Featured Research

from universities, journals, and other organizations

Ritalin May Improve Parkinson's Symptoms, OHSU Study Says

Date:
May 7, 2004
Source:
Oregon Health & Science University
Summary:
A well-known drug used to treat hyperactive children boosts the potency of another drug that reduces Parkinson's disease symptoms, an Oregon Health and Science University study has found.

PORTLAND, Ore. – A well-known drug used to treat hyperactive children boosts the potency of another drug that reduces Parkinson's disease symptoms, an Oregon Health & Science University study has found.

Related Articles


Scientists at the OHSU Parkinson Center of Oregon found that methylphenidate, known commercially as Ritalin, bolsters the effects of levodopa, a drug converted in the brain to dopamine. Methylphenidate inhibits the reabsorption of dopamine into nerve cells, increasing the neurotransmitter's potency.

Parkinson's disease is caused by a deficiency of nerve cells that produce dopamine.

A parallel study by Parkinson center researchers found that paroxetine, a popular antidepressant best known under the brand name Paxil, doesn't augment the effects of levodopa and has little benefit in reducing physical symptoms of Parkinson's disease.

Paroxetine is a selective serotonin reuptake inhibitor, or SSRI, a class of antidepressants that block the reabsorption of another neurotransmitter, serotonin, into nerve cells. Researchers studied it because laboratory evidence has suggested the serotonin transporter, the system through which serotonin is reabsorbed into nerve cells, may take up dopamine as well.

"Both studies looked at the effects of these drugs on Parkinson's disease," said John "Jay" G. Nutt, M.D., professor of neurology, and physiology and pharmacology, OHSU School of Medicine, and director of the Parkinson center. He also is director of the Parkinson's Disease Research, Education, and Clinical Center (PADRECC) at the Portland Veterans Affairs Medical Center. The studies were presented last week at the 56th annual meeting of the American Academy of Neurology in San Francisco.

Ritalin, the drug used in the methylphenidate study, "increases the effects of levodopa," Nutt said, while paroxetine didn't affect Parkinson's disease symptoms. However, paroxetine, when taken without levodopa, did increase the walking speed of Parkinson's patients.

"There was no evidence that (paroxetine) made Parkinson's disease worse, as some clinicians have suggested," Nutt said. "If that occurred, it probably wasn't by negatively impacting dopamine's effects."

In the Ritalin study, 14 Parkinson's disease patients with fluctuating responses to levodopa were examined. All received two-hour levodopa infusions at either minimum or maximum doses for four consecutive days, but some also received oral doses of Ritalin. Participants were then tested for symptoms of Parkinsonism, including tapping and walking speeds; dyskinesia or involuntary movements such as twitching, nodding and jerking; mood, anxiety and fatigue; and sitting blood pressure.

Ritalin amplified the effects of levodopa, particularly for those given minimum doses of levodopa. It increased, from 36 percent to 86 percent, the number of patients responding to levodopa, and it boosted the duration of levodopa response as measured by tapping and walking tests. But the severity of dyskinesia, a side effect of levodopa therapy, did not rise.

In addition, Ritalin decreased another levodopa side effect – hypotension, or low blood pressure – and it enhanced improvements levodopa made in mood and decreased fatigue. Adverse effects, in general, were minimal, and the drug had no effect when given alone to Parkinson's disease patients.

The study's findings do more than show that Ritalin improves patients' responses to levodopa, Nutt said. They confirm the importance of the dopamine transporter, the system through which dopamine is reabsorbed into nerve cells, and shows that the transporter may be a target for other levodopa-boosting drugs.

"It may be that by blocking the dopamine transporter with one drug or another, we can augment the effects of levodopa and get better control of Parkinson's disease," he said.

Pharmaceutical companies already are looking at other drugs that may block the transporter, Nutt added. And the OHSU Parkinson Center will continue to study Ritalin, including whether more doses promotes levodopa response throughout the day.

"The first study is proof of principle – blocking the dopamine transporter," Nutt said. "Now the question is, would Ritalin be the drug to do that? That's not clear."

The paroxetine study was conducted on 14 people with varying severity of Parkinson's disease. Each was given two-hour levodopa infusions; some also received paroxetine for two weeks while the rest were given a placebo. The subjects were then scored for tapping rate, tremor and dyskinesia, as well as walking speed.

Paroxetine, when given with levodopa, didn't affect tapping, dyskinesia or tremor, according to the findings. In fact, six people reported worse balance while on paroxetine.

Nutt's Ritalin study collaborators were Julie H. Carter, R.N., A.N.P., associate professor of neurology, OHSU School of Medicine, and associate director of the Parkinson center; and Gary J. Sexton, Ph.D., associate professor of public health and preventive medicine, OHSU School of Medicine. Paroxetine study collaborators were Kathryn A. Chung, M.D., assistant professor of neurology, OHSU School of Medicine and the Parkinson center, and PADRECC, Portland VA Medical Center.

Both studies were supported by the National Institute of Neurological Disorders and Stroke, National Institutes of Health; PADRECC; and the National Parkinson Foundation.


Story Source:

The above story is based on materials provided by Oregon Health & Science University. Note: Materials may be edited for content and length.


Cite This Page:

Oregon Health & Science University. "Ritalin May Improve Parkinson's Symptoms, OHSU Study Says." ScienceDaily. ScienceDaily, 7 May 2004. <www.sciencedaily.com/releases/2004/05/040507082157.htm>.
Oregon Health & Science University. (2004, May 7). Ritalin May Improve Parkinson's Symptoms, OHSU Study Says. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2004/05/040507082157.htm
Oregon Health & Science University. "Ritalin May Improve Parkinson's Symptoms, OHSU Study Says." ScienceDaily. www.sciencedaily.com/releases/2004/05/040507082157.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Tryptophan Isn't Making You Sleepy On Thanksgiving

Tryptophan Isn't Making You Sleepy On Thanksgiving

Newsy (Nov. 27, 2014) — Tryptophan, a chemical found naturally in turkey meat, gets blamed for sleepiness after Thanksgiving meals. But science points to other culprits. Video provided by Newsy
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) — Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins