Treatment of restless legs syndrome with lacosamide. Report of eight cases

Abstract

Introduction Restless Legs Syndrome (Willis-Ekbom disease) is a neurological disorder characterized by a strong urge to move the legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs; these symptoms worsen during periods of rest or inactivity, are relieved by movement and are worse during evening or night than during the day. As established by scientific evidence and guidelines, non-ergot dopaminergic agonist (DA) are the first line treatment for idiopathic RLS, alternative medications and second line treatments include antiepileptic agents (AED), opioids and benzodiazepines. Among the AED, the ligands of alpha-2 delta subunit of voltage-gated calcium channels gabapentin, gabapentin enacarbil and pregabalin, have demonstrate a therapeutic efficacy in RLS and also in neuropathic pain. RLS successful treatment is frequently limited by the partial effect of current therapies, fluctuations of the symptoms or drugs adverse effects. Lacosamide, a new anticonvulsant and neuropathic pain drug that modulates voltage-gated sodium channels, has no data about its effect in RLS to date. Materials and methods Eight idiopathic RLS patients followed up at the Hospital de la Ribera Sleep Medicine Center from 2009 to 2012, under conventional treatment with DA and/or other AED, that showed none or partial response of RLS symptoms, were treated with lacosamide. The impact of lacosamide in RLS symptoms were measured using validated scales such as Restless Legs Syndrome Rating Scale (IRLSSG-RS), before and after the lacosamide introduction. Dose adjustment and adverse effect were monitored during follow up visits. Results All results are presented as mean ±standard deviation. Time of treatment with lacosamide ranges from 4 to 36 months, (21±11.01). Single dose varies from 50 mg. to 250 mg. four patients are taking two daily doses (afternoon and evening) and three one bedtime dose. IRLSSG-RS showed a significant improvement, with pretreatment scores of 36 ±3.03, (range 32–40) and post-treatment scores of 5.16 ±4.35 (range 0–10). The mean change of score was 30.83 ±5.56 (range 25–40). In only one case lacosamide was withdrawn because no effect after 3 weeks of treatment. Conclusion Our preliminary results show that lacosamide, as other antiepileptic drugs widely studied for RLS, appears to be a reasonable option of treatment when other drugs fail or can be used as adjunctive therapy in cases of partial response.