Efficacy of Tyrosine in Restless Legs Syndrome

Study Overview
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Brief Summary
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Tyrosine is a non essential amino acid that is the precursor of the neurotransmitter, dopamine. Tyrosine is converted into Levodihydrophenylalanine (L-Dopa) and L-Dopa is subsequently and avidly converted into dopamine. It is well known that dopamine deficiency leads to the manifestations of restless legs syndrome (RLS). Studies have shown dopamine agonists and L-dopa to be effective in controlling symptoms. No studies to date have been done to determine the role of tyrosine in RLS. This open-label pilot study aims to determine the efficacy and tolerability of tyrosine in RLS, as current agents have limitations in treating RLS in addition to adding another possible agent to the investigators arsenal of treating RLS that maybe more cost efficient. In this pilot study, the dose of tyrosine will be escalated from 750 mg once daily by mouth (PO) up to 3000 mg once daily PO, as tolerated, in increments of 750 mg every week in patients who meet the inclusion criteria for RLS. Patients' symptoms will be monitored on a weekly basis for six weeks.

Official Title
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Pilot Study of the Efficacy of Tyrosine in Restless Legs Syndrome

Conditions
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Restless Legs Syndrome (RLS)

Intervention / Treatment
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* Dietary Supplement: L-Tyrosine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women aged 18 to 80 years and Newly diagnosed (medication-naïve) as having restless legs syndrome (using the International Restless Legs Syndrome Study Group (IRLSSG20) diagnostic criteria with a score of greater than or equal to 15, see Appendix A) and That interfered with sleep onset and/or maintenance for greater than four nights/week for a minimum of six months Currently not receiving treatment for RLS Exclusion Criteria: Patients suffering from secondary RLS (other movement and/or primary sleep disorders, chronic renal insufficiency - calculated from the creatinine clearance, and/or iron deficiency - baseline serum ferritin level less than 10 ng/ml) Patients currently on pharmacotherapy for RLS (not medication-naïve) or previous use of pharmacotherapy for RLS in the past Patients that are pregnant and/or breastfeeding Patients that are on levothyroxine or monoamine oxidase inhibitors

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Tyrosine<br>Dietary Supplement: L-Tyrosine Other Names: NOW Brand L-Tyrosine 750 mg Tablets -Tyrosine 750 mg PO every day for 7 days, then increase to 1500 mg PO every day for 7 days, then increase to 2250 mg PO every day for 7 days, then increase to 3000 mg PO every day for remainder of the study. | Dietary Supplement: L-Tyrosine<br>* L-Tyrosine 750 mg PO every day for 7 days, then increase to 1500 mg PO every day for 7 days, then increase to 2250 mg PO every day for 7 days, then increase to 3000 mg PO every day for remainder of the study.<br>* Other names: NOW Brand L-Tyrosine 750 mg Tablets;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| International RLS Survey Group (IRLSSG20) Score | Use of this survey to be used as a marker for severity of RLS symptoms and therefore efficacy of this medication. | 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical global impression-global improvement (CGI-I) scale | Use of the CGI-I scale as a secondary outcome measure to determine severity of RLS symptoms and efficacy of medication. | 6 weeks | 
| Medical Outcomes Study - Sleep Scale (MOS-SS) | Use of the MOS-SS to determine severity of RLS symptoms and efficacy of medication. | 6 weeks | 
| Case Report Form | Use of a history and physical examination (limited neurological exam) to be used as a secondary assessment measure of RLS symptom severity and medication efficacy. They will be charted in case report format. | 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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RLS