Parkinson's Alternative: Neurologists' Study Shows Ropinirole Drug Offers Longer Relief from Symptoms Than Seen in L-dopa
- Apr 03 2007
Patients with Parkinson's disease have long battled the roller-coaster-like effects of the current medicines: Over the course of the disease, the gold standard treatment, L-dopa, doesn't control the tremors, stiffness, slowness and walking problems, and many don't know when during the day it will stop working.
What's more, L-dopa's side effects - uncontrolled dancelike movements - can be as debilitating as the disease itself.
In the race to find more effective treatments, the latest study, published in the journal Neurology, shows that a once-a-day prolonged-release formula of the federally approved drug ropinirole gives patients two extra hours of symptom relief without worsening the disturbing dyskinesias, or jerky movements, that are seen with L-dopa therapy.
"The fewer pills, the less complicated it will be for Parkinson's patients," said Dr. Rajesh Pahwa of the University of Kansas Medical Center, the lead investigator for the study.
In the study, 393 patients who were having problems managing their symptoms with L-dopa alone were given the experimental formulation of ropinirole once a day.
According to the published findings, more than half the patients on the formulation experienced marked improvement, compared with 14 percent of those who took a placebo.
Parkinson's disease begins when dopamine-containing cells in an area of the brain called the substantia nigra become damaged and die.
Symptoms begin when about 90 percent of the dopamine in this region is depleted. This brain chemical controls movement, coordination and mood.
With fewer dopamine neurons in the region, communication between the brain and the body is slowed.
L-dopa is used to replace the diminishing dopamine chemical. For a while, patients have good control of their symptoms. But as the disease progresses, each dose works for only three to four hours.
The effect of the drug becomes unpredictable, and 16 percent of people on it develop the dancelike movements within nine months of therapy.
In Parkinson's, there is less dopamine at the juncture, or synapse, between cells. Dopamine agonists like ropinirole work to replace dopamine.
Last week, the Parkinson's drug Pergolide was voluntarily withdrawn from the market after several years of reports that patients were developing heart valve damage.
This medicine is an older preparation called an ergot dopamine agonist. No such side effects have been identified with ropinirole or any of the newer non-ergot agonists.
Dr. Warren Olanow, professor and chairman of neurology at Mount Sinai School of Medicine in Manhattan, said Parkinson's doctors are now using these dopamine agonists as the first therapy early on in the disease so that they can push back the need for L-dopa.
There is more treatment hope for Parkinson's patients. A patch of experimental medicine is now making its way through the Food and Drug Administration regulatory approval process. Also, gene therapy trials are now being carried out in patients, Olanow said.
A million Americans have Parkinson's, and as the population ages, the number of new patients is expected to rise.
Source Date: Apr 03 2008
Source Publication: Newsday
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