Males and females 30 to 80 years of age, inclusive.
Diagnosis of idiopathic PD meeting the United Kingdom Parkinson's disease Society Brain Bank criteria.
Levodopa-induced dyskinesia present greater than 25% of the day as per MDS-UPDRS.
Dyskinesia of at least moderate severity as per MDS-UPDRS
Amantadine and Monoamine Oxidase (MAO) inhibitors must be discontinued at least three weeks prior to randomization.
Subjects currently receiving anti-parkinsonian medications, including all Levodopa preparations are eligible provided they have been on a stable dose of these medications for at least 1 month prior to randomization.
Concomitant use of antidepressants such as selective serotonin reuptake inhibitors are allowed, provided the dose has been stable for at least 1 month prior to randomization.
You may not be if
Subject had a prior surgery for PD except Deep Brain Stimulation (Deep Brain Stimulation must not have been performed within one year of screening)
Hoehn and Yahr score of 5 when "off".
Subject with Cognitive impairment and/or history of psychiatric manifestations or active hallucinations.
Subjects with any history of complete heart block, QTc prolongation, or torsades de pointes.
Subjects with any family history of congenital QT interval prolongation syndrome.
Subjects with history of postural syncope, or any history of unexplained syncope within the last 12 months.
Subjects with a history of substance and/or alcohol abuse within the past 2 years.
