Efficacy of Pramipexole for the Treatment of Primary Restless Leg Syndrome: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Dopamine agonists in restless leg syndrome treatment and their effects on sleep parameters: A systematic review and meta-analysis

BACKGROUND

Dopamine agonists (DAs) constitute the standard therapeutic scheme for restless leg syndrome (RLS) because they have been proven to be effective. However, DAs may change sleep parameters, thus having adverse effects on patient condition. This meta-analysis clarified the effects of DAs used in RLS treatment on the sleep architecture.

METHODS

PubMed, Embase, and Cochrane Central databases were searched for randomized control trials (RCT) (up to October 2023) that discussed the effects of DAs on sleep architecture in patients with RLS. A meta-analysis employing a random-effects model was conducted. The patients were divided into subgroups according to individual DAs and treatment duration (1 day or ≥4 weeks).

RESULTS

Thirteen eligible randomized placebo-controlled trials were included in the assessment. The effects of three DAs (i.e., pramipexole, ropinirole, and rotigotine) on rapid eye movement (REM) sleep, slow-wave sleep (SWS), and sleep efficiency (SE) were analyzed. Overall, pramipexole significantly improved SE but decreased the percentage of REM sleep among treated patients. Ropinirole also enhanced SE compared with the placebo group. Rotigotine did not affect SE and REM sleep. Subgroup analysis found that pramipexole used for 1 day and ≥4 weeks significantly diminished the percentage of REM sleep. Ropinirole used for 1 day showed similar REM sleep patterns. Finally, none of the three DAs affected SWS.

CONCLUSIONS

This meta-analysis demonstrated that DAs significantly affect sleep parameters.

Beyond Confirmed Mast Cell Activation Syndrome: Approaching Patients With Dysautonomia and Related Conditions

Allergist-immunologists face significant challenges as experts in an ever-evolving field of neuroimmunology. Among these challenges is the increasingly frequent need to counsel patients with suspected mast cell activation disorders about perceived comorbidities, which may include hypermobile Ehlers-Danlos syndrome, amplified pain syndrome, fibromyalgia, burning sensation syndromes, migraines, irritable bowel syndrome, and postural orthostatic tachycardia syndrome. Patients may experience comorbid anxiety, panic disorder, and depression associated with disturbed sleep, fatigue, and cognitive impairment that often worsen when their physical symptoms increase in severity. These conditions may mimic mast cell activation disorders and are emotionally taxing for patients and clinicians because they are often accompanied by vague diagnostic courses, perceived unmanageability, social stigma, and significant impairment in quality of life. Combined with relatively poorly researched therapies, it is no surprise that clinicians may feel overwhelmed or find it difficult to provide consistently compassionate care for this population. In this article, we review available therapies for these conditions, which run the gamut from physical therapy to antidepressants to multimodal pain control. We highlight the benefit of multidisciplinary care within the primary care home, which includes an important role by the allergist-immunologist. By outlining simple approaches to initial treatment, we hope to empower clinicians with the tools needed to curb emotional burnout and embrace this patient population with compassion.

The FDA-approved compound, pramipexole and the clinical-stage investigational drug, dexpramipexole, reverse chronic allodynia from sciatic nerve damage in mice, and alter IL-1β and IL-10 expression from immune cell culture

During the onset of neuropathic pain from a variety of etiologies, nociceptors become hypersensitized, releasing neurotransmitters and other factors from centrally-projecting nerve terminals within the dorsal spinal cord. Consequently, glial cells (astrocytes and microglia) in the spinal cord are activated and mediate the release of proinflammatory cytokines that act to enhance pain transmission and sensitize mechanical non-nociceptive fibers which ultimately results in light touch hypersensitivity, clinically observed as allodynia. Pramipexole, a D2/D3 preferring agonist, is FDA-approved for the treatment of Parkinson's disease and demonstrates efficacy in animal models of inflammatory pain. The clinical-stage investigational drug, R(+) enantiomer of pramipexole, dexpramipexole, is virtually devoid of D2/D3 agonist actions and is efficacious in animal models of inflammatory and neuropathic pain. The current experiments focus on the application of a mouse model of sciatic nerve neuropathy, chronic constriction injury (CCI), that leads to allodynia and is previously characterized to generate spinal glial activation with consequent release IL-1β. We hypothesized that both pramipexole and dexpramipexole reverse CCI-induced chronic neuropathy in mice, and in human monocyte cell culture studies (THP-1 cells), pramipexole prevents IL-1β production. Additionally, we hypothesized that in rat primary splenocyte culture, dexpramixole increases mRNA for the anti-inflammatory and pleiotropic cytokine, interleukin-10 (IL-10). Results show that following intravenous pramipexole or dexpramipexole, a profound decrease in allodynia was observed by 1 hr, with allodynia returning 24 hr post-injection. Pramipexole significantly blunted IL-1β protein production from stimulated human monocytes and dexpramipexole induced elevated IL-10 mRNA expression from rat splenocytes. The data support that clinically-approved compounds like pramipexole and dexpramipexole support their application as anti-inflammatory agents to mitigate chronic neuropathy, and provide a blueprint for future, multifaceted approaches for opioid-independent neuropathic pain treatment.

"Unvoluntary" Movement Disorders: Distinguishing between Tics, Akathisia, Restless Legs, and Stereotypies

Tics, stereotypies, akathisia, and restless legs fall at different places on the spectrum of discrete, unwanted and potentially disabling motor routines. Unlike tremor, chorea, myoclonus, or dystonia, this subgroup of abnormal movements is characterized by the subject's variable ability to inhibit or release undesired motor patterns on demand. Though it may be sometimes clinically challenging, it is crucial to distinguish these "unvoluntary" motor behaviors because secondary causes and management approaches differ substantially. To this end, physicians must consider the degree of repetitiveness of the movements, the existence of volitional control, and the association with sensory symptoms, or cognitive-ideational antecedent. This review aims to summarize the current existing knowledge on phenomenology, diagnosis, and treatment of tics, stereotypies, akathisia, and restless leg syndrome.

Insomnia - A Heterogenic Disorder Often Comorbid With Psychological and Somatic Disorders and Diseases: A Narrative Review With Focus on Diagnostic and Treatment Challenges

Patients with insomnia complain of problems with sleep onset or sleep maintenance or early morning awakenings, or a combination of these, despite adequate opportunity and circumstances for sleep. In addition, to fulfill the diagnostic criteria for insomnia the complaints need to be associated with negative daytime consequences. For chronic insomnia, the symptoms are required to be present at least 3 days per week for a duration of at least 3 months. Lastly, for insomnia to be defined as a disorder, the sleep complaints and daytime symptoms should not be better explained by another sleep disorder. This criterion represents a diagnostic challenge, since patients suffering from other sleep disorders often complain of insomnia symptoms. For instance, insomnia symptoms are common in e.g., obstructive sleep apnea and circadian rhythm sleep-wake disorders. It may sometimes be difficult to disentangle whether the patient suffers from insomnia disorder or whether the insomnia symptoms are purely due to another sleep disorder. Furthermore, insomnia disorder may be comorbid with other sleep disorders in some patients, e.g., comorbid insomnia and sleep apnea (COMISA). In addition, insomnia disorder is often comorbid with psychological or somatic disorders and diseases. Thus, a thorough assessment is necessary for correct diagnostics. For chronic insomnia disorder, treatment-of-choice is cognitive behavioral therapy, and such treatment is also effective when the insomnia disorder appears comorbid with other diagnoses. Furthermore, studies suggest that insomnia is a heterogenic disorder with many different phenotypes or subtypes. Different insomnia subtypes may respond differently to treatment, but more research on this issue is warranted. Also, the role of comorbidity on treatment outcome is understudied. This review is part of a Research Topic on insomnia launched by Frontiers and focuses on diagnostic and treatment challenges of the disorder. The review aims to stimulate to more research into the bidirectional associations and interactions between insomnia disorder and other sleep, psychological, and somatic disorders/diseases.

Effectiveness and safety of traditional Chinese medicine Shaoyao Gancao Tang for the treatment of restless leg syndrome: A protocol for systematic review and meta-analysis

BACKGROUND

A growing body of clinical trials has demonstrated that traditional Chinese medicine Shaoyao Gancao Tang may improve restlessness leg syndrome (RLS). This review aims to systematically assess its effectiveness and safety in the treatment of patients with RLS.

METHODS

Eight databases will be searched from the inception to 31 August 2020, including the Chinese Biological Medicine Database, China National Knowledge Infrastructure, Wanfang Database, VIP Information Database, the Cochrane Library, PubMed, EMBASE, and the Web of Science. All published randomized controlled trials that meet the prespecified eligibility criteria will be included. The primary outcomes include the changes in the International Restless Legs Syndrome Rating Scale and the restless sensation assessed by visual analog scales, and the secondary outcomes include effective rate, adverse event rate, quality of life measures, and improvement in the sleep quality index. Study selection, data extraction, and assessment of bias risk will be conducted independently by 2 reviewers. Data synthesis will be carried out with RevMan software (V.5.3.5). Subgroup and sensitivity analysis will be performed when necessary. The strength of the evidence will be assessed by the Grading of Recommendations Assessment, Development and Evaluation System.

RESULTS

A high-quality synthesis of current evidence of Shaoyao Gancao Tang's effectiveness and safety for patients with RLS will be provided.

CONCLUSION

This systematic review will provide evidence of whether Shaoyao Gancao Tang is an effective and safe intervention for RLS.

Classics in Chemical Neuroscience: Pramipexole

Pramipexole was first manufactured by Pharmacia and Upjohn in July 1997 under the United States brand names of Mirapex and Mirapex ER. Pramipexole is classified as a nonergoline aminobenzothiazole compound that selectively agonizes the dopamine D₂-like receptor subfamily, which includes the D₂, D₃, and D₄ receptor subtypes. Pramipexole is a unique compound in its therapeutic potential because it has D₃-preferring properties. The D₃ receptor target has implications in both motor and psychiatric symptoms of Parkinson's disease, restless leg syndrome, and bipolar and unipolar depression. Currently, pramipexole is approved to treat signs and symptoms of idiopathic Parkinson's disease and moderate to severe symptoms of primary restless leg syndrome. Parkinson's disease is characterized by tremor, bradykinesia, rigidity, gait disorders, and a disturbance of posture due to a decrease in dopamine stores in the substantia nigra with the consequent presence of Lewy bodies. Restless leg syndrome is a neurologic sensorimotor disorder characterized by a compelling urge to move the body/limb to relieve this uncomfortable sensation. In this Review, we will discuss the synthesis, drug metabolism, pharmacology, adverse effects, history, and the importance of pramipexole to neuroscience and describe its role in therapy.

Pramipexole in peritoneal dialysis patients with restless legs syndrome (RLS): a protocol for a multicentre double-blind randomised controlled trial

INTRODUCTION

Restless legs syndrome (RLS) is a common neurological sensorimotor disorder among patients with end stage renal disease. This clinical trial aimed to provide evidence on the efficacy and safety of pramipexole in patients with uremic RLS receiving peritoneal dialysis (PD).

METHODS AND ANALYSIS

This is a 12-week, multicentre, randomised, double-blind, placebo-controlled clinical trial. In total, 104 patients with uremic RLS receiving PD will be enrolled from four hospitals and randomly assigned in a 1:1 ratio to either placebo or pramipexole. We will determine the efficacy of pramipexole in the improvement of International RLS Study Group Rating Scale as the primary outcome, while responder rates for other RLS scales at week 12, change from baseline to week 12 for psychological status, sleep disorder and quality of life and blood pressure represent the secondary outcomes.

ETHICS AND DISSEMINATION

The study was approved by the ethics committees of Peking University First Hospital, Xinqiao hospital of Army Medical University, Cangzhou Center Hospital and Peking University Shenzhen Hospital. The results will be disseminated in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03817554.

Acupuncture for restless legs syndrome: A systematic review and meta-analysis protocol

BACKGROUND

Restless legs syndrome (RLS) is a neurological disorder that causes an irresistible urge to move the legs. An increasing number of studies have been published in recent years to support the effectiveness of acupuncture for RLS. We will conduct a comprehensive systematic review and meta-analysis to evaluate the evidence of randomized controlled trials for acupuncture treatment of RLS.

METHODS

The following electronic databases will be searched: PubMed, Embase, Web of Science, Cochrane Library, the China National Knowledge Infrastructure, Chinese Biomedical Literature Database, and China Science and Technology Journal Database. The range of publication time will be from the inception of the database to September 2019. Two reviewers will independently conduct article selection, data collection, and risk of bias evaluation. Any disagreement will be resolved by discussion with the third reviewer. Review Manager Software 5.3 will be used for meta-analysis. The Cochrane risk of bias tool will be used to assess the risk of bias.

RESULTS

This study will provide a high-quality evidence to assess the effectiveness and safety of acupuncture for RLS.

CONCLUSIONS

This systematic review will explore whether acupuncture is an effective and safe intervention for RLS.

REGISTRATION

PROSPERO CRD42019148948.

Pramipexole Impairs Stimulus-Response Learning in Healthy Young Adults

Dopaminergic therapy has paradoxical effects on cognition in Parkinson's disease (PD) patients, with some functions worsened and others improved. The dopamine overdose hypothesis is proposed as an explanation for these opposing effects of medication taking into account the varying levels of dopamine within different brain regions in PD. The detrimental effects of medication on cognition have been attributed to exogenous dopamine overdose in brain regions with spared dopamine levels in PD. It has been demonstrated that learning is most commonly worsened by dopaminergic medication. The current study aimed to investigate whether the medication-related learning impairment exhibited in PD patients is due to a main effect of medication by evaluating the dopamine overdose hypothesis in healthy young adults. Using a randomized, double-blind, placebo-controlled design, 40 healthy young undergraduate students completed a stimulus-response learning task. Half of the participants were treated with 0.5 mg of pramipexole, a dopamine agonist, whereas the other half were treated with a placebo. We found that stimulus-response learning was significantly impaired in participants on pramipexole relative to placebo controls. These findings are consistent with the dopamine overdose hypothesis and suggest that dopaminergic medication impairs learning independent of PD pathology. Our results have important clinical implications for conditions treated with pramipexole, particularly PD, restless leg syndrome, some forms of dystonia, and potentially depression.