Efficacy of Tyrosine in Restless Legs Syndrome

Pilot Study of the Efficacy of Tyrosine in Restless Legs Syndrome

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.

Study Overview

• Status: Completed
• Conditions: Restless Legs Syndrome (RLS)
• Intervention / Treatment: Dietary supplement: L-Tyrosine

• Study Type: Interventional
• Enrollment (Actual): 5
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Austin, Texas, United States, 78701
      • Seton Family of Hospitals

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Men and women aged 18 to 80 years and
2. 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
3. That interfered with sleep onset and/or maintenance for greater than four nights/week for a minimum of six months
4. Currently not receiving treatment for RLS

Exclusion Criteria:

1. 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)
2. Patients currently on pharmacotherapy for RLS (not medication-naïve) or previous use of pharmacotherapy for RLS in the past
3. Patients that are pregnant and/or breastfeeding
4. Patients that are on levothyroxine or monoamine oxidase inhibitors

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Tyrosine; 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; 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.; Other Names: NOW Brand L-Tyrosine 750 mg Tablets

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Seton Healthcare Family

Study record dates

Study Major Dates

• Study Start: January 1, 2012
• Primary Completion (Actual): May 1, 2012
• Study Completion (Actual): November 1, 2012

Study Registration Dates

• First Submitted: December 15, 2011
• First Submitted That Met QC Criteria: December 16, 2011
• First Posted (Estimate): December 19, 2011

Study Record Updates

• Last Update Posted (Actual): April 27, 2017
• Last Update Submitted That Met QC Criteria: April 25, 2017
• Last Verified: April 1, 2017

More Information

Terms related to this study

• Keywords: RLS
• Additional Relevant MeSH Terms: Mental Disorders; Pathologic Processes; Nervous System Diseases; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Neurologic Manifestations; Neurobehavioral Manifestations; Disease; Dyskinesias; Psychomotor Disorders; Parasomnias; Syndrome; Psychomotor Agitation; Restless Legs Syndrome
• Other Study ID Numbers: CR-11-146