The Effects of Supplementing Tyrosine on Blood Pressure in Parkinson's Disease

This study has been completed.
Sponsor:
Collaborator:
Michael J. Fox Foundation for Parkinson's Research
Information provided by (Responsible Party):
New York Institute of Technology
ClinicalTrials.gov Identifier:
NCT01676103
First received: August 28, 2012
Last updated: April 15, 2014
Last verified: April 2014
  Purpose

The objective of this experiment is:

  • Primary: To determine the effects of tyrosine supplementation on orthostatic hypotension in people with PD.
  • Secondary: To determine the effects of tyrosine supplementation in people with PD with autonomic insufficiency on HR, BP, and norepinephrine responses during acute exercise stress.

Orthostatic hypotension and autonomic abnormalities are a common problem for individuals who suffer from PD, especially as it leads to lightheadedness and falling. For those affected, it can drastically reduce quality of life. It has been hypothesized that tyrosine may impact upon individuals suffering from PD. There is ample evidence in animal models that supports our theory; however there is no clinical evidence of the impact tyrosine supplementation may have in PD patients who suffer from orthostatic hypotension and blunted BP and HR responses. Positive findings that supplemental tyrosine increases BP and HR in people with PD during daily activities such as standing up from a chair and walking can lead to new therapies to improve Parkinsonian orthostatic hypotension.

Hypothesis We will test the hypothesis that symptomatic individuals with PD on dopamine therapy who suffer from orthostatic hypotension and blunted HR and BP responses will improve after tyrosine supplementation.


Condition Intervention Phase
Parkinson's Disease
Dietary Supplement: Tyrosine
Other: Placebo Comparator:Sugar Pill
Phase 1
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Treatment
Official Title: The Effects of Supplementing Tyrosine on Blood Pressure in Parkinson's Disease

Resource links provided by NLM:


Further study details as provided by New York Institute of Technology:

Primary Outcome Measures:
  • Determine the effects of tyrosine supplementation on orthostatic hypotension in people with PD [ Time Frame: 7 days ] [ Designated as safety issue: No ]

    Orthostatic Blood Pressure Testing:

    Subjects will sit and rest for 10 minutes. Blood pressure will be taken in this resting position after the 10 minutes. Subjects will then stand upright for 3 minutes. Blood pressure will be taken every minute for those 3 minutes. A drop in systolic BP of 20 mmHg and a 10 mmHg in diastolic drop within these 3 minutes indicates orthostatic hypotension according to the American Academy of Neurology.

    Blood Samples:

    Norepinephrine and tyrosine will all be examined via blood samples drawn by a medical assistant or physician from the forearm vein in vacutainer tubes. Two vacutainers of three cc's of blood will be collected and frozen until analyzed.



Secondary Outcome Measures:
  • To determine the effects of tyrosine supplementation in people with PD with autonomic insufficiency on heart rate, blood pressure, and norepinephrine responses during acute exercise stress. [ Time Frame: 7 days ] [ Designated as safety issue: No ]

    An exercise stress test using a Modified Bruce Protocol, which consists of five 3-minute stages on a treadmill, will be used to implement acute stress. During the test, heart rate, oxygen consumption (VO2), Respiratory Exchange Ratio (RER), and 12 lead EKG tracings will be recorded at 1-minute intervals and BP and a rate of perceived exertion (RPE) will be recorded. The treadmill test will conclude when subjects attain peak exercise. Peak exercise will be determined when a subject attains any one of the following: 1) 85% of target heart rate; 2) an RPE of 8; 3) inability to maintain the pace of the treadmill; 4) an RER of over 1.3. Additionally, the American College of Sports Medicine (ACSM) guidelines for terminating exercise testing will be followed.

    Subjects will be tested on the first visit and then receive supplementation or placebo for 2x daily for 7 days. Subjects will then repeat all the tests they performed on the first visit.



Enrollment: 40
Study Start Date: September 2012
Study Completion Date: November 2013
Primary Completion Date: November 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Tyrosine
Tyrosine supplementation (500 mg 2x daily) for 7 days
Dietary Supplement: Tyrosine
Tyrosine supplementation (500 mg 2 x daily) for 7 days
Placebo Comparator: Sugar pill
Placebo sugar pills (2x daily) for 7 days
Other: Placebo Comparator:Sugar Pill
Placebo sugar pills (2x daily

  Eligibility

Ages Eligible for Study:   50 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Diagnosis of PD according to the UK Brain Bank Diagnostic criteria
  • Diagnosis of orthostatic hypotension according to EFNS guidelines
  • Able to walk on a treadmill comfortably for 6-10 minutes
  • Currently taking levodopa
  • Subjects between the age of 50-80 years old

Exclusion Criteria:

  • Currently taking an amino acid supplement
  • Currently taking medication that affects BP
  • Normal BP response to testing
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01676103

Locations
United States, New York
New York Institue of Technology
Old Westbury, New York, United States, 11568-8000
Sponsors and Collaborators
New York Institute of Technology
Michael J. Fox Foundation for Parkinson's Research
Investigators
Principal Investigator: Joanne DiFrancisco-Donoghue, PhD New York Institute of Technology
  More Information

Publications:

Responsible Party: New York Institute of Technology
ClinicalTrials.gov Identifier: NCT01676103     History of Changes
Other Study ID Numbers: BHS-797
Study First Received: August 28, 2012
Last Updated: April 15, 2014
Health Authority: United States: Institutional Review Board
United States: Food and Drug Administration

Keywords provided by New York Institute of Technology:
Parkinson's Disease (PD)
Orthostatic hypotension (OH)

Additional relevant MeSH terms:
Parkinson Disease
Parkinsonian Disorders
Basal Ganglia Diseases
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Movement Disorders
Neurodegenerative Diseases

ClinicalTrials.gov processed this record on September 14, 2014