Effect of L-Dihydroxyphenylserine (L-DOPS) on Falls in Patients With Neurogenic Orthostatic Hypotension (NOH)

Inclusion Criteria: 1. Subject has voluntarily signed and dated an informed consent form (ICF), approved by an Independent Ethics Committee (IEC)/Institutional Review Board (IRB), and provided Health Insurance Portability and Accountability Act (HIPAA) (or other applicable privacy regulation) authorization prior to any participation in the study. 2. Subject is male or female and is ≥ 30 and ≤ 83 years of age. 3. Parkinson's diagnosis with history of falls or gait difficulty. 4. Subject demonstrates neurogenic orthostatic hypotension (drop of 20 mm/Hg Systolic or 10 mm/Hg diastolic or both within 3 min of standing) 5. Fell more than once in past year. 6. Montreal Cognitive Assessment (MoCA) score ≥ 21. 7. Stable dose of levodopa, dopamine agonist, amantadine, and/or monoamine oxidase B inhibitor, i.e. unchanged for 1 month. 8. Subject is ambulatory and able to walk ≥ 10 meters with/without the use of an assistive device. Exclusion Criteria: 1. Subject has a clinical diagnosis of an atypical Parkinsonism 2. Subject has a clinical diagnosis of PD that is suspicious to the investigator as being a possible case of atypical Parkinson's 3. History of significant psychiatric illness such as schizophrenia or bipolar affective disorder or any other significant psychiatric illness that in the opinion of the investigator would interfere with participation in the study; history of major depressive disorder in the past year, or current major depressive episode 4. Patients with systolic BP ≤70 mm/hg 5. Subjects with a history of coronary artery disease or congestive heart failure 6. Participation in another investigational drug or device study in during the 60 days prior to the Screening Visit 7. Treatment with any anti-hypertensive medications 8. Treatment with any anti-spasmodic medications 9. Treatment with medications intended to elevate blood pressure 10. Treatment with non-specific monoamine oxidase (MAO) inhibitors