EMBARGOED FOR RELEASE UNTIL WEDNESDAY, MAY 20, 1998 For more information contact: Julie Gilbert (612) 695-2763 or [email protected]
Drug Improves Involuntary Muscle Movements & Motor Fluctuations in ParkinsonÃs Patients
ST. PAUL, MN (May 20, 1998) ñ The generic drug amantadine can improve motor fluctuations and dyskinesias (jerky or fragmented involuntary muscle movements) that occur after long-term use of ParkinsonÃs medications, according to a study published in the May issue of Neurology, the scientific journal of the American Academy of Neurology.
"By adding amantadine to ParkinsonÃs treatment therapy many patients in the advanced stages of ParkinsonÃs disease can expect a better quality of life and improved muscular functioning," said Thomas N. Chase, MD, of the National Institute of Neurological Disorders & Stroke in Bethesda, MD. "Amantadine is cheap, available, safe and makes a substantial difference for patients."
Levodopa is the most common drug used to treat ParkinsonÃs disease; however, after long-term use many patients develop complications such as dyskinesias and motor fluctuations. Symptoms can swing dramatically from very severe to mild and back again within a short time period. "Eventually, these levodopa-associated complications contribute significantly to patient disability," said Chase.
Chase performed a double-blind, placebo-controlled study on 14 patients with advanced ParkinsonÃs disease. The study determined the effects of amantadine on levodopa-associated dyskinesias and motor fluctuations.
Amantadine, in combination with levodopa therapy, reduced the severity of dyskinesias and motor fluctuations by 50 percent. In all cases, the beneficial effects of levodopa were not altered.
All patients who completed the study elected to continue using amantadine as part of their drug therapy.
"This discovery is exciting because surgery was the only option to treat dyskinesias and motor fluctuations," he said. "Surgery is a difficult choice because it is invasive and is not an effective treatment for all patients."
Amantadine was used for decades in early-stage ParkinsonÃs disease. It was overlooked for advanced ParkinsonÃs because of its weak effects when used alone, according to Chase. The drug has also been used to treat influenza A virus infections and drug addiction.
After animal studies, researchers found that levodopa makes certain neurotransmitter receptors, called N-methyl-D-aspartate (NMDA), in the brain hypersensitive. Further studies revealed that blocking NMDA reduces some of the levodopa-associated movement difficulties. Amantadine was used in the study because it recently was found to contain NMDA-blocking properties.
Research was supported in part by the National Parkinson Foundation in Miami, FL, and the Parkinson Patients Foundation of the Netherlands.
The American Academy of Neurology, an association of more than 15,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research.
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