Restless legs syndrome induced by topiramate: Two more cases

Anticonvulsant Agents for Treatment of Restless Legs Syndrome: A Case Report With Lamotrigine and a Review of the Literature

INTRODUCTION

Restless Legs Syndrome (RLS) is a neurological disorder primarily treated with pregabalin and gabapentin, followed by dopamine agonists later in the process due to the risk of augmenting RLS symptoms. In addition, clinical reports have disclosed varying degrees of success employing other agents in patients unresponsive to traditional agents. Here, we present a patient who had success in the reduction of RLS symptoms with lamotrigine, a broad-spectrum anticonvulsant. Previously, lamotrigine had been used in 2 trials with successful treatment of RLS.

CASE REPORT

We present a 58-year-old right-handed lady with long-standing history of smoking, hypertension, dyslipidaemia, prediabetes, gastro-esophageal reflux disease, asthma, strabismus, uterine cancer, severe and debilitating course of RLS accompanied by unexplained deterioration. The patient initially demonstrated abnormal sensation in all her limbs, which worsened with radiotherapy treatment, and was eventually diagnosed with RLS based on the diagnostic criteria. Subsequent examinations were unremarkable and revealed no further explanation for the deterioration of the RLS symptoms. While the complexity of the patient's medical history had exposed her to a variety of medications, she reported that only lamotrigine, in addition to her original regimen of methadone and pramipexole, offered significant symptomatic relief. It must be noted that no adverse side effects, including impulse-control disorder, were reported by the patient.

CONCLUSIONS

We present a case of a woman whose deteriorating symptoms of RLS were successfully alleviated by the administration of lamotrigine. This is only the third case in the literature to have successfully utilized lamotrigine as a treatment option for RLS.

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.

Antiseizure Drugs and Movement Disorders

The relationship between antiseizure drugs and movement disorders is complex and not adequately reviewed so far. Antiseizure drugs as a treatment for tremor and other entities such as myoclonus and restless leg syndrome is the most common scenario, although the scientific evidence supporting their use is variable. However, antiseizure drugs also represent a potential cause of iatrogenic movement disorders, with parkinsonism and tremor the most common disorders. Many other antiseizure drug-induced movement disorders are possible and not always correctly identified. This review was conducted by searching for all the possible combinations between 15 movement disorders (excluding ataxia) and 24 antiseizure drugs. The main objective was to describe the movement disorders treated and worsened or induced by antiseizure drugs. We also summarized the proposed mechanisms and risk factors involved in the complex interaction between antiseizure drugs and movement disorders. Antiseizure drugs mainly used to treat movement disorders are clonazepam, gabapentin, lacosamide, levetiracetam, oxcarbazepine, perampanel, phenobarbital, pregabalin, primidone, topiramate, and zonisamide. Antiseizure drugs that worsen or induce movement disorders are cenobamate, ethosuximide, felbamate, lamotrigine, phenytoin, tiagabine, and vigabatrin. Antiseizure drugs with a variable effect on movement disorders are carbamazepine and valproate while no effect on movement disorders has been reported for brivaracetam, eslicarbazepine, lacosamide, and stiripentol. Although little information is available on the adverse effects or benefits on movement disorders of newer antiseizure drugs (such as brivaracetam, cenobamate, eslicarbazepine, lacosamide, and rufinamide), the evidence collected in this review should guide the choice of antiseizure drugs in patients with concomitant epilepsy and movement disorders. Finally, these notions can lead to a better understanding of the mechanisms involved in the pathophysiology and treatments of movement disorders.

Movement disorders associated with antiseizure medications: A systematic review

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.

Expert Opinion: Managing sleep disturbances in people with epilepsy

Poor sleep and daytime sleepiness are common in people with epilepsy. Sleep disorders can disrupt seizure control and in turn sleep and vigilance problems can be exacerbated by seizures and by antiepileptic treatments. Nevertheless, these aspects are frequently overlooked in clinical practice and a clear agreement on the evidence-based guidelines for managing common sleep disorders in people with epilepsy is lacking. Recently, recommendations to standardize the diagnostic pathway for evaluating patients with sleep-related epilepsies and comorbid sleep disorders have been presented. To build on these, we adopted the Delphi method to establish a consensus within a group of experts and we provide practical recommendations for identifying and managing poor night-time sleep and daytime sleepiness in people with epilepsy. We recommend that a comprehensive clinical history of sleep habits and sleep hygiene should be always obtained from all people with epilepsy and their bed partners. A psychoeducational approach to inform patients about habits or practices that may negatively influence their sleep or their vigilance levels should be used, and strategies for avoiding these should be applied. In case of a suspected comorbid sleep disorder an appropriate diagnostic investigation should be performed. Moreover, the possible presence of sleep fragmentation induced by sleep-related seizures should be ruled out. Finally, the dose and timing of antiepileptic medications and other co-medications should be optimized to improve nocturnal sleep and avoid daytime sedation.

Restless legs-like syndrome as an emergent adverse event of CGRP monoclonal antibodies: A report of two cases

BACKGROUND

One of the advantages of CGRP monoclonal antibodies is their excellent safety and tolerability. However, postmarketing surveillance, is essential to detect potential rare emergent adverse events.

OBJECTIVES

To report two patients who developed restless legs syndrome symptoms after treatment with CGRP antibodies.

METHODS AND RESULTS

Two women with chronic refractory migraine, with no significant medical antecedents, developed typical restless legs syndrome symptoms 1.5 and 4 months after starting erenumab 140 mg, respectively. In case 1 symptoms resolved when erenumab was stopped for two months but reappeared on galcanezumab. In both patients migraine attacks had dramatically decreased and no iron deficiency was found.

CONCLUSIONS

Even though caution is needed before establishing a causal relationship, these cases suggest that restless legs-like symptoms might be an emergent adverse event of CGRP antibodies, regardless of the mechanism of action. We propose that plastic changes in CGRP sensory fibers, which are very abundant in legs, induced by CGRP monoclonal antibodies could be the reason for restless legs syndrome development.

Topiramate-Associated Movement Disorder: Case Series and Literature Review

BACKGROUND

Topiramate (TPM) is a fructose derivative, which was originally developed as an antiepileptic. In this context, movement disorders (MDs) are possible adverse events secondary to TPM.

CASE REPORTS

Two patients (cases 1 and 2) developed myoclonus, and the other 2 had restless leg syndrome (RLS, cases 3 and 4). The mean age of the individuals (3 female patients) was 45.75 ± 21.28 years. All the individuals had a negative family history for movement and psychiatry disorders. Topiramate was started at 25 mg with a gradual increase of 25 mg every week. The mean time of onset and recovery of the MD were 1.37 ± 1.10 and 1.02 ± 0.77 months, respectively. The mean TPM dose was 87.5 ± 47.87 mg. Individual 1 presented with upper and lower limb jerks; individual 2 only with upper limb involvement. Individuals 3 and 4 experienced insomnia and nocturnal leg discomfort during inactivity with an urge to move the legs, which they denied having previously; the RLS symptoms occurred within approximately 1 to 3 hours of TPM evening dose. On neurological examination, no tremor or bradykinesia was observed; deep tendon reflexes, sensory examination, and strength were normal and preserved. Laboratory tests, neuroimaging, and electromyography were within normal. Topiramate was discontinued in all of the subjects. Full recovery was obtained in all cases.

CONCLUSIONS

To the authors' knowledge, there are 6 cases of myoclonus, 5 RLS, 2 dystonia, 1 dyskinesia, and 1 periodic limb MD. The best management is probably the discontinuation of TPM, but in RLS patients, the addition of a dopaminergic agonist can be beneficial.

Drug-Induced Restless Legs Syndrome

OBJECTIVE

To review the literature on drug-induced restless legs syndrome (DI-RLS).

DATA SOURCES

The review included a search for English-language literature from 1966 to December 2017 in the MEDLINE, PubMed, and Ovid databases using the following search terms: restless legs syndrome (RLS), periodic limb movement, adverse effects, and drug-induced. In addition, background articles on the pathophysiology, etiology, and epidemiology of RLS were retrieved. Bibliographies of relevant articles were reviewed for additional citations.

STUDY SELECTION AND DATA EXTRACTION

All case reports, case series, and review articles of DI-RLS were identified and analyzed. There were only a small number of controlled clinical trials, and most data were from case reports and case series.

RESULTS

Several drugs and drug classes have been implicated in DI-RLS, with antidepressants, antipsychotics, and antiepileptics having the most evidence. In addition, RLS may be linked with a number of disorders or underlying predisposing factors as well.

CONCLUSIONS

The prevalence of RLS is variable and ranges from 3% to 19% in the general population. There are many predisposing factors to RLS, but an emerging body of evidence suggests that there is an association between numerous drugs and RLS.

Topiramate-induced periodic limb movement disorder in a patient affected by focal epilepsy

Periodic limb movement disorder (PLMD) is characterized by pathological periodic limb movements during sleep, insomnia and/or diurnal sleepiness, and the absence of another primary sleep disorder. We report a patient with complex partial seizures who developed PLMD while taking topiramate (TPM). He had no evidence of metabolic and/or other conditions inducing PLMD. He also had fragmented sleep and disruptive PLMS on polysomnography, and PLMS subsided with change of antiepileptic drug. Topiramate may modulate the dopaminergic pathway by inhibition of glutamate release, thereby inducing PLMD as observed in our patient. Although a single case does not allow any generalization, PLMD should be considered in patients complaining of insomnia and treated with TPM.

What's the role of topiramate in the management of patients with hyperkinetic movement disorders?

Topiramate (TPM) is an O-alkyl sulfamate derivative of the naturally occurring monosaccharide D-fructose with an epileptic activity. However, it has been suggested that, in addition to its use in epilepsy, TPM could also be used in the treatment of neurological disorders, psychiatric conditions and hyperkinetic movement disorders. The clinical applications of TPM in hyperkinetic movement disorders is consistent with the multiple pharmacodynamic mechanisms e.g., the modulation of both γ-aminobutyric acidergic or glutamatergic neurotransmission and the modulation of voltage-gated ion channels or intracellular signalling pathways. The purpose of the present review is to describe the mechanisms of action of TPM and its clinical efficacy in patients with hyperkinetic movement disorders.