The Pathophysiology of Orthostatic Hypotension

This study is ongoing, but not recruiting participants.
Information provided by (Responsible Party):
David Robertson, Vanderbilt University Identifier:
First received: September 5, 2008
Last updated: June 15, 2015
Last verified: December 2014
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 Intervention
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

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Screening
Official Title: The Pathophysiology of Orthostatic Hypotension

Resource links provided by NLM:

Further study details as provided by Vanderbilt University:

Primary Outcome Measures:
  • hemodynamic changes with standing [ Time Frame: following test ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • blood and urine hormones [ Time Frame: after test ] [ Designated as safety issue: No ]
  • blood volume [ Time Frame: during supine and/or upright postures ] [ Designated as safety issue: No ]
  • sympathetic nerve activity [ Time Frame: during stimulation of sympathetic nervous system ] [ Designated as safety issue: No ]
  • quantitative sweat testing [ Time Frame: 2 hours ] [ Designated as safety issue: No ]
  • Eye function [ Time Frame: once ] [ Designated as safety issue: No ]
  • Sleep efficiency [ Time Frame: once ] [ Designated as safety issue: No ]
  • Metabolic rate [ Time Frame: once ] [ Designated as safety issue: No ]
  • Pain response [ Time Frame: once ] [ Designated as safety issue: No ]
  • Responses on questionnaires and computer tasks designed to assess brain function [ Time Frame: once ] [ Designated as safety issue: No ]

Estimated Enrollment: 25
Study Start Date: December 1996
Estimated Study Completion Date: December 2015
Estimated Primary Completion Date: December 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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.


Ages Eligible for Study:   12 Years to 70 Years
Genders Eligible for Study:   Both
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
  Contacts and Locations
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Please refer to this study by its identifier: NCT00748059

United States, Tennessee
Vanderbilt University
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Vanderbilt University
Principal Investigator: David Robertson, MD Vanderbilt University
Study Director: Emily M Garland, PhD Vanderbilt University
  More Information

Additional Information:
Responsible Party: David Robertson, Professor, Vanderbilt University Identifier: NCT00748059     History of Changes
Other Study ID Numbers: 030752  HL056693 
Study First Received: September 5, 2008
Last Updated: June 15, 2015
Health Authority: United States: Food and Drug Administration

Keywords provided by Vanderbilt University:
autonomic nervous system diseases
blood pressure

Additional relevant MeSH terms:
Autonomic Nervous System Diseases
Hypotension, Orthostatic
Nervous System Diseases
Orthostatic Intolerance
Primary Dysautonomias
Cardiovascular Diseases
Neurologic Manifestations
Signs and Symptoms
Vascular Diseases
Adrenergic Agents
Adrenergic Agonists
Adrenergic Antagonists
Adrenergic alpha-1 Receptor Agonists
Adrenergic alpha-2 Receptor Agonists
Adrenergic alpha-2 Receptor Antagonists
Adrenergic alpha-Agonists
Adrenergic alpha-Antagonists
Adrenergic beta-Agonists
Adrenergic beta-Antagonists processed this record on May 26, 2016