Bilateral high-frequency noninvasive peroneal nerve stimulation evokes tonic leg muscle activation for sleep-compatible reduction of restless legs syndrome symptoms.

STUDY OBJECTIVES: Restless legs syndrome (RLS) is a prevalent sleep disorder with limited treatment options. Bilateral high-frequency noninvasive peroneal nerve stimulation (NPNS) reduces RLS symptoms. Here, we sought to characterize the mechanism of action for NPNS and identify predictors of treatment response. We hypothesized that, similar to voluntary leg movements, NPNS reduces RLS symptoms by activating leg muscles. METHODS: For 20 adults with moderate-severe RLS, we tested this hypothesis by recording surface electromyography (EMG) from the tibialis anterior leg muscle while administering NPNS at varying amplitudes to determine the minimum NPNS amplitude that evoked EMG activity (motor threshold) and maximal NPNS amplitude that was not distracting (therapeutic intensity level). Afterwards, participants self-administered NPNS (at the therapeutic intensity level) and sham control for 14 days, each in randomized order. Efficacy was defined as International RLS Study Group Rating Scale (IRLS) score difference for NPNS compared with sham. RESULTS: NPNS consistently activated leg muscles; NPNS evoked EMG activity at the therapeutic intensity level for 19 of 20 participants (mean TIL: 26.6 mA, mean MT: 18.3 mA). Evoked EMG activity was tonic (not phasic) and sustained over time. Evoked EMG activity predicted efficacy; participants with lower motor thresholds had greater IRLS improvement (r = .45, P = .046). NPNS treatment did not interfere with self-reported sleep onset (NPNS: 16% of nights; sham: 11%; P = .629) and frequently improved self-reported sleep onset (NPNS: 52% of nights; sham: 15%; P = .002). CONCLUSIONS: These results demonstrate that NPNS reduces RLS symptoms by activating afferent pathways, thereby generating tonic and sustained leg muscle activity without interfering with sleep. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Noninvasive Peripheral Nerve Stimulation for Restless Legs Syndrome; URL: https://clinicaltrials.gov/ct2/show/NCT04700683; Identifier: NCT04700683. CITATION: Charlesworth JD, Adlou B, Singh H, Buchfuhrer MJ. Bilateral high-frequency noninvasive peroneal nerve stimulation evokes tonic leg muscle activation for sleep-compatible reduction of restless legs syndrome symptoms. J Clin Sleep Med. 2023;19(7):1199-1209.

Solriamfetol Titration & AdministRaTion (START) in Patients With Narcolepsy.

PURPOSE: Solriamfetol, a dopamine/norepinephrine reuptake inhibitor, is approved (in the United States and European Union) to treat excessive daytime sleepiness (EDS) in adults with narcolepsy (75-150 mg/d) or obstructive sleep apnea (OSA) (37.5-150 mg/d). This study characterized real-world titration strategies for patients with narcolepsy (with or without comorbid OSA) initiating solriamfetol therapy. METHODS: This virtual, descriptive study included a retrospective medical record review and qualitative survey. US-based physicians prescribing solriamfetol for EDS associated with narcolepsy or OSA participated. Data are reported for patients with narcolepsy with or without comorbid OSA (OSA alone reported separately). On the basis of medical record review, titration strategies were classified de novo (EDS medication naive), transition (switched or switching from existing EDS medication[s] to solriamfetol), or add-on (adding solriamfetol to current EDS medication[s]). The survey included open-ended questions regarding a hypothetical patient-a 32-year-old woman with narcolepsy (Epworth Sleepiness Scale score of 8) treated with 35 mg/d of amphetamine and 6 g per night of sodium oxybate who experiences non-use-limiting adverse events from amphetamine. FINDINGS: Twenty-six physicians participated: 23 provided data from 70 patients with narcolepsy (type 1, n = 24; type 2, n = 46; mean [SD] age, 40 [11] years; 57% female; 6 with comorbid OSA), and 26 responded to the hypothetical patient scenario. From the medical record review, solriamfetol therapy initiation was de novo for 19 of 70 patients (27%), transition for 31 of 70 patients (44%), and add-on for 20 of 70 patients (29%). Efficacy profile of solriamfetol was the primary reason for de novo (12 of 19 [63%]), transition (18 of 31 [58%]), and add-on (19 of 20 [95%]) initiation. Most (86%) initiated use of solriamfetol at 75 mg/d and were stable at 150 mg/d (76%). Most (67%) had 1 dose adjustment, reaching a stable dose over a median (range) of 14 (1-60) days. Physicians most often considered EDS severity (44%) when titrating. Among transitioning patients, 14 of 22 (64%) using wake-promoting agents discontinued their use abruptly, and 5 of 9 (56%) using stimulants were tapered off. At data collection, 90% continued to take solriamfetol. Regarding the hypothetical patient scenario, most physicians (81%) thought solriamfetol was appropriate, highlighting tolerability issues with current treatment and lack of symptom control as drivers for switching; however, 3 physicians (12%) did not think solriamfetol was appropriate, noting current symptoms were not severe enough and/or symptoms could be managed by increasing sodium oxybate dose; 2 (8%) thought it would depend on other factors. Physicians emphasized managing withdrawal symptoms while maintaining EDS symptom control when titrating off a stimulant and starting solriamfetol therapy. IMPLICATIONS: In a real-world study, physicians initiated solriamfetol therapy at 75 mg/d for most patients with narcolepsy, adjusted dosages once, tapered stimulants, and abruptly discontinued therapy with wake-promoting agents.

Solriamfetol Titration and AdministRaTion (START) in Patients with Obstructive Sleep Apnea: A Retrospective Chart Review and Hypothetical Patient Scenario.

INTRODUCTION: Solriamfetol (Sunosi™), a dopamine/norepinephrine reuptake inhibitor, is approved (USA and EU) to treat excessive daytime sleepiness (EDS) in adults with obstructive sleep apnea (OSA) (37.5-150 mg/day). Real-world research on solriamfetol initiation is limited. The objective of this study was to describe dosing and titration strategies used when initiating solriamfetol and to assess whether and how patient factors affected these strategies. METHODS: This descriptive study, featuring a quantitative retrospective patient chart review and hypothetical patient scenario, enrolled US-based physicians prescribing solriamfetol for EDS associated with OSA and/or narcolepsy. Initiation of solriamfetol was classified as: (1) de novo (EDS medication-naive); (2) transition (switched/switching from existing EDS medication[s] to solriamfetol), or (3) add-on (adding solriamfetol to current EDS medication[s]). Study fielding occurred 3-19 June 2020. Data were summarized descriptively. RESULTS: Twenty-six physicians participated in the study, of whom 24 provided data from 50 patients with OSA (mean ± standard deviation [SD] age, 51.9 ± 9.1 years; 62% male). Mean apnea-hypopnea index at diagnosis indicated that most patients had severe OSA and 92% were adherent to positive airway pressure therapy. EDS was primarily moderate (56%) or severe (36%). Solriamfetol initiation was de novo for 44% of patients, transition for 52%, and add-on for 4%. Efficacy (including the need for better efficacy) was the primary reason for the initiation of solriamfetol as de novo (82%), transition (58%), and add-on (100%) therapy. Starting doses were predominantly 37.5 mg/day (48%) or 75 mg/day (48%); stable doses were typically 75 mg/day (56%) or 150 mg/day (40%). Most patients (64%) adjusted dosages once, reaching stable doses over a median (range) of 14 (1-74) days. Physicians considered EDS severity (32% of patients) when titrating, but more commonly no specific patient factors caused them to alter their titration (44% of patients). Physicians abruptly discontinued wake-promoting agents (WPAs; 17/18, 94%) and stimulants (6/9, 67%) for transitioning patients. The hypothetical patient scenario showed that physicians discontinuing prior WPAs commonly considered the current dose (23%) and potential adverse events (15%). Most patients (96%) were stable on solriamfetol at data collection. CONCLUSIONS: In a real-world study, most physicians initiated solriamfetol at 37.5 or 75 mg/day and titrated to 75 or 150 mg/day for patients with EDS associated with OSA, adjusted dosages once, and abruptly discontinued prior WPAs. At data collection, most patients remained on solriamfetol.

Noninvasive neuromodulation reduces symptoms of restless legs syndrome.

STUDY OBJECTIVES: Restless legs syndrome (RLS) is a common neurological disorder characterized by an uncontrollable nocturnal urge to move the legs and often associated with chronic sleep disturbances. The most common treatments for RLS are medications that can have debilitating side effects. Here, we evaluated a novel alternative modality of RLS treatment, noninvasive bilateral electrical stimulation of the common peroneal nerve. METHODS: To assess the impact of this noninvasive peripheral nerve stimulation (NPNS) approach to RLS symptomatology, we conducted a multisite randomized crossover study comparing NPNS to sham. RLS patients with moderate-to-severe RLS (n = 37) self-administered NPNS and sham nightly for 14 days per treatment in randomized order. RESULTS: NPNS resulted in a reduction in RLS severity of 6.81 points on the International RLS Rating Scale relative to 3.38 for sham (P < .01) and a 66% clinically significant responder rate on the Clinical Global Impressions-Improvement scale compared to 17% for sham (P < .01). Subgroup analysis indicated that medication-resistant and medication-naïve participants both exhibited similarly robust responses. There were no moderate or serious device-related adverse events. CONCLUSIONS: These results suggest that NPNS could be a promising alternative to pharmacological therapies for RLS and could provide a solution for medication-resistant RLS patients and for medication-naïve RLS patients who are unwilling or unable to take medication. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Noninvasive Peripheral Nerve Stimulation for Restless Legs Syndrome; URL: https://clinicaltrials.gov/ct2/show/NCT04700683; Identifier: NCT04700683. CITATION: Buchfuhrer MJ, Baker FC, Haramandeep S, et al. Noninvasive neuromodulation reduces symptoms of restless legs syndrome. J Clin Sleep Med. 2021;17(8):1685-1694.

Novel therapeutic usage of low-dose doxepin hydrochloride.

Low-dose doxepin hydrochloride (1, 3 and 6 mg) is a tricyclic antidepressant currently being investigated for the treatment of primary insomnia in adult and geriatric patients. Although it has been used at much higher doses to treat depression effectively for a number of decades, it offers a unique potency and selectivity for antagonizing the H1 (histamine) receptor at low doses. This mechanism of action may prove to be advantageous compared with other medications currently approved for the treatment of insomnia. This article reviews previous clinical studies using doxepin for insomnia and the recent clinical trial data, and briefly discusses other potential roles of this compound in clinical practice.