Long-Term Treatment of Restless Legs Syndrome (RLS): An Approach to Management of Worsening Symptoms, Loss of Efficacy, and Augmentation

Rethinking clinical trials in restless legs syndrome: A roadmap

The number of large clinical trials of restless legs syndrome (RLS) have decreased in recent years, this coincides with reduced interest in developing and testing novel pharmaceuticals. Therefore, the International Restless Legs Syndrome Study Group (IRLSSG) formed a task force of global experts to examine the causes of these trends and make recommendations to facilitate new clinical trials. In our article, we delve into potential complications linked to the diagnostic definition of RLS, identify subpopulations necessitating more attention, and highlight issues pertaining to endpoints and study frameworks. In particular, we recommend developing alternative scoring methods for more accurate RLS diagnosis, thereby improving clinical trial specificity. Furthermore, enhancing the precision of endpoints will increase study effect sizes and mitigate study costs. Suggestions to achieve this include developing online, real-time sleep diaries with high-frequency sampling of nightly sleep latency and the use of PLMs as surrogate markers. Furthermore, to reduce the placebo response, strategies should be adopted that include placebo run-in periods. As RLS is frequently a chronic condition, priority should be given to long-term studies, using a randomized, placebo-controlled, withdrawal design. Lastly, new populations should be investigated to develop targeted treatments such as mild RLS, pregnancy, hemodialysis, or iron-deficient anemia.

Cost-Effectiveness of Tonic Motor Activation (TOMAC) Therapy for Patients with Restless Legs Syndrome: An Exploratory Analysis

INTRODUCTION

Tonic motor activation (TOMAC) therapy is a novel non-pharmacologic treatment approach for patients suffering from medication-refractory restless legs syndrome (RLS). The objective of this study was to explore the potential cost-effectiveness of TOMAC in the US healthcare system.

METHODS

A decision-analytic Markov model was constructed to project strategy-specific treatment costs and benefits over 3 years and lifetime. Cohort characteristics (mean age 57.4 years, 39.8% male) and treatment effects were derived from the sham-controlled RESTFUL study. Study-observed International RLS Study Group (IRLS) scores were used to estimate changes in healthcare resource utilization and quality of life based on mapping algorithms informed by published data. The incremental cost-effectiveness ratio (ICER) was evaluated against established willingness-to-pay thresholds of $50,000/$150,000 per QALY to determine cost-effectiveness. Extensive scenario analyses were performed, including longer-term extension study data.

RESULTS

 TOMAC and sham reduced IRLS scores from baseline 25.3 to 18.10 and 21.60, respectively, at 4 weeks (treatment effect - 3.4 vs. sham), with an increase in utility from 0.80 to 0.84 (0.75-0.84 vs. baseline). Over 3 years and lifetime, the TOMAC vs. sham effect size corresponded to an added 0.10 and 0.49 QALYs (2.36 vs. 2.26; 12.59 vs. 12.10) at incremental costs of $8061 and $36,373 ($36,707 vs. $28,646; $224,040 vs.$187,667), resulting in ICER estimates of $83,822 and $73,600, respectively. Compared to baseline, TOMAC resulted in ICER estimates of $29,569 and $23,690 over 3 years and lifetime, respectively. TOMAC remained cost-effective or dominant across all scenarios, with ICERs ranging from $10,530-$83,822 and - $8061 to $29,569 vs. sham and baseline, respectively. Larger TOMAC effect sizes, achieved per extension study data, further increased cost-effectiveness.

CONCLUSION

 Based on this exploratory analysis of published trial data, TOMAC therapy appears to offer meaningful improvements in patient health-related quality at net costs that render it a cost-effective intervention. Further analyses are warranted.

A Narrative Review of the Lesser Known Medications for Treatment of Restless Legs Syndrome and Pathogenetic Implications for Their Use

Background

There are several well-known treatments for Restless Legs Syndrome (RLS), including dopamine agonists (pramipexole, ropinirole, rotigotine), anticonvulsants (gabapentin and its analogs, pregabalin), oral or intravenous iron, opioids and benzodiazepines. However, in clinical practice, treatment is sometimes limited due to incomplete response or side effects and it is necessary to be aware of other treatment options for RLS, which is the purpose of this review.

Methods

We performed a narrative review detailing all of the lesser known pharmacological treatment literature on RLS. The review purposefully excludes well-established, well-known treatments for RLS which are widely accepted as treatments for RLS in evidence-based reviews. We also have emphasized the pathogenetic implications for RLS of the successful use of these lesser known agents.

Results

Alternative pharmacological agents include clonidine which reduces adrenergic transmission, adenosinergic agents such as dipyridamole, glutamate AMPA receptor blocking agents such as perampanel, glutamate NMDA receptor blocking agents such as amantadine and ketamine, various anticonvulsants (carbamazepine/oxcarbazepine, lamotrigine, topiramate, valproic acid, levetiracetam), anti-inflammatory agents such as steroids, as well as cannabis. Bupropion is also a good choice for the treatment of co-existent depression in RLS because of its pro-dopaminergic properties.

Discussion

Clinicians should first follow evidence-based review recommendations for the treatment of RLS but when the clinical response is either incomplete or side effects are intolerable other options can be considered. We neither recommend nor discourage the use of these options, but leave it up to the clinician to make their own choices based upon the benefit and side effect profiles of each medication.

Summary

Clinicians should first follow evidence-based reviews for RLS but when response is incomplete and side effects intolerable, other medications can be considered. We do not make a recommendation on these options but leave it up to the clinician to make their own choice based upon the benefit and side effect profiles of each medication.

Consensus guidelines on the construct validity of rodent models of restless legs syndrome

Our understanding of the causes and natural course of restless legs syndrome (RLS) is incomplete. The lack of objective diagnostic biomarkers remains a challenge for clinical research and for the development of valid animal models. As a task force of preclinical and clinical scientists, we have previously defined face validity parameters for rodent models of RLS. In this article, we establish new guidelines for the construct validity of RLS rodent models. To do so, we first determined and agreed on the risk, and triggering factors and pathophysiological mechanisms that influence RLS expressivity. We then selected 20 items considered to have sufficient support in the literature, which we grouped by sex and genetic factors, iron-related mechanisms, electrophysiological mechanisms, dopaminergic mechanisms, exposure to medications active in the central nervous system, and others. These factors and biological mechanisms were then translated into rodent bioequivalents deemed to be most appropriate for a rodent model of RLS. We also identified parameters by which to assess and quantify these bioequivalents. Investigating these factors, both individually and in combination, will help to identify their specific roles in the expression of rodent RLS-like phenotypes, which should provide significant translational implications for the diagnosis and treatment of RLS.

Loss of Function in Dopamine D3 Receptor Attenuates Left Ventricular Cardiac Fibroblast Migration and Proliferation in vitro

Evidence suggests the existence of an intracardiac dopaminergic system that plays a pivotal role in regulating cardiac function and fibrosis through G-protein coupled receptors, particularly mediated by dopamine receptor 3 (D3R). However, the expression of dopamine receptors in cardiac tissue and their role in cardiac fibroblast function is unclear. In this brief report, first we determined expression of D1R and D3R both in left ventricle (LV) tissue and fibroblasts. Then, we explored the role of D3R in the proliferation and migration of fibroblast cell cultures using both genetic and pharmaceutical approaches; specifically, we compared cardiac fibroblasts isolated from LV of wild type (WT) and D3R knockout (D3KO) mice in response to D3R-specific pharmacological agents. Finally, we determined if loss of D3R function could significantly alter LV fibroblast expression of collagen types I (Col1a1) and III (Col3a1). Cardiac fibroblast proliferation was attenuated in D3KO cells, mimicking the behavior of WT cardiac fibroblasts treated with D3R antagonist. In response to scratch injury, WT cardiac fibroblasts treated with the D3R agonist, pramipexole, displayed enhanced migration compared to control WT and D3KO cells. Loss of function in D3R resulted in attenuation of both proliferation and migration in response to scratch injury, and significantly increased the expression of Col3a1 in LV fibroblasts. These findings suggest that D3R may mediate cardiac fibroblast function during the wound healing response. To our knowledge this is the first report of D3R's expression and functional significance directly in mouse cardiac fibroblasts.

Medical Case Report on Repeat Treatment of Restless Legs Syndrome with Intravenous Infusion of Iron

Restless legs syndrome (RLS) is a debilitating neurological disorder for which a range of medical interventions with varied efficacy has been employed. Based on evidence of iron deficiency in the substantia nigra of the midbrain, there are reports of substantial benefits from intravenous iron infusion. This case report demonstrates a strong statistically significant negative correlation between serum ferritin and RLS severity of symptoms in a subject with RLS who received 2 intravenous infusions of ferric carboxymaltose over a period of 464 days. The results provide further evidence to support the treatment strategy.

Restless Legs Syndrome: Challenges to Treatment

For a long time, dopaminergic treatment (DT) was the medication for restless legs syndrome. Although DT is effective and safe over the short-term, complications develop over longer periods, including augmentation, tolerance, and impulse control disorders. Nowadays, it is recommended that first-line treatment should be alpha-2 ligands, which are more effective in the absence of previous DT. As a second-line treatment, opioids, such as oxycodone extended-release with naloxone, are approved in Europe. Brain iron should be monitored before and during treatment and corrected if necessary. Two new promising non-DTs are being developed: perampanel and dipyridamole. More research is needed.

Baseline and 1-year longitudinal data from the National Restless Legs Syndrome Opioid Registry

STUDY OBJECTIVES

Restless legs syndrome (RLS) is a sensory-motor neurological disorder. Low dose opioid medications are prescribed for treatment-refractory RLS. We describe baseline and 1-year longitudinal dosing and symptom outcomes for the National RLS Opioid Registry.

METHODS

Individuals currently taking a prescribed opioid for diagnosed RLS are included in the registry. Information on initial and current opioid dosages, side effects, past and current concomitant RLS treatments, RLS severity, psychiatric history, and opioid abuse risk factors were collected at baseline. Follow-up online surveys were performed at 6 months and 1-year.

RESULTS

Participants (n = 500) are primarily white, elderly, educated, and retired. Half of all subjects are on opioid monotherapy. Nearly 50% of all subjects are taking methadone, and one-quarter are taking oxycodone formulations. The median total daily opioid dose is 30.0 morphine milligram equivalents (MME). At baseline, three-quarters of registry participants had been taking a prescribed opioid for RLS for more than 1 year and one-third for more than 5 years, and had mild-moderate RLS symptoms. At 1-year follow-up, 31.2% increased dose (median = 10 MME) and 16.0% decreased dose of their opioid. An MME increase ≥25 was associated with: opioid use for non-RLS pain, <1 year of opioid use, opioid switch to methadone, and discontinuation of non-opioid RLS medications which, combined, accounted for 91.7% of those with 1-year follow-up increases ≥25 MME.

CONCLUSIONS

In refractory RLS, prescribed opioids are generally used at low doses with good efficacy. Longitudinally over 1 year, roughly one-third of participants increased their prescribed opioid dose, though generally by small amounts, with larger dose increases accounted for by predictable features.

Current Evidence on Diagnostic Criteria, Relevant Outcome Measures, and Efficacy of Nonpharmacologic Therapy in the Management of Restless Legs Syndrome (RLS): A Scoping Review

OBJECTIVE

The aim of this scoping review is to outline the current evidence regarding the management of restless legs syndrome (RLS) with nonpharmacologic approaches. To categorize the efficacy of conservative approaches in reducing symptoms of RLS, we have identified and summarized the current data regarding diagnostic criteria and relevant outcome measures, to inform future research and to guide clinical practice.

METHODS

A scoping review was conducted using the National Center for Biotechnology Information; EBSCO; the Manual, Alternative and Natural Therapy Index System; the Cumulative Index to Nursing & Allied Health Literature; and Scopus. All literature related to RLS was extracted, screened, and reviewed based on titles and abstract contents. The authors then extracted data from the 24 admissible studies, that is, the ones about manual therapy, exercises, and alternative treatments for RLS. The Physiotherapy Evidence Database scale was used to rate the methodological quality of the included randomized controlled trials by 2 independent readers.

RESULTS

In the 24 articles fulfilling the selection criteria, there was a consistent trend in the findings showing positive results in lowering RLS symptom severity. Most clinical studies based their diagnosis on the International Restless Legs Syndrome Study Group diagnostic criteria; the International Restless Legs Syndrome Study Group rating scale was the most often used outcome measure. The efficacy of exercise, yoga, massage, acupuncture, traction straight leg raise, cryotherapy, pneumatic compression devices, whole-body vibration, transcranial and transcutaneous stimulation, and near-infrared lights showed different effects on RLS symptom severity, and the level of evidence was evaluated.

CONCLUSION

Our results showed clinically significant effects for exercises, acupuncture, pneumatic compression devices, and near-infrared light. Short-lasting effects were identified with whole-body cryotherapy, repetitive transcranial stimulation, and transcutaneous stimulation. More studies are necessary to investigate efficacy of yoga, massage, traction straight leg raise, and whole-body vibration. No adverse effects were identified for moderate-intensity exercise, yoga, massage, and pneumatic compression devices.

Restless Leg Syndrome in the Setting of Patients With End-Stage Renal Disease on Hemodialysis: A Literature Review

Restless Leg Syndrome (RLS), or Willis-Ekbom disease (WED), is an irresistible urge to move the legs, predominantly while resting, sitting, or sleeping, which disrupts sleep and impairs quality of life. RLS can occur secondary to uremia in chronic kidney disease (CKD) patients due to inadequate hemodialysis. Early diagnosis is essential to prevent muscular atrophy and to improve the quality of life of RLS patients, especially those with end-stage renal disease (ESRD). Cardiac mortality high in uremic RLS patients due to associated discomfort and lowering the duration of hemodialysis treatment. This review focuses on and discusses the diagnosis, treatment, and associated comorbid conditions of uremic RLS. Though the exact pathophysiology is unknown, altered transferrin expression in the choroid plexus, increased glutamate levels in the thalamus, decreased opioid receptors, dopamine system dysfunction, calcium/phosphate imbalance, and single nucleotide polymorphisms in the BTBD9 and MEIS1 genes are a few nonconfirmatory pathophysiological concepts for uremic RLS. Nonpharmacological options include lowering the temperature of dialysate by 1 degree C and home-based therapies like massages, warm/cold baths, and aerobic exercises. Pharmacological therapy like dopamine agonists ropinirole and pramipexole reduces the symptoms effectively. However, surgical options like parathyroidectomy and renal transplantation are stated as the best treatment options in patients suffering from uremic RLS.

An update on the treatment of Restless Legs Syndrome/Willis-Ekbom Disease: prospects and challenges

INTRODUCTION

Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a sleep disorder characterized by an urge to move the legs, frequently associated or triggered by unpleasant sensations in the lower limbs that affects approximately 2.5% of adults. Therapy and management of RLS/WED require long-term interventions, since the typical manifestation of this disorder is chronic. Areas covered: In this review, we provide an update regarding the treatment of RLS/WED with particular attention to future challenges for its management. We reviewed a large variety of treatments studied in clinical trials and supported by the most updated guidelines. Alongside with first-line interventions other pharmacological options including opioids, benzodiazepines, iron therapy, and newly studied drugs are discussed. Furthermore, due to the occurrence of augmentation and worsening of symptoms we also reviewed the development of non-pharmacologic alternatives. Expert commentary: The management of RLS/WED is a challenge because of different long-term issues. Several complications, such as loss of the therapeutic effect of dopaminergic or non-dopaminergic agents and augmentation, are still unsolved concerns. However, the development of new drugs acting on adenosinergic and glutamatergic neurotransmission seems promising. Randomized controlled trials are needed in order to recognize effectiveness of new drugs or non-pharmacological treatment strategies.

Prevalence of restless legs symptoms according to depressive symptoms and depression type: a cross-sectional study

BACKGROUND

Restless legs syndrome is a sensorimotor disorder and it is associated with several other diseases especially mental illnesses.

AIMS

To analyze the relationship between the symptoms of restless legs syndrome and the severity of depressive symptoms and the prevalence of restless legs symptoms in depression subtypes.

METHODS

A cross-sectional study of primary care patients in the Central Finland Hospital District. The prevalence of restless legs symptoms was studied in 706 patients with increased depressive symptoms and 426 controls without a psychiatric diagnosis by using a structured questionnaire. The depressive symptoms were evaluated with the Beck Depression Inventory (BDI) and the psychiatric diagnosis was confirmed by means of a diagnostic interview (Mini-International Neuropsychiatric Interview). The subjects with increased depressive symptoms were divided into three groups (subjects with depressive symptoms without a depression diagnosis, melancholic depression and non-melancholic depression).

RESULTS

In the whole study population, the prevalence of restless legs symptoms increased with the severity of depressive symptoms. The prevalence of restless legs symptoms was highest in the melancholic and non-melancholic depressive patients (52 and 46%, respectively) and then in subjects with depressive symptoms without a depression diagnosis (43.4%), but the prevalence was also substantial (24.6%) in subjects without a psychiatric diagnosis.

CONCLUSIONS

Restless legs symptoms are very common in primary care among subjects with depression, regardless of the depression type. The prevalence of restless legs symptoms increased with increasing severity of depressive symptoms, regardless of the diagnosis. These findings should be considered in clinical evaluation and treatment of patients visiting their physician due to restless legs or depressive symptoms.

Restless Legs Syndrome: From Pathophysiology to Clinical Diagnosis and Management

Restless legs syndrome (RLS), a common neurological sensorimotor disorder in western countries, has gained more and more attention in Asian countries. The prevalence of RLS is higher in older people and females. RLS is most commonly related to iron deficiency, pregnancy and uremia. The RLS symptoms show a significant circadian rhythm and a close relationship to periodic limb movements (PLMs) in clinical observations, while the pathophysiological pathways are still unknown. The diagnostic criteria have been revised in 2012 to improve the validity of RLS diagnosis. Recent studies have suggested an important role of iron decrease of brain in RLS pathophysiology. Dopaminergic (DA) system dysfunction in A11 cell groups has been recognized long ago from clinical treatment and autopsy. Nowadays, it is believed that iron dysfunction can affect DA system from different pathways and opioids have a protective effect on DA system. Several susceptible single nucleotide polymorphisms such as BTBD9 and MEIS1, which are thought to be involved in embryonic neuronal development, have been reported to be associated with RLS. Several pharmacological and non-pharmacological treatment are discussed in this review. First-line treatments of RLS include DA agents and α2δ agonists. Augmentation is very common in long-term treatment of RLS which makes prevention and management of augmentation very important for RLS patients. A combination of different types of medication is effective in preventing and treating augmentation. The knowledge on RLS is still limited, the pathophysiology and better management of RLS remain to be discovered.

Guidelines for the first-line treatment of restless legs syndrome/Willis-Ekbom disease, prevention and treatment of dopaminergic augmentation: a combined task force of the IRLSSG, EURLSSG, and the RLS-foundation

A Task Force was established by the International Restless Legs Syndrome Study Group (IRLSSG) in conjunction with the European Restless Legs Syndrome Study Group (EURLSSG) and the RLS Foundation (RLS-F) to develop evidence-based and consensus-based recommendations for the prevention and treatment of long-term pharmacologic treatment of dopaminergic-induced augmentation in restless legs syndrome/Willis-Ekbom disease (RLS/WED). The Task Force made the following prevention and treatment recommendations: As a means to prevent augmentation, medications such as α2δ ligands may be considered for initial RLS/WED treatment; these drugs are effective and have little risk of augmentation. Alternatively, if dopaminergic drugs are elected as initial treatment, then the daily dose should be as low as possible and not exceed that recommended for RLS/WED treatment. However, the physician should be aware that even low dose dopaminergics can cause augmentation. Patients with low iron stores should be given appropriate iron supplementation. Daily treatment by either medication should start only when symptoms have a significant impact on quality of life in terms of frequency and severity; intermittent treatment might be considered in intermediate cases. Treatment of existing augmentation should be initiated, where possible, with the elimination/correction of extrinsic exacerbating factors (iron levels, antidepressants, antihistamines, etc.). In cases of mild augmentation, dopamine agonist therapy can be continued by dividing or advancing the dose, or increasing the dose if there are breakthrough night-time symptoms. Alternatively, the patient can be switched to an α2δ ligand or rotigotine. For severe augmentation the patient can be switched either to an α2δ ligand or rotigotine, noting that rotigotine may also produce augmentation at higher doses with long-term use. In more severe cases of augmentation an opioid may be considered, bypassing α2δ ligands and rotigotine.

Treatment Options in Intractable Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED)

OPINION STATEMENT

Restless Legs Syndrome/Willis-Ekbom Disease (RLS/WED) is a common condition characterized by an irresistible urge to move the legs, concomitant with an unpleasant sensation in the lower limbs, which is typically relieved by movement. Symptoms occur predominantly at rest and prevail in the afternoon or evening. Treatment of patients with RLS/WED is indicated for those patients who suffer from clinically relevant symptoms. The management of mild forms of RLS/WED is mainly based on dopamine agonists (DA) therapy (including pramipexole and ropinirole) and α-2-δ calcium-channel ligand. Nevertheless, with passing of time, symptoms tend to become more severe and the patient can eventually develop pharmacoresistance. Furthermore, long-term treatment with dopaminergic agents may be complicated by the development of augmentation, which is defined by an increase in the severity and frequency of RLS/WED symptoms despite adequate treatment. Here, we discuss which are the best therapeutic options when RLS/WED becomes intractable, with a focus on advantages and side effects of the available medications. Prevention strategies include managing lifestyle changes and a good sleep hygiene. Different drug options are available. Switching to longer-acting dopaminergic agents may be a possibility if the patient is well-tolerating DA treatment. An association with α-2-δ calcium-channel ligand is another first-line approach. In refractory RLS/WED, opioids such as oxycodone-naloxone have demonstrated good efficacy. Other pharmacological approaches include IV iron, benzodiazepines such as clonazepam, and antiepileptic drugs, with different level of evidence of efficacy. Therefore, the final decision regarding the agent to use in treating severe RLS/WED symptoms should be tailored to the patient, taking into account the symptomatology, comorbidities, the availability of treatment and the history of the disease.