New Drug Treatments for Dyskinesia

We need to find a drug or combination of drugs that can effective eliminate motor symptoms of Parkinson's disease without causing dyskinesia. Scientists are working several types of drugs that appear to be promising. Adenosine A2A antagonists (e.g., istradefylline) reduce overactivity in dopamine neurons that are thought to contribute to dyskinesia. In a recent study istradefylline reduced "off" time by 3/ of an hour per day compared with placebo, but did not reduce dyskinesias. AMPA antagonists (e.g. Talampanel, Perampanel ) reduce dyskineasia indirectly by blocking chemicals that excit dopamine neurons. Talampanel has been shown to reduce levodopa-induced dyskinesias in a monkey model of PD. Perampanel and Talampanel are currently being evaluated in clinical trials. The alpha-2 adrenergic receptor antagonist fipamezole has been reported to reduce levodopa-induced dyskinesias in animals and is currently in phase 2 studies. The dopamine agonist SLV308 (Pardoprunox) has been reported to reduce dyskineasia in animals and is currently in phase 3 trials.