Current models of insomnia disorder: a theoretical review on the potential role of the orexinergic pathway with implications for insomnia treatment.

Insomnia disorder is considered as a stress-related disorder associated with hyperarousal, stress and emotion dysregulation and the instability of the 'flip-flop' switch system. The orexinergic system is well known for its key role in sleep and arousal processes but also in the allostatic system regulating stress and emotions and may thus be of major interest for insomnia and its treatment. Accordingly, we discuss the potential role of orexins on sleep processes, brain systems modulating stress and emotions with potential implications for insomnia pathophysiology. We reviewed available data on the effect of dual orexin receptor antagonists (DORAs) on sleep and brain systems modulating stress/emotions with implications for insomnia treatment. We present our findings as a narrative review. Few data in animals and humans have reported that disrupted sleep and insomnia may be related to the overactivation of orexinergic system, while some more consistent data in humans and animals reported the overactivation of orexins in response to acute stress and in stress-related disorders. Taken together these findings may let us hypothesise that an orexins overactivation may be associated with stress-related hyperarousal and the hyperactivation of arousal-promoting systems in insomnia. On the other hand, it is possible that by rebalancing orexins with DORAs we may regulate both sleep and allostatic systems, in turn, contributing to a 'switch off' of hyperarousal in insomnia. Nevertheless, more studies are needed to clarify the role of the orexin system in insomnia and to evaluate the effects of DORAs on sleep, stress and emotions regulating systems.

Hypnotics and injuries among older adults with Parkinson's disease: a nested case-control design.

BACKGROUND: Patients with Parkinson's disease often experience sleep disorders. Hypnotics increase the risk of adverse events, such as injuries due to falls. In this study, we evaluated the association between hypnotics and injuries among older adults with Parkinson's disease. METHODS: The study used a nested case-control design. The participants were 5009 patients with Parkinson's disease aged ≥ 75 years based on claims data between April 2016 and March 2019 without prescription hypnotics 1 year before the study started. Hypnotics prescribed as oral medications included benzodiazepines, non-benzodiazepines, orexin receptor antagonists, and melatonin receptor agonists. The incidences of outcomes, including injuries, fractures, and femoral fractures, were determined. Each case had four matched controls. Conditional logistic regression analyses were performed to calculate the odds ratios and 95% confidence intervals for the number of hypnotics taken per day for each type of hypnotic. RESULTS: The proportion of participants taking at least one type of hypnotic was 18.6%, with benzodiazepines being the most common. The incidence of injuries, fractures, and femoral fractures was 66.7%, 37.8%, and 10.2%, respectively. Benzodiazepines significantly increased the risk of injuries (odds ratio: 1.12; 95% confidence interval: 1.03-1.22), and melatonin receptor agonists significantly increased the risk of femoral fractures (odds ratio: 2.84; 95% confidence interval: 1.19-6.77). CONCLUSIONS: Benzodiazepines and non-benzodiazepines, which are not recommended according to current guidelines, were the most prevalent among older adults with Parkinson's disease. Benzodiazepines significantly increased the risk of injuries, and melatonin receptor agonists significantly increased the risk of femoral fractures.

Dual orexin receptor antagonists for insomnia in youth with neurodevelopmental disorders: a case series and review.

Insomnia is a common, impairing, and difficult-to-treat comorbidity in children with neurodevelopmental disorders (NDDs). Behavioral interventions can be challenging because of developmental and behavioral features that interfere with treatment. Medication management also can be difficult due to a high burden of side effects, a high rate of paradoxical responses, and frequent treatment resistance. Therefore, new treatment options for insomnia in children with NDDs are needed. Dual orexin receptor antagonists (DORAs) are a relatively new class of pharmacotherapeutics that induce sleep by inhibiting the orexin signaling pathway. To date, there is little safety or efficacy data on the use of DORAs in children with NDDs. We present four patients with NDDs and insomnia that we treated with the DORA, suvorexant. We found that patients had a wide range of responses, with one patient displaying a robust improvement in sleep onset and maintenance, while another had significant improvement in insomnia symptoms on combination therapy with trazodone. Our final two patients had mild or no benefit from suvorexant therapy. Further research is necessary to establish the safety and efficacy of DORAs in this population and to identify predictive factors, such as specific neurogenetic diagnoses or clinical features, of a positive treatment response.

Orexin Receptor Antagonists and Insomnia.

PURPOSE OF REVIEW: We review recent evidence on the use of orexin receptor antagonists (ORAs) for treating insomnia. We evaluate studies on five dual ORAs and one selective ORA. RECENT FINDINGS: Research on suvorexant in recent years gradually focus on comorbid insomnia, while lemborexant and daridorexant were still being validated in primary insomnia. Almorexant is now mainly used as a commercial specific inhibitor of the orexin system in animal studies due to safety issues. Although filorexant has also shown a certain sleep-promoting effect, there are few clinical or experimental studies on sleep-related aspects of filorexant in recent years. As for selective ORAs, orexin receptor 2 antagonist seltorexant still has not yet reached phase 3. High-quality clinical trials in insomnia populations are needed which directly compare authorized ORAs and investigate non-approved ORAs, the use of ORAs in comorbid insomnia, and the orexin signaling system pathophysiology in insomnia.

Daridorexant for the treatment of insomnia disorder: findings and implications.

PURPOSE: The involvement of the orexin system in the physiopathology of insomnia has been rapidly increasing in understanding. In this sense, daridorexant was the third orexin receptor antagonist approved by the FDA in January 2022. This review aims to summarize the chemistry, pharmacodynamics, pharmacokinetics, efficacy, safety, and tolerability profile of daridorexant for the treatment of insomnia disorder. METHODS: We performed a review of daridorexant for the treatment of insomnia disorder. The search was carried out in Medline via PubMed, Embase, and clinical trials, up to March 2022. RESULTS: Daridorexant 25 and 50 mg had more significant improvement for the wake after sleep onset (WASO), latency to persistent sleep (LPS), and subjective total sleep time (sTST) than placebo. In addition, daridorexant 50 mg was better for Insomnia Daytime Symptoms and Impacts Questionnaire (IDSIQ) than placebo. The most common adverse events were nasopharyngitis and headache. CONCLUSION: Daridorexant was efficacious and safe. Studies that evaluate the long-term safety and compare daridorexant with benzodiazepines, benzodiazepine receptor agonists, sedative antidepressants, and other orexin receptor antagonists are required.

The Discovery of Suvorexant, the First Orexin Receptor Drug for Insomnia.

Historically, pharmacological therapies have used mechanisms such as γ-aminobutyric acid A (GABAA) receptor potentiation to drive sleep through broad suppression of central nervous system activity. With the discovery of orexin signaling loss as the etiology underlying narcolepsy, a disorder associated with hypersomnolence, orexin antagonism emerged as an alternative approach to attenuate orexin-induced wakefulness more selectively. Dual orexin receptor antagonists (DORAs) block the activity of orexin 1 and 2 receptors to both reduce the threshold to transition into sleep and attenuate orexin-mediated arousal. Among DORAs evaluated clinically, suvorexant has pharmacokinetic properties engineered for a plasma half-life appropriate for rapid sleep onset and maintenance at low to moderate doses. Unlike GABAA receptor modulators, DORAs promote both non-rapid eye movement (NREM) and REM sleep, do not disrupt sleep stage-specific quantitative electroencephalogram spectral profiles, and allow somnolence indistinct from normal sleep. The preservation of cognitive performance and the ability to arouse to salient stimuli after DORA administration suggest further advantages over historical therapies.

Hypnotics with novel modes of action.

Insomnia and, more generally, lack of sleep are on the rise. Traditionally treated by classical hypnotics, such as benzodiazepines and Z drugs, which both act on the GABAA receptor, and other modalities, including nondrug therapies, such as cognitive behavioural therapy, there is a range of new hypnotics which are being developed or have recently received market approval. Suvorexant and the like target the orexin/hypocretin system: they should have less side effects in terms of drug-drug interactions with e.g. alcohol, less memory impairment and dependence potential compared to classical hypnotics.

Evidence for orexinergic mechanisms in migraine.

OBJECTIVE: To examine the effect of the orexinergic blockade with a dual orexin receptor antagonist (DORA) on experimental models of peripheral and central trigeminal as well as cortical activation relevant to migraine and migraine aura. METHODS: In this study we used a precursor of suvorexant, a dual orexin receptor antagonist #12 (DORA-12) in established experimental in vivo models of dural trigeminovascular nociception in rat. Neurogenic dural vasodilation and electrophysiological recordings of second order trigeminocervical neurons were used to study trigeminal nociceptive mechanisms directly. KCl-evoked cortical spreading depression was also used as a surrogate for migraine aura. RESULTS: Neurogenically-induced vasodilation of the middle meningeal artery, caused by nociceptive activation of peripheral afferent projections of the trigeminal nerve, was attenuated by intravenous DORA-12 (1 mgkg(-1)). Second-order trigeminocervical complex neuronal activity was significantly inhibited by intravenous DORA-12 (1 mgkg(-1)). DORA-12 significantly reduced susceptibility to KCl-evoked cortical spreading depression. CONCLUSION: The study provides the first direct evidence, that simultaneous antagonism on both orexin receptors is able to attenuate trigeminal nociceptive activity as well as to induce an elevation of the threshold for the induction of a cortical spreading depression (CSD). In the clinical context, these data imply that targeting the hypothalamic orexinergic system may offer an entirely novel mechanism for the preventive treatment of migraine with and without aura.

Substituted pyrrolidin-2-ones: Centrally acting orexin receptor antagonists promoting sleep. Part 2.

Starting from advanced pyrrolidin-2-one lead compounds, this novel series of small-molecule orexin receptor antagonists was further optimized by fine-tuning of the C-3 substitution at the γ-lactam ring. We discuss our design to align in vitro potency with metabolic stability and improved physicochemical/pharmacokinetic properties while avoiding P-glycoprotein-mediated efflux. These investigations led to the identification of the orally active 3-hydroxypyrrolidin-2-one 46, a potent and selective orexin-2 receptor antagonist, that achieved good brain exposure and promoted physiological sleep in rats.

Efficacy of Lemborexant in Adults ≥ 65 Years of Age with Insomnia Disorder.

BACKGROUND: Pharmacologic treatments are available to treat insomnia, a common and burdensome sleep disorder, but may be contraindicated in older adults who are prone to side effects from sleep-promoting drugs. These analyses of sleep diary data from Study E2006-G000-303 (Study 303) investigated the benefits of lemborexant 5 mg (LEM5) and 10 mg (LEM10) in the subgroup age ≥ 65 years with insomnia. METHOD: Study 303, a 12-month, double-blind study of LEM5 and LEM10 in adults (age ≥ 18 years) with insomnia disorder (sleep onset and/or maintenance difficulties) assessed subject-reported (subjective) sleep-onset latency (sSOL), sleep efficiency (sSE), wake after sleep onset (sWASO), and total sleep time (sTST). Morning sleepiness/alertness, insomnia severity (Insomnia Severity Index [ISI]), fatigue (Fatigue Severity Scale [FSS]), perceptions of sleep-related medication effects (Patient Global Impression-Insomnia [PGI-I] questionnaire), and safety were also evaluated. RESULTS: In this subgroup of older adults (≥ 65 years; n = 262), there were significantly larger changes from baseline for sSOL, sSE, sTST, and sWASO with LEM5 and LEM10 versus placebo through month 6 (except sWASO month 1), indicating improvement; these improvements were sustained through month 12. Subject-reported increases in morning alertness were significantly greater with one or both LEM doses versus placebo through month 6 and sustained through month 12. There were significantly larger ISI total and daytime functioning score decreases (improvement) from baseline with LEM versus placebo at months 1, 3, and 6 (total score: both doses; daytime functioning: LEM5 month 1 and both doses months 3 and 6) and decreases from baseline FSS at months 1 and 3 (LEM5) and month 6 (both doses), sustained to month 12. Compared with placebo, more subjects reported that LEM (both doses) positively impacted ability to sleep, time to fall asleep, and TST through month 6, sustained to month 12, with no rebound after drug withdrawal. LEM was well tolerated to month 12; mild somnolence was the most common treatment-emergent adverse event. CONCLUSIONS: Improvements in subject-reported efficacy in LEM-treated adults age ≥ 65 years with insomnia were observed as early as the first week of treatment and sustained through end of month 12. LEM was well tolerated. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov identifier NCT02952820: E2006-G000-303; Study 303; SUNRISE-2 (First posted: October 2016); EudraCT 2015-001463-39 (First posted: November 2016).

Insomnia is a common sleep disorder associated with significant difficulties, particularly in older adults. Although there are many drug treatments available, some are associated with the important risk of side effects and may not adequately treat sleep maintenance (ability to stay asleep), which is a frequent sleep complaint in older people. Lemborexant has been approved in multiple countries for the treatment of adults with insomnia based on studies that show lemborexant improved adults' ability to fall asleep and stay asleep and is well tolerated. To examine the long-term benefit of lemborexant, we investigated subject-reported benefits and safety of lemborexant in older (≥ 65 years) adults who participated in a 1-year study. The results showed that within the first few days of taking lemborexant, and lasting through 12 months of treatment, nightly lemborexant improved nighttime sleep (that is, it reduced the time it took to fall asleep, reduced the time awake during the night, and increased total sleep time) more than placebo. Morning alertness improved more in older adults who took lemborexant compared with placebo. In addition, those who took lemborexant also reported that their insomnia symptoms were less severe and they had less fatigue compared with placebo. Lemborexant was well tolerated in older adults. These results suggest that lemborexant may be a good option for older adults with insomnia disorder.

Association between dual orexin receptor antagonists (DORAs) and suicidality: reports to the United States Food and Drug Administration Adverse Event Reporting System (FAERS).

BACKGROUND: Package inserts for the FDA-approved dual orexin receptor antagonists (DORAs) suvorexant, lemborexant and daridorexant state that suicide risk should be monitored. It remains unknown whether suicidality is attributed to DORAs. We aim to evaluate suicidality associated with DORAs reported to the FDA Adverse Event Reporting System (FAERS). METHODS: The reporting odds ratio (ROR) was determined with trazodone as the control. Significant disproportionate reporting was determined when 95% confidence intervals (CIs) did not encompass 1.0. We used information components (ICs) to calculate the lower limit of the 95% CI (IC025). IC was significantly increased when the IC025 ≥0. RESULTS: Suvorexant (0.025 ROR), lemborexant (0.019 ROR) and daridorexant (0.002 ROR) were significantly associated with lower odds of reported completed suicides compared to trazodone (p < 0.05). There was no significantly increased RORs for the DORAs regarding suicidal ideation, depression suicidal, suicidal behavior and suicide attempts. Nonsignificant associations between all parameters of suicidality were observed for each DORA using IC025. CONCLUSION: We did not find a significant association between any parameter of suicidality captured in the FAERS for each DORA. All persons treated for insomnia pharmacologically/non-pharmacologically should be evaluated for emergence/worsening of any suicidality aspect.

Clinical safety and narcolepsy-like symptoms of dual orexin receptor antagonists in patients with insomnia: a systematic review and meta-analysis.

STUDY OBJECTIVES: Dual orexin receptor antagonists (DORAs) are emerging treatments for insomnia. This meta-analysis study aimed to assess the safety of FDA-approved DORAs (suvorexant, lemborexant, and daridorexant), focusing on narcolepsy-like symptoms associated with these drugs. METHODS: Five prominent databases were searched to identify randomized controlled trials (RCTs) on this topic. Primary safety outcomes included treatment-emergent adverse events (TEAEs), treatment-related TEAEs, TEAEs leading to discontinuation, and serious TEAEs. Excessive daytime sleepiness (EDS), sleep paralysis, and hallucinations were categorized as adverse events (AEs)-related narcolepsy-like symptoms. RESULTS: Eleven RCTs with 7703 patients were included. DORAs were associated with a higher risk of TEAEs (risk ratio [RR], 1.09; 95% confidence interval [CI], 1.03 to 1.15) and treatment-related TEAEs (RR, 1.69; 95% CI: 1.49 to 1.92) when compared to placebo. The DORA group exhibited a significantly higher risk of EDS (RR, 2.15; 95% CI: 1.02 to 4.52) and sleep paralysis (RR, 3.40; 95% CI: 1.18 to 9.80) compared to the placebo group. CONCLUSION: This meta-analysis achieved a comparative evaluation of the clinical safety and tolerability of FDA-approved DORAs for primary insomnia, specifically focusing on AEs-related narcolepsy-like symptoms. This study contributes to understanding the safety profile of FDA-approved DORAs for treating insomnia.

Clinical usefulness of dual orexin receptor antagonism beyond insomnia: Neurological and psychiatric comorbidities.

Orexin is a neurotransmitter produced by a small group of hypothalamic neurons. Besides its well-known role in the regulation of the sleep-wake cycle, the orexin system was shown to be relevant in several physiological functions including cognition, mood and emotion modulation, and energy homeostasis. Indeed, the implication of orexin neurotransmission in neurological and psychiatric diseases has been hypothesized via a direct effect exerted by the projections of orexin neurons to several brain areas, and via an indirect effect through orexin-mediated modulation of sleep and wake. Along with the growing evidence concerning the use of dual orexin receptor antagonists (DORAs) in the treatment of insomnia, studies assessing their efficacy in insomnia comorbid with psychiatric and neurological diseases have been set in order to investigate the potential impact of DORAs on both sleep-related symptoms and disease-specific manifestations. This narrative review aimed at summarizing the current evidence on the use of DORAs in neurological and psychiatric conditions comorbid with insomnia, also discussing the possible implication of modulating the orexin system for improving the burden of symptoms and the pathological mechanisms of these disorders. Target searches were performed on PubMed/MEDLINE and Scopus databases and ongoing studies registered on Clinicaltrials.gov were reviewed. Despite some contradictory findings, preclinical studies seemingly support the possible beneficial role of orexin antagonism in the management of the most common neurological and psychiatric diseases with sleep-related comorbidities. However, clinical research is still limited and further studies are needed for corroborating these promising preliminary results.

Emerging and upcoming therapies in insomnia.

Insomnia, commonly treated with benzodiazepine (BZD) receptor agonists, presents challenges due to associated serious side effects such as abuse and dependence. To address these concerns, many researches have been conducted to develop and advance both pharmacological and non-pharmacological interventions. Dual orexin receptor antagonists (DORAs), which include suvorexant, daridorexant and lemborexant, have recently been approved by United States Food and Drug Administration (US FDA) as a novel pharmacotherapeutic alternative. Unlike BZD receptor agonists that act as positive allosteric modulators of the gamma-aminobutyric acid type A subunit alpha 1 receptor, DORAs function by binding to both orexin receptor types 1 and 2, and inhibiting the action of the wake-promoting orexin neuropeptide. These drugs induce normal sleep without sleep stage change, do not impair attention and memory performance, and facilitate easier awakening. However, more real-world safety information is needed. Selective orexin-2 receptor antagonists (2-SORAs) is under clinical developments. This review provides an overview of the mechanism of action in relation to insomnia, pharmacokinetics, efficacy and safety information of DORAs and SORA. According to insomnia management guidelines, the first-line treatment for chronic insomnia is cognitive behavioral therapy for insomnia (CBT-I). Although it has proven effective in improving sleep-related quality of life, it has several restrictions limitations due to a face-to-face format. Recently, prescription digital therapy such as Somryst® was approved by US FDA. Somryst®, a smartphone app-based CBT-I, demonstrated meaningful responses in patients. However, digital limitations may impact scalability. Overall, these developments offer promising alternatives for insomnia treatment, emphasizing safety, efficacy, and accessibility.

Data mining and safety analysis of dual orexin receptor antagonists (DORAs): a real-world pharmacovigilance study based on the FAERS database.

Objective: Using the Food and Drug Administration Adverse Event Reporting System (FAERS) database, four signal detection methods were applied to mine adverse drug events (ADEs) related to use of dual orexin receptor antagonists (DORAs) to provide reference for safe clinical use. Research design and Methods: Data collected from Q3rd 2014 to Q4th 2023 were obtained from the FAERS database. According to the preferred terminology (PT) and systematic organ classification (SOC) of MedDRA v.26.0, the reporting odds ratio (ROR), proportional reporting ratio (PRR), multi-item gamma Poisson shrinker (MGPS), and Bayesian confidence propagation neural network (BCPNN) were used to detect ADE signals. Results: A total of 11,857 DORAs-related adverse reactions were detected, reported with suvorexant, lemborexant, and daridorexant as the main suspected drugs was 8717584, and 2556, respectively. A higher proportion of females than males were reported (57.27% vs. 33.04%). The top 20 positive PT signals from three DORAs showed that "sleep paralysis" ranked first. "Brain fog" was stronger following daridorexant but was not detected for the other two drugs, and "sleep sex" and "dyssomnia" were stronger in suvorexant but not in the other two drugs. Additionally, some PTs occurred that were not included in drug instructions, such as "hangover" and "hypnagogic hallucination." Conclusion: In this study, four algorithms (ROR, PRR, BCPNN, and MGPS) were used to mine the safety signals of DORAs. We identified some potential ADE signals that can promote the rational use of DORAs and improve their safety.

Lemborexant-induced interstitial lung disease: A case report.

We report the first case of drug-induced interstitial lung disease attributed to lemborexant. A 66-year-old man reported to our hospital with the acute onset of cough and breathlessness with ground-glass opacity on radiological examination. Symptoms were identified after taking lemborexant for 2 consecutive days. The patient had undergone lemborexant treatment 2 years prior and had exhibited no symptoms at that time. The drug-induced lymphocyte stimulation test for lemborexant was positive. He showed rapid improvement upon treatment with steroid. With the rise in prescriptions of lemborexant for insomnia, lemborexant should be considered as a possible cause of drug-induced interstitial lung disease.

Discovery of 2,5-diarylnicotinamides as selective orexin-2 receptor antagonists (2-SORAs).

The orexin (or hypocretin) system has been identified as a novel target for the treatment of insomnia due to the wealth of biological and genetic data discovered over the past decade. Recently, clinical proof-of-concept was achieved for the treatment of primary insomnia using dual (OX1R/OX2R) orexin receptor antagonists. However, elucidation of the pharmacology associated with selective orexin-2 receptor antagonists (2-SORAs) has been hampered by the lack of orally bioavailable, highly selective small molecule probes. Herein, the discovery and optimization of a novel series of 2,5-diarylnicotinamides as potent and orally bioavailable orexin-2 receptor selective antagonists is described. A compound from this series demonstrated potent sleep promotion when dosed orally to EEG telemetrized rats.

Targeting Orexin Receptors for the Treatment of Insomnia: From Physiological Mechanisms to Current Clinical Evidence and Recommendations.

After a detailed description of orexins and their roles in sleep and other medical disorders, we discuss here the current clinical evidence on the effects of dual (DORAs) or selective (SORAs) orexin receptor antagonists on insomnia with the aim to provide recommendations for their further assessment in a context of personalized and precision medicine. In the last decade, many trials have been conducted with orexin receptor antagonists, which represent an innovative and valid therapeutic option based on the multiple mechanisms of action of orexins on different biological circuits, both centrally and peripherally, and their role in a wide range of medical conditions which are often associated with insomnia. A very interesting aspect of this new category of drugs is that they have limited abuse liability and their discontinuation does not seem associated with significant rebound effects. Further studies on the efficacy of DORAs are required, especially on children and adolescents and in particular conditions, such as menopause. Which DORA is most suitable for each patient, based on comorbidities and/or concomitant treatments, should be the focus of further careful research. On the contrary, studies on SORAs, some of which seem to be appropriate also in insomnia in patients with psychiatric diseases, are still at an early stage and, therefore, do not allow to draw definite conclusions.

Switching to lemborexant for the management of insomnia in mental disorders: the SLIM study.

STUDY OBJECTIVES: We conducted a retrospective study to investigate the efficacy and safety of switching from other hypnotics, including benzodiazepines and Z-drugs, suvorexant, ramelteon, mirtazapine, trazodone, and antipsychotics, to lemborexant, a dual orexin receptor antagonist, for 3 months. METHODS: Clinical data obtained from the medical records of 61 patients treated at the Horikoshi Psychosomatic Clinic between December 2020 and February 2022 were analyzed, including the Athens Insomnia Scale, Epworth Sleepiness Scale, and Perceived Deficits Questionnaire-5. The primary outcome was the mean change in Athens Insomnia Scale score after 3 months. Secondary outcomes were the mean changes in the Epworth Sleepiness Scale and Perceived Deficits Questionnaire-5 scores over 3 months. We also compared pre- and post-diazepam equivalents. RESULTS: The mean Athens Insomnia Scale score decreased over 3 months after switching to lemborexant (1 mo: -2.98 ± 5.19, P < .001; 2 mo: -3.20 ± 5.64, P < .001; 3 mo: -3.38 ± 5.61, P < .001). Mean Epworth Sleepiness Scale score did not change from baseline to 1 month (-0.49 ± 3.41, P = 0.27), 2 months (0.082 ± 4.62, P = .89), or 3 months (-0.64 ± 4.80, P = .30). Mean Perceived Deficits Questionnaire-5 score did improve from baseline to 1 month (-1.17 ± 2.47, P = .004), 2 months (-1.05 ± 2.97, P = .029), and 3 months (-1.24 ± 3.06, P = .013). There was also a reduction in the total diazepam equivalent (baseline vs 3 mo: 14.0 ± 20.2 vs 11.3 ± 20.6, P < .001). CONCLUSIONS: Our study showed that, by switching to lemborexant from other hypnotics, the risks associated with benzodiazepines and Z-drugs may be reduced. CITATION: Horikoshi S, Miura I, Suzuki Y, et al. Switching to lemborexant for the management of insomnia in mental disorders: the SLIM study. J Clin Sleep Med. 2023;19(10):1753-1758.

Suvorexant, an FDA-approved dual orexin receptor antagonist, reduces oxycodone self-administration and conditioned reinstatement in male and female rats.

Background: The Department of Health and Human Services reports that prescription pain reliever (e.g., oxycodone) misuse was initiated by 4,400 Americans each day in 2019. Amid the opioid crisis, effective strategies to prevent and treat prescription opioid use disorder (OUD) are pressing. In preclinical models, the orexin system is recruited by drugs of abuse, and blockade of orexin receptors (OX receptors) prevents drug-seeking behavior. The present study sought to determine whether repurposing suvorexant (SUV), a dual OX receptor antagonist marketed for the treatment of insomnia, can treat two features of prescription OUD: exaggerated consumption and relapse. Methods: Male and female Wistar rats were trained to self-administer oxycodone (0.15 mg/kg, i. v., 8 h/day) in the presence of a contextual/discriminative stimulus (SD) and the ability of SUV (0-20 mg/kg, p. o.) to decrease oxycodone self-administration was tested. After self-administration testing, the rats underwent extinction training, after which we tested the ability of SUV (0 and 20 mg/kg, p. o.) to prevent reinstatement of oxycodone seeking elicited by the SD. Results: The rats acquired oxycodone self-administration and intake was correlated with the signs of physical opioid withdrawal. Additionally, females self-administered approximately twice as much oxycodone as males. Although SUV had no overall effect on oxycodone self-administration, scrutiny of the 8-h time-course revealed that 20 mg/kg SUV decreased oxycodone self-administration during the first hour in males and females. The oxycodone SD elicited strong reinstatement of oxycodone-seeking behavior that was significantly more robust in females. Suvorexant blocked oxycodone seeking in males and reduced it in females. Conclusions: These results support the targeting of OX receptors for the treatment for prescription OUD and repurposing SUV as pharmacotherapy for OUD.