Could a drug for addiction help restless legs sufferers?

NCT ID NCT04145674

Symptom relief Sponsor: Mauro Manconi Source: ClinicalTrials.gov ↗

First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 1 time

Summary

This phase 2 trial tests whether d-methadone, a drug related to methadone, can ease symptoms of moderate to very severe restless legs syndrome (RLS). About 50 adults with RLS will take either d-methadone or a placebo daily for 30 days. The goal is to see if it reduces leg discomfort and improves sleep, which are major problems for people with RLS.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance: d-methadone (esmethadone, dextromethadone, REL-1017)
What this could lead to: If it works, this could point toward a new treatment option for restless legs syndrome that improves sleep and quality of life.
What could go wrong: This is a small, early-phase trial with only 50 participants. The study is currently suspended, and it's unknown if d-methadone will prove effective or safe for this condition.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2

Tests whether the treatment actually works, and watches for side effects, in a larger group.

Participants

About 50 people

The number the study aims to enrol. It can still change while the study runs.

Started

Oct 2022

Expected to finish

Dec 2026

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 75 years

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Diagnosis of primary RLS. * Moderate to very severe RLS defined as IRLS-RS score \> 10. * Written informed consent. * Willingness and ability to participate in the trial Exclusion Criteria: * Positive history of known causes of secondary RLS. * Any other concomitant treatment for RLS (wash-out period: at least 7 days). * Moderate-severe sleep apnea defined as Apnea Hypopnea Index ≥ 15. * History or presence of clinically significant abnormality as assessed by neurological examination which in the opinion of the Investigator would jeopardize the safety of the patients or the validity of the study results. * Evidence of clinically significant hepatic or renal impairment * History or family history of sudden unexplained death or long QT syndrome. * Any 12-lead ECG with demonstration of QTc ≥ 450 msec or a QRS interval ≥ 120 msec at Screening. * Concomitant use of psycho-drugs dopamine agonists and opioids (wash-out period: at least 7 days). * History or presence of any condition in which an opioid is contraindicated * History of allergy or hypersensitivity to methadone or related drugs. * Any clinically significant neurological, sleep, hepatic, renal, metabolic, hematological, immunological, cardiovascular, pulmonary, chronic pain, psychiatric or gastrointestinal disorder. * Women who are pregnant or breast feeding. * Inability to follow the procedures of the study, (e.g. due to language problems, psychological disorders, dementia, etc. of the participant). * Previous enrolment into the current study. * Enrolment of the investigator, his/her family members, employees and other dependent persons. * Participation in another study with investigational drug within the 30 days preceding and during the present study.

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Conditions

The condition(s) this trial relates to.

restless legs syndrome

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Restless legs syndrome

How to take part

Only the study team decides who joins. These are the ways to reach them.

The places running it

4 sites in 2 countries. The list below names each one and where it is.
The official record

The full official record for this study. This one lists no contact details, but it is the first place any would appear.

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A doctor treating you

A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.

Could a drug for addiction help restless legs sufferers?

What the study statuses mean