Orexin Receptor Research Articles

ORX750, an oral selective Orexin Receptor 2 agonist, promotes wakefulness and reduces cataplexy in the orexin/ataxin-3 mouse

ORX750, an oral selective Orexin Receptor 2 agonist, promotes wakefulness and reduces cataplexy in the orexin/ataxin-3 mouse

The effect of dual orexin receptor antagonists on next-day driving: a systematic review and meta-analysis

The effect of dual orexin receptor antagonists on next-day driving: a systematic review and meta-analysis

Daridorexant treatment for chronic insomnia: a real-world retrospective single-center study

IntroductionChronic insomnia disorder (CID) significantly impacts well-being and daily functioning. Daridorexant, a double orexin receptor blocker, has shown efficacy in randomized clinical trials and has been recently approved for the treatment of CID in adult patients. This retrospective observational study aimed to describe real-world data on daridorexant effectiveness and safety in adult patients with CID.MethodsConsecutive patients initiating on-label daridorexant at the Sleep Medicine Centre, University Hospital of Rome Tor Vergata were enrolled. Baseline and 30-day follow-up (FU) evaluations included patients’ and CID characteristics, comorbidities, and clinicians’ and patients’ subjective ratings of changes with the Clinical and Patient Global Impression-Improvement scores (CGI-Is and PGI-Is), as well as Insomnia Severity Index (ISI) scores in a subgroup of patients.ResultsSixty-nine patients initiated 50-mg daily dosage. At FU, 58% of both patients and clinicians rated CID as improved on CGI-Is and PGI-Is, with no differences based on comorbidities, sex, or number of previous medications. No significant predictors of CGI-Is and PGI-Is improvement were identified. At FU, ISI scores (n = 24) significantly decreased from 18.25 ± 3.21 to 12.08 ± 6.12 (Z = 8.000; p < 0.001). Of these, eight patients (33.3%) had absence of insomnia symptoms, and no patients reported a worsening in ISI score categories.ConclusionsThis study suggests daridorexant to be effective and safe in real-world CID treatment whether used as a first-ever treatment, switch, or add-on, as reflected by subjective and objective measures and the absence of serious treatment-related adverse events. Future research on larger cohorts should explore daridorexant potential across diverse patient characteristics.

Insomnia Guidelines—The European Update 2023

The last ten years have seen the development and publication of numerous national and international guidelines devoted to the diagnosis and treatment of insomnia. These include guidelines by the American College of Physicians (ACP), the American Academy of Sleep Medicine (AASM), the British Sleep Society (BSS), the German Sleep Society (GSS), and the European Sleep Research Society (ESRS). Though coming from very diverse authors and backgrounds, these guidelines by and large agree concerning the therapeutic recommendations: cognitive behavioral treatment of insomnia (CBT-I), a multicomponent psychotherapeutic intervention, is unequivocally recommended as a first-line treatment. In this report, we will focus on the most recent guideline update from the ESRS, which was published in November 2023. After suggesting a careful diagnostic procedure, CBT-I, both applied face to face (F2F) or digitally (dCBT-I), is again recommended as a first-line treatment based on the available evidence. Hypnotic medications like benzodiazepines (BZ), benzodiazepine receptor agonists (BZRA), sedating antidepressants, and others are approved for short-term-treatment of up to four weeks. Orexin receptor antagonists (i.e., daridorexant) and prolonged release melatonin are considered as options for longer-term treatment when carefully considering the advantages and disadvantages. Both light therapy and exercise regimens were viewed as promising; however, they still lack convincing evidence for the time being. Given the fact that not every patient responds satisfactorily or even remits following CBT-I or other treatment options, the research agenda calls for the development and evaluation of new therapeutic avenues and combination therapies.

Orexin-A attenuated motion sickness through modulating neural activity in hypothalamus nuclei.

We evaluated the hypothesis that central orexin application could counteract motion sickness responses through regulating neural activity in target brain areas. Thec effects of intracerebroventricular (i.c.v.) injection of orexin-A and SB-334867 (OX1 antagonist) on motion sickness-induced anorexia, nausea-like behaviour (conditioned gaping), hypoactivity and hypothermia were investigated in rats subjected to Ferris wheel-like rotation. Orexin-A responsive brain areas were identified using Fos immunolabelling and were verified via motion sickness responses after intranucleus injection of orexin-A, SB-334867 and TCS-OX2-29 (OX2 antagonist). The efficacy of intranasal application of orexin-A versus scopolamine on motion sickness symptoms in cats was also investigated. Orexin-A (i.c.v.) dose-dependently attenuated motion sickness-related behavioural responses and hypothermia. Fos expression was inhibited in the ventral part of the dorsomedial hypothalamus (DMV) and the paraventricular nucleus (PVN), but was enhanced in the ventral part of the premammillary nucleus ventral part (PMV) by orexin-A (20 μg) in rotated animals. Motion sickness responses were differentially inhibited by orexin-A injection into the DMV (anorexia and hypoactivity), the PVN (conditioned gaping) and the PMV (hypothermia). SB-334867 and TCS-OX2-29 (i.c.v. and intranucleus injection) inhibited behavioural and thermal effects of orexin-A. Orexin-A (60 μg·kg-1) and scopolamine inhibited rotation-induced emesis and non-retching/vomiting symptoms, while orexin-A also attenuated anorexia with mild salivation in motion sickness cats. Orexin-A might relieve motion sickness through acting on OX1 and OX2 receptors in various hypothalamus nuclei. Intranasal orexin-A could be a potential strategy against motion sickness.

Novel orexin receptor agonists based on arene- or pyridine-fused 1,3-dihydro-2H-imidazole-2-imines

A structurally novel class of benzo- or pyrido-fused 1,3-dihydro-2H-imidazole-2-imines was designed and evaluated in an inositol phosphate accumulation assay for Gq signaling to measure agonistic activation of the orexin receptor type 2 (OX2R). These compounds were synthesized in 4–9 steps overall from readily available starting materials. Analogs that contain a stereogenic methyl or cyclopropyl substituent at the benzylic center, and a correctly configured alkyl ether, alkoxyalkyl ether, cyanoalkyl ether, or α-hydroxyacetamido substituted homobenzylic sidechain were identified as the most potent activators of OX2R coupled Gq signaling. Our results also indicate that agonistic activity was stereospecific at both the benzylic and homobenzylic stereogenic centra. We identified methoxyethoxy-substituted pyrido-fused dihydroimidazolimine analog 63c containing a stereogenic benzylic methyl group was the most potent agonist, registering a respectable EC50 of 339 nM and a maximal response (Emax) of 96 % in this assay. In vivo pharmacokinetic analysis indicated good brain exposure for several analogs. Our combined results provide important information towards a structurally novel class of orexin receptor agonists distinct from current chemotypes.

The effect of lemborexant on insomnia in patients with psychiatric disorders: Detailed evaluation using the Athens Insomnia Scale.

Chronic insomnia disorder is common and associated with reduced quality of life. Benzodiazepine hypnotics are commonly prescribed for insomnia, but have potential side effects such as concentration impairment, somnolence, and dependence. Lemborexant (LEM) is an orexin receptor antagonist considered to have fewer side effects than benzodiazepine hypnotics. This study evaluated the effect of LEM on sleep in detail and examined whether benzodiazepine hypnotics can be gradually tapered by adding LEM. We retrospectively examined the effectiveness of LEM in 28 outpatients with insomnia. Insomnia symptoms were assessed using the Athens Insomnia Scale (AIS) before and after LEM administration. We also attempted to taper benzodiazepine hypnotics and assessed benzodiazepine dose using diazepam equivalents for some patients taking benzodiazepine hypnotics. Wilcoxon's signed-rank test was used for statistical analysis. The mean AIS score was significantly improved after LEM treatment (8.7 ± 5.2 vs. 3.8 ± 3.3; P < 0.01). Among the AIS subitems, significant improvement was observed for six items: sleep induction, awakenings during the night, sleep quality, well-being, functioning capacity, and sleepiness during the day. The mean benzodiazepine dose was significantly lower after LEM treatment (4.6 ± 5.0 mg vs. 2.1 ± 3.3 mg; P < 0.01). This study indicated the potential of LEM for improving insomnia and reducing benzodiazepine dose.

Whole Brain Mapping of Orexin Receptor mRNA Expression Visualized by Branched In Situ Hybridization Chain Reaction.

Orexins, which are produced within neurons of the lateral hypothalamic area, play a pivotal role in the regulation of various behaviors, including sleep/wakefulness, reward behavior, and energy metabolism, via orexin receptor type 1 (OX1R) and type 2 (OX2R). Despite the advanced understanding of orexinergic regulation of behavior at the circuit level, the precise distribution of orexin receptors in the brain remains unknown. Here, we develop a new branched in situ hybridization chain reaction (bHCR) technique to visualize multiple target mRNAs in a semiquantitative manner, combined with immunohistochemistry, which provided comprehensive distribution of orexin receptor mRNA and neuron subtypes expressing orexin receptors in mouse brains. Only a limited number of cells expressing both Ox1r and Ox2r were observed in specific brain regions, such as the dorsal raphe nucleus and ventromedial hypothalamic nucleus. In many brain regions, Ox1r-expressing cells and Ox2r-expressing cells belong to different cell types, such as glutamatergic and GABAergic neurons. Moreover, our findings demonstrated considerable heterogeneity in Ox1r- or Ox2r-expressing populations of serotonergic, dopaminergic, noradrenergic, cholinergic, and histaminergic neurons. The majority of orexin neurons did not express orexin receptors. This study provides valuable insights into the mechanism underlying the physiological and behavioral regulation mediated by the orexin system, as well as the development of therapeutic agents targeting orexin receptors.

Interaction modes of human orexin 2 receptor with selective and nonselective antagonists studied by NMR spectroscopy

Orexin neuropeptides have many physiological roles in the sleep-wake cycle, feeding behavior, reward demands, and stress responses by activating cognitive receptors, the orexin receptors (OX1R and OX2R), distributed in the brain. There are only subtle differences between OX1R and OX2R in the orthosteric site, which has hindered the rational development of subtype-selective antagonists. In this study, we utilized solution-state NMR to capture the structural plasticity of OX2R labeled with 13CH3-ε-methionine in complex with antagonists. Mutations in the orthosteric site allosterically affected the intracellular tip of TM6. Ligand exchange experiments with the subtype-selective EMPA and the nonselective suvorexant identified three methionine residues that were substantially perturbed. The NMR spectra suggested that the suvorexant-bound state exhibited more structural plasticity than the EMPA-bound state, which has not been foreseen from the close similarity of their crystal structures, providing insights into dynamic features to be considered in understanding the ligand recognition mode.

Orexin and cannabinoid systems modulate long-term potentiation of the hippocampus CA1 area in anesthetized rats.

Long-term potentiation (LTP) is a kind of synaptic plasticity and has a key role in learning and memory. Endocannabinoids and orexins are the endogenous systems that can modulate synaptic plasticity. Given that new studies have shown an interaction between cannabinoid and orexin systems in the brain, we decided to examine this interaction between the two systems on LTP induction in rat's hippocampus. Twenty-eight male Wistar rats were used for evaluating the effects of co-administrating of cannabinoid-1 receptor (CB1R) antagonist (AM251) and orexin-2 receptor (OX2R) antagonist (TCS OX2 29) on the induction of LTP in the Schaffer collateral-CA1 synapses of rat hippocampus. The drugs were microinjected into the CA1 area of rat hippocampus 30 min before inducing of LTP. Results showed that sole administration of the antagonists inhibited LTP, with respect to the control group. Also, co-administrating of them reduced LTP as compared to the control group, but not significantly more than that when the antagonists were solely microinjected into the CA1. Nonetheless, the inhibitory effect of concurrent administration of the antagonists on LTP lasted until the end of the recording. These results propose that endogenous cannabinoids and orexins play a role in the expression of LTP, at least by CA1-CB1Rs and CA1-OX2Rs, respectively. Finally, there is no interaction between CB1R and OX2R on the induction of LTP in the Schaffer collateral-CA1 synapses; therefore, these two systems possibly act through common signaling pathways in the hippocampus's CA1 region.

A novel, non-opioid, selective orexin-1 receptor antagonist for the treatment of substance use disorders

There is a pressing need for novel treatments for substance use disorders to address increasing rates of addiction and drug overdose. Preclinical studies have shown that the orexin (hypocretin) system in the brain, mediated primarily by the orexin 1 receptor, plays a role in reward-related behaviours and that selective blockade of this receptor is efficacious in rodent models of addiction for a wide range of substances including opioids, cocaine, nicotine, and alcohol. We report here the preclinical profile of C4X3256, a novel, selective oral antagonist of the orexin 1 receptor. In the rat, high levels of receptor occupancy were observed in the tenia tecta region of the brain for up to 8 h following oral dosing. Translation of brain receptor occupancy into pharmacological efficacy was demonstrated in rat models showing significantly reduced nicotine self-administration and diminished cue-induced reinstatement of nicotine seeking following an oral dose of 30 mg/kg C4X3256. In addition, C4X3256 significantly reduced reinstatement of cocaine seeking induced by presentation of tone/light cues in a rat model of relapse. In summary, the nonclinical profile of C4X3256 has supported the progression of this compound into human clinical trials as an investigational medicinal product for the treatment of substance use disorders.

Improvement of autistic-like behaviors in adult rats prenatally exposed to valproic acid through early suppression of orexin receptor.

Autism spectrum disorder (ASD) is a disabling psychiatric disease characterized by impairments in communication and social skills. The pathophysiology of autism is complex and not fully known. Considering the incidence of sleep disorders in individuals with ASD and the important role of orexin in sleep, it is possible to hypothesize that an alteration of the orexinergic system could be implicated in the pathogenesis of autism symptoms. The present study was conducted to investigate the effect of suvorexant [dual orexin receptor antagonists (DORAs)] on autism-like behavior in prenatally valproic acid (VPA)-exposed rats]. Wistar female rats were administered VPA [600 mg/kg, intraperitoneally (i.p.)] or normal saline (10 ml/kg, i.p.; vehicle control) on gestational day 12.5. Thirty-two male offspring were divided into four groups: Control, VPA, Suvorexant+VPA, and VPA+Risperidone. The pups were given suvorexant [20 ml/kg, by mouth/orally (p.o.)] or risperidone (1 ml/kg, p.o.) daily from postnatal day (PND) (40-54). The offspring were tested for repetitive behaviors and cognitive ability with a Y-maze task on PND 55, and social interaction was assessed by play behavior in the open field on PND 56. And anxiety with using the three-chamber social assay on PND 56. In the Y-maze apparatus, spontaneous alteration significantly decreased in the prenatal VPA-treated rats compared to control rats showing autistic-like behavior, and 2-week suvorexant increased the alternation, indicating the beneficial effect of suvorexant. Prenatal treatment with VPA, impaired play behavior (sniffing, grooming, and darting), and increased anxiety-related behavior. Suvorexant treatment attenuated the problems in male offspring's social behavior. Our results showed that suvorexant improved ASD-associated behaviors in the VPA-treated rats, and the orexinergic system may be associated with the pathogenesis of autism symptoms.

Effects of swimming training on orexin receptor 2 distribution in brain damage of rats

Effects of swimming training on orexin receptor 2 distribution in brain damage of rats

A comprehensive review of the use of lemborexant in treating insomnia

Abstract Lemborexant (LEM), a dual orexin receptor antagonist, represents a significant advancement in treating insomnia, a prevalent sleep disorder affecting a considerable portion of the population, especially older adults in India. LEM has several benefits over conventional sedatives in the treatment of insomnia, such as the selective mechanism of action, lower risk of tolerance and dependence, better sleep architecture, reduced possibility of cognitive impairment, various dosing options, the risk of rebound insomnia, and the risk of drug–drug interactions are also decreased. This thorough examination explores the pharmacological mechanisms, pharmacokinetics, clinical effectiveness, and safety profile of LEM, providing valuable insights into its distinct mode of action compared with traditional medications targeting gamma-aminobutyric acid receptors. By blocking orexin receptors (orexin 1 receptor and orexin 2 receptor), LEM regulates neuropeptides orexin A and orexin B, crucial for controlling wakefulness and arousal. Clinical trials demonstrate its predictable pharmacokinetics, dose-dependent effects, and minimal adverse reactions, confirming its efficacy in improving sleep initiation and maintenance. Long-term studies on LEM’s sustained therapeutic benefits show no signs of rebound insomnia or withdrawal. Its favorable safety profile, including minimal impact on next-day functioning, cognitive abilities, and postural stability, sets it apart from other treatments. The exploration of potential drug interactions underscores the importance of cautious prescribing, especially concerning cytochrome P450 3A inhibitors and inducers. As LEM becomes integrated into healthcare protocols, it promises to be a well-tolerated and effective solution, reshaping standard treatment approaches for insomnia and overcoming the limitations of older medications. In summary, LEM is a valuable addition to the pharmacotherapeutic toolbox, offering a novel strategy for managing sleep disturbances with sustained efficacy and favorable safety features.

Endogenous orexin and hyperacute autonomic responses after resuscitation in a preclinical model of cardiac arrest.

The study of autonomic responses to cardiac arrest (CA) resuscitation deserves attention due to the impact of autonomic function on survival and arousal. Orexins are known to modulate autonomic function, but the role of endogenous orexin in hyperacute recovery of autonomic function post-resuscitation is not well understood. We hypothesized that endogenous orexin facilitates hyperacute cardiovascular sympathetic activity post-resuscitation, and this response could be attenuated by suvorexant, a dual orexin receptor antagonist. A well-established 7-min asphyxial CA rat model was studied. Heart rate (HR) and blood pressure were monitored from baseline to 90-min post-resuscitation. Autonomic function was evaluated by spectral analysis of HR variability, whereby the ratio of low- and high-frequency components (LF/HF ratio) represents the balance between sympathetic/parasympathetic activities. Plasma orexin-A levels and orexin receptors immunoreactivity in the rostral ventrolateral medulla (RVLM), the key central region for regulating sympathetic output, were measured post-resuscitation. Neurological outcome was assessed via neurologic-deficit score at 4-h post-resuscitation. A significant increase in HR was found over 25-40 min post-resuscitation (p < 0.01 vs. baseline), which was attenuated by suvorexant significantly (p < 0.05). Increased HR (from 15-to 25-min post-resuscitation) was correlated with better neurological outcomes (rs = 0.827, p = 0.005). There was no evident increase in mean arterial pressure over 25-40 min post-resuscitation, while systolic pressure was reduced greatly by suvorexant (p < 0.05). The LF/HF ratio was higher in animals with favorable outcomes than in animals injected with suvorexant over 30-40 min post-resuscitation (p < 0.05). Plasma orexin-A levels elevated at 15-min and peaked at 30-min post-resuscitation (p < 0.01 vs. baseline). Activated orexin receptors-immunoreactive neurons were found co-stained with tyrosine hydroxylase-immunopositive cells in the RVLM at 2-h post-resuscitation. Together, increased HR and elevated LF/HF ratio indicative of sympathetic arousal during a critical window (25-40 min) post-resuscitation are observed in animals with favorable outcomes. The orexin system appears to facilitate this hyperacute autonomic response post-CA.

Activation of orexin-A (hypocretin-1) receptors in the Raphe Pallidus at different ambient temperatures in the rat: effects on thermoregulation, cardiovascular control, sleep, and feeding behavior.

The Raphe Pallidus (RPa) is a brainstem nucleus containing sympathetic premotor neurons that control thermogenesis and modulate cardiovascular function. It receives inputs from various hypothalamic areas, including the Lateral Hypothalamus (LH), a heterogeneous region intricately involved in several autonomic and behavioral functions. A key subpopulation of neurons in the LH expresses orexin/hypocretin, a neuropeptide which is crucially involved in the regulation of the wake-sleep states and feeding behavior. The RPa receives orexinergic projections from the LH and orexinergic signalling in the RPa has been shown to enhance thermogenesis in the anaesthetized rat, but only in the presence of an already existing thermogenic drive, without significantly affecting cardiovascular function. The present work was aimed at exploring the effects on thermoregulation and autonomic function and the possible role in the modulation of the wake-sleep states and feeding behavior of orexin injection in the RPa in the free-behaving rat. In order to assess the influence of an already present thermogenic drive on orexinergic signalling in the RPa, animals were studied at three different ambient temperatures (Ta, 10°C, 24°C, and 32°C). We found that orexin injection into the RPa variably affected the wake-sleep states, autonomic functions, motor activity, and feeding behavior, at the different Tas. In particular, in the first post-injection hour, we observed an increase in wakefulness, which was large at Ta 24°C and Ta 10°C and rather mild at Ta 32°C. Deep brain temperature was increased by orexin injection at Ta 10°C, but not at either Ta 24°C or Ta 32°C. Moreover, an increase in mean arterial blood pressure occurred at Ta 24°C, which was probably masked by the high baseline levels at Ta 10°C and was completely absent at Ta 32°C. Finally, an enhancement in feeding behavior was observed at Ta 24°C and 10°C only. In accordance with what observed in anaesthetized rats, orexinergic signalling in the RPa seems to be ineffective in the absence of any thermogenic drive. Moreover, the effects observed on the wake-sleep states and feeding behavior introduce the RPa as a novel player in the central neural network promoting wakefulness and feeding.

Pyrazole derivatives as selective orexin-2 receptor antagonists (2-SORA): synthesis, structure-activity-relationship, and sleep-promoting properties in rats.

Selective orexin 2 receptor antagonists (2-SORA) such as seltorexant (15) are in clinical development for the treatment of insomnia and other conditions such as depression. Herein, we report our structure-activity-relationship (SAR) optimization efforts starting from an HTS hit (1) (N-(1-((5-acetylfuran-2-yl)methyl)-1H-pyrazol-4-yl)-5-(m-tolyl)oxazole-4-carboxamide) that was derived from an unrelated in-house GPCR-agonist program. Medicinal chemistry efforts focused on the optimization of orexin 2 receptor (OX2R) antagonistic activity, stability in liver microsomes, time dependent CYP3A4 inhibition, and aqueous solubility. Compounds were assessed for their brain-penetrating potential in in vivo experiments to select the most promising compounds for our in vivo sleep model. Our lead optimization efforts led to the discovery of the potent, brain penetrating and orally active, 2-SORA (N-(1-(2-(5-methoxy-1H-pyrrolo[3,2-b]pyridin-3-yl)ethyl)-1H-pyrazol-4-yl)-5-(m-tolyl)oxazole-4-carboxamide) 43 with efficacy in a sleep model in rats comparable to 15.

Anxiolytic-like effects of the dual orexin receptor antagonist daridorexant in rats

Dual orexin receptor antagonists (DORAs) belong to a novel class of sleep medications that function by blocking the actions of wakefulness-promoting orexin neuropeptides in sleep-wake centers of the brain. Orexins also transmit signals to brain nuclei that regulate emotions and stress responses. The effects of DORAs on anxiety-like reactions requires further exploration. The hyperarousal theory of insomnia suggests an underlying overactivation of the body's stress response systems, and a considerable proportion of insomnia patients suffers from concurrent anxiety disorders. Hence, it is important for physicians to be certain that novel insomnia treatments do not exacerbate, but rather alleviate, patients' anxiety and psychological stress responses. Our aim was to test the effect of the new DORA daridorexant on diverse anxiety- and fear-evoked behavioral and physiological reactions in rats to gain first insight into the drug's potential in humans. Daridorexant, given orally at 10, 30 and 100 mg/kg 1 h before testing, resulted in a dose-dependent reduction of fear-potentiated acoustic startle (FPS) reactions, schedule-induced polydipsia (SIP) and social stress-induced hyperthermia and tachycardia (SIH/T). Furthermore, under non-stressful, basal conditions, daridorexant reduced the heart rate of spontaneously hypertensive rats, which are considered a model of endogenous, sympathetic hyperactivation that can occur in insomnia or anxiety disorders. Daridorexant had no effect on ultrasound-induced, panic-like, defensive behavior (UIDB). We conclude that daridorexant rather attenuated and did not intensify fear/stress responses in rats. It was effective in models that simulate endophenotypes that are specific for post-traumatic stress, obsessive-compulsive, and social anxiety disorder.

The influence of sleep disorders on perioperative neurocognitive disorders among the elderly: A narrative review.

This review comprehensively assesses the epidemiology, interaction, and impact on patient outcomes of perioperative sleep disorders (SD) and perioperative neurocognitive disorders (PND) in the elderly. The incidence of SD and PND during the perioperative period in older adults is alarmingly high, with SD significantly contributing to the occurrence of postoperative delirium. However, the clinical evidence linking SD to PND remains insufficient, despite substantial preclinical data. Therefore, this study focuses on the underlying mechanisms between SD and PND, underscoring that potential mechanisms driving SD-induced PND include uncontrolled central nervous inflammation, blood-brain barrier disruption, circadian rhythm disturbances, glial cell dysfunction, neuronal and synaptic abnormalities, impaired central metabolic waste clearance, gut microbiome dysbiosis, hippocampal oxidative stress, and altered brain network connectivity. Additionally, the review also evaluates the effectiveness of various sleep interventions, both pharmacological and nonpharmacological, in mitigating PND. Strategies such as earplugs, eye masks, restoring circadian rhythms, physical exercise, noninvasive brain stimulation, dexmedetomidine, and melatonin receptor agonists have shown efficacy in reducing PND incidence. The impact of other sleep-improvement drugs (e.g., orexin receptor antagonists) and methods (e.g., cognitive-behavioral therapy for insomnia) on PND is still unclear. However, certain drugs used for treating SD (e.g., antidepressants and first-generation antihistamines) may potentially aggravate PND. By providing valuable insights and references, this review aimed to enhance the understanding and management of PND in older adults based on SD.

The Efficacy and Safety Difference Between Daridorexant and Suvorexant

The prevalence of insomnia is rising in today's culture under the influence of many factors. However, experts have long been concerned about the negative consequences and effects of hypnotic medicines. Currently, more and more researchers are focusing on the effects of drugs that target orexin receptors on sleep. Both daridorexant and Suvorexant are two effective dual orexin receptor antagonists in treating insomnia. According to the data collected from Google Scholar, JSTOR, NCBI, and PMC, the comparison of the effectiveness and the abuse potential between daridorexant and suvorexant is concluded. Suvorexant already is a common medicine for patients. The best dose for suvorexant is 30/40mg. Suvorexant has some unserious side-effects like nasopharyngitis. Daridorexant is a relatively new drugs that just enter the market in 2022. It has more function than Suvorexant like improving day-time function and sleep structure. The best dose for daridorexant is 50 mg. Daridorexant has unserious side-effects like fatigue and somnolence.