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

New York Institute of Technology

Status and phase: Completed; Phase 2; Phase 1

Conditions: Parkinson's Disease

Treatments: Other: Placebo Comparator:Sugar Pill; Dietary Supplement: Tyrosine

Study type: Interventional

Funder types: Other

Identifiers

NCT01676103

BHS-797

Details and patient eligibility

About

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.

Enrollment: 40 patients

Sex: All

Ages: 50 to 80 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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40 participants in 2 patient groups, including a placebo group

Tyrosine

Experimental group

Description:

Tyrosine supplementation (500 mg 2x daily) for 7 days

Treatment:

Dietary Supplement: Tyrosine

Sugar pill

Placebo Comparator group

Description:

Placebo sugar pills (2x daily) for 7 days

Treatment:

Other: Placebo Comparator:Sugar Pill