Terazosin and Parkinson's Disease Extension Study

The Effect of alpha1- Adrenergic Receptor Antagonist Therapy on Cardiac and Striatal Transporter Uptake in Pre-Motor and Symptomatic Parkinson's Disease: A Follow up Study

The purpose of this study is to investigate the long-term effects of treatment with the selective post-synaptic a1-adrenergic blocker terazosin on serial in a population of subjects with defined pre-motor Parkinson's disease (PD) risks and abnormal imaging exams. Imaging changes will be correlated to the presence and severity of motor and non-motor symptoms of PD, measured by validated clinical scales and cardiac autonomic function tests.

The purpose of this study is to investigate the long-term effects of treatment with the selective post-synaptic a1-adrenergic blocker terazosin on serial 123 Ioflupane Dopamine Transporter single-photon emission-computed tomography (123I-FP DAT-SPECT) in a population of subjects with defined pre-motor PD risks (i.e., RBD and at least one among hyposmia, constipation, depression and color vision abnormality) and abnormal Iodine-123 meta-iodobenzylguanidine (123I-MIBG) uptake. Imaging changes will be correlated to the presence and severity of motor and non-motor symptoms of PD, measured by validated clinical scales and cardiac autonomic function tests. The rate of RBD clinical conversion to PD will be estimated and compared to available data in the literature.

Inclusion Criteria:

• Enrolled in the study "The Effect of alpha1- adrenergic receptor antagonist Therapy on Cardiac and Striatal Transporter Uptake in Pre-Motor and Symptomatic Parkinson's Disease" (STUDY #000540)
• Capacity to give informed consent

Exclusion Criteria:

• Secondary Parkinsonism, including tardive
• Concurrent dementia defined by a score lower than 22 on The Montreal Cognitive Assessment (MoCA)
• Concurrent severe depression defined by a Beck Depression Inventory-Fast Screen (BDI fast screen) score greater than 13
• Comorbidities related to sympathetic nervous system (SNS) hyperactivity
• Heart failure (LVEF <45%)
• Recent myocardial revascularization (<12 weeks)
• Hypertension (systolic blood pressure SBP>150mmHg (millimeters of mercury) or diastolic blood pressure DBP>100mmHg)
• Chronic Atrial fibrillation
• Concurrent Use of Beta-adrenergic antagonist
• Diabetes mellitus
• Chronic Obstructive Pulmonary Disease (COPD)
• Untreated Sever Sleep Apnea; Apnea-Hypopnea Index (AHI) > 30/h.
• Severely reduced kidney function (Glomerular Filtration Rate<30ml/min)
• Contraindications to the use of terazosin
• Recent myocardial infarction (<48 h)
• Ongoing angina pectoris
• Cardiogenic shock or prolonged hypotension
• Breast-feeding
• Current use of phosphodiesterase type 5 inhibitors: sildenafil (ViagraTM), tadalafil (CialisTM), or vardenafil (LevitraTM)
• History of priapism (persistent and painful erection)
• Neurogenic orthostatic hypotension defined as symptomatic decrease in BP > 20mmHg systolic or > 10mmHg diastolic and HR increase < 20bpm on supine to sitting or standing.
• Blood pressure less than 110 mm Hg systolic at screening or baseline visit
• Use of investigational drugs within 30 days before screening
• For female participant, pregnancy, or plans for child-bearing during study period
• Allergy/hypersensitivity to iodine or study medication