts, one at the University of Pennsylvania and the other at the Parkinson’s Progression Markers Initiative. 

The research involved two major steps. The first looked at genetic variants associated with impulse control disorder in people with Parkinson’s. Once they identified these variants, researchers used machine learning and statistical techniques to create a risk model. This helped them identify individuals who were more likely to develop impulse control disorder if the prescribed medication that affected the dopamine activity in their brain.

In evaluating the model, the researchers said it performed better than similar pharmacogenetic models already used in prescribing anti-platelet drugs.

While dopaminergic drugs are very important and effective in treating motor control issues in Parkinson’s patients, impulse control disorder side effects are relatively common. In this study, n 20-30 percent of those treated with dopaminergic drugs experienced impulse control disorder.  

Applying this pharmacogenetic approach could be effective at identifying those individuals better served by the use of an alternative to dopaminergic medications. One of those alternatives include the drug levodopa, the researchers said.