Norepinephrine Transporter Blockade as a Pathological Biomarker in Neurogenic Orthostatic Hypotension

Study Overview
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Brief Summary
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The autonomic or automatic nervous system helps control blood pressure. Diseases of the autonomic nervous system may result in a drop in blood pressure on standing in many cases leading to fainting. Diseases that affect the autonomic nervous system include pure autonomic failure, multiple system atrophy and Parkinson's disease, and can present with very similar symptoms and it is sometimes difficult to determine an exact diagnosis. The purpose of the study is to find out if the blood pressure response from taking a single dose of the medication atomoxetine can help in the diagnosis of these diseases.

Detailed Description
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This is an observational, prospective three-year longitudinal study. The investigators will enroll participants with primary neurogenic orthostatic hypotension. All participants will undergo an extensive neurological and cardiovascular evaluation, including detailed autonomic testing and quality of life assessment. The investigators will then determine the magnitude of the pressor effect produced by 18 mg atomoxetine given orally, measured 1 hour after drug administration. Participants will be followed annually or more often if there is a significant change in their clinical condition. During follow up at year 3, the investigators will repeat the initial neurological, cardiovascular and autonomic evaluation. The primary endpoint would be the final diagnosis made at year 3 after the initial evaluation (at the end of the follow-up period) or if they develop significant worsening of symptoms during follow-up phone assessments, based on specific clinical criteria.

Official Title
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Norepinephrine Transporter Blockade as a Pathophysiological Biomarker in Neurogenic Orthostatic Hypotension

Conditions
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Orthostatic Hypotension, Pure Autonomic Failure, Multiple System Atrophy, Parkinson's Disease

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-80 years old with Neurogenic orthostatic hypotension, ≥30 mmHg drop in SBP within 5 minutes of standing Associated with impaired autonomic reflexes, as determined by absence of blood pressure overshoot during phase IV of the Valsalva maneuver Absence of other identifiable causes of autonomic neuropathy Able and willing to provide informed consent Exclusion Criteria: Pregnancy Systemic illnesses known to produce autonomic neuropathy, including but not limited to diabetes mellitus, amyloidosis, monoclonal gammopathy of unknown significance, and autoimmune neuropathies Known intolerance to atomoxetine, Pre-existing sustained severe hypertension (BP at least 180/110 mmHg in the sitting position) Clinically unstable coronary artery disease, or major cardiovascular or neurological event in the past 6 months Any other significant systemic, hepatic, cardiac or renal illness Use of MAO-I within 14 days Known closed-angle glaucoma or Life-threatening arrhythmias

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Neurogenic Hypotension<br>Patients with neurogenic hypotension, which includes those with Pure Autonomic Failure (PAF), Multiple System Atrophy (MSA) and Parkinson Disease (PD) | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Final Diagnosis (pre vs post ganglionic autonomic failure) based on clinical criteria. | Probable MSA - PAF with urinary incontinence or an orthostatic decrease of 30 mmHG in systolic blood pressure within 3 minutes of standing and poorly levodopa responsive parkinsonism or a cerebellar syndome. For Possible MSA - parkinsonism or a cerebellar syndrome and one additional feature. Probable PAF - orthostatic hypotension and impaired autonomic reflexes in the absence of clinical signs or symptoms of neurodegeneration. For Parkinson's Disease: diagnosed based on the United Kingdom Parkinson Disease Society Brain Bank clinical diagnostic criteria. | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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orthostatic hypotension, Multiple System Atrophy, Pure Autonomic Failure, Parkinson's Disease