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The Pathophysiology of Orthostatic Hypotension

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00748059
Recruitment Status : Active, not recruiting
First Posted : September 8, 2008
Last Update Posted : January 10, 2019
Information provided by (Responsible Party):
Emily M. Garland, Vanderbilt University Medical Center

Brief Summary:
The purpose of this study is to determine the cause of low blood pressure in selective patients who have problems with their involuntary (autonomic) nervous system. These patients frequently have had symptoms throughout their life, and their disorder might have a genetic basis. The biochemical, physiological and pharmacological procedures in this study should help us define the problem and perhaps lead to more effective treatment.

Condition or disease Intervention/treatment Phase
Autonomic Nervous System Diseases Orthostatic Hypotension Dopamine Beta-Hydroxylase Deficiency Orthostatic Intolerance Procedure: Standing or upright tilt Procedure: Microneurography Procedure: QSweat Device: neck cuff stimulation Drug: phenylephrine,isoproterenol,nitroprusside,propranolol,edrophonium,atropine,tyramine Drug: clonidine,yohimbine,metoclopramide,alpha-methyldopa Procedure: BodPod Procedure: Eye exam Procedure: Sleep study Procedure: Pain response testing Procedure: Metabolic chamber Procedure: Brain function studies Procedure: Bicycle Exercise Test Phase 1

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 25 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Screening
Official Title: The Pathophysiology of Orthostatic Hypotension
Study Start Date : December 1996
Estimated Primary Completion Date : December 2020
Estimated Study Completion Date : December 2020

Arm Intervention/treatment
Experimental: A
Patients with Orthostatic Hypotension
Procedure: Standing or upright tilt
stand upright or tilt table test

Procedure: Microneurography
Recording from sympathetic nerve

Procedure: QSweat
quantitative sweat testing

Device: neck cuff stimulation
Blood pressure receptors in the neck arteries may be stimulated by applying suction through a collar around the neck.

Drug: phenylephrine,isoproterenol,nitroprusside,propranolol,edrophonium,atropine,tyramine

IV Pharmacological Testing

phenylephrine 12.5 - 400 ug, isoproterenol 0.1 - 0.4 ug or higher until desired effect, nitroprusside 0.1 - 1.6 ug/kg, propranolol 1.1 mg/min, edrophonium maximum of 10 mg, atropine .01 mg/kg, tyramine 250-4000 ug or higher until desired effect

Drug: clonidine,yohimbine,metoclopramide,alpha-methyldopa

Oral Pharmacological Testing

clonidine 0.1-0.3 mg, yohimbine 5-10 mg, metoclopramide 10 mg, alpha-methyldopa 62.5 mg, placebo

Procedure: BodPod
Determination of body composition

Procedure: Eye exam

Examination of pressure in the eye and eyelid fatiguability. The following eyedrops might be used:

  1. 0.5% proparacaine (Alcaine, Allergan, Inc)
  2. Fluress (0.4% benoxinate hydrochloride, fluorescein sodium, Akorn, Inc)
  3. 0.5%, 1% tropicamide (Mydriacyl, Alcon)
  4. Over-the-counter preservative-free artificial tears
  5. 0.25%, 2.5% and 10% phenylephrine (Bausch and Lomb)
  6. 1% cyclopentolate hydrochloride (Alcon)

Procedure: Sleep study
Recording of sleep pattern overnight

Procedure: Pain response testing
Subjects will rate the quality and intensity of 2 pain tasks.

Procedure: Metabolic chamber
Determination of metabolic rate via 24hr stay in whole-room indirect calorimeter

Procedure: Brain function studies
Questionnaires and computer tasks, an EEG and an MRI may be used to assess brain function.

Procedure: Bicycle Exercise Test
Blood pressure and heart rate may be monitored while exercising on a stationary bicycle.

Primary Outcome Measures :
  1. hemodynamic changes with standing [ Time Frame: following test ]

Secondary Outcome Measures :
  1. blood and urine hormones [ Time Frame: after test ]
  2. blood volume [ Time Frame: during supine and/or upright postures ]
  3. sympathetic nerve activity [ Time Frame: during stimulation of sympathetic nervous system ]
  4. quantitative sweat testing [ Time Frame: 2 hours ]
  5. Eye function [ Time Frame: once ]
  6. Sleep efficiency [ Time Frame: once ]
  7. Metabolic rate [ Time Frame: once ]
  8. Pain response [ Time Frame: once ]
  9. Responses on questionnaires and computer tasks designed to assess brain function [ Time Frame: once ]

Information from the National Library of Medicine

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Ages Eligible for Study:   12 Years to 70 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • severe orthostatic hypotension and other autonomic symptoms but do not meet criteria for standard diagnosis
  • non-smokers
  • drug-free
  • able to give informed consent
  • free of pulmonary, renal, hematopoietic, hepatic and cardiac disease

Exclusion Criteria:

  • medications affecting the autonomic nervous system
  • any chronic illness
  • anemia (Hct<30)
  • women of childbearing age who are pregnant or nursing
  • smokers

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00748059

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United States, Tennessee
Vanderbilt University
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Vanderbilt University Medical Center
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Principal Investigator: Emily M Garland, PhD Vanderbilt University

Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Emily M. Garland, Research Associate Professor, Vanderbilt University Medical Center Identifier: NCT00748059     History of Changes
Other Study ID Numbers: 030752
First Posted: September 8, 2008    Key Record Dates
Last Update Posted: January 10, 2019
Last Verified: January 2019
Keywords provided by Emily M. Garland, Vanderbilt University Medical Center:
autonomic nervous system diseases
blood pressure
Additional relevant MeSH terms:
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Hypotension, Orthostatic
Orthostatic Intolerance
Autonomic Nervous System Diseases
Primary Dysautonomias
Nervous System Diseases
Vascular Diseases
Cardiovascular Diseases
Neurologic Manifestations
Signs and Symptoms
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents