Preventive Effects of Suvorexant on Delirium: A Randomized Placebo-Controlled Trial

Involvement of orexinergic system in psychiatric and neurodegenerative disorders: A scoping review

Orexin is a neuropeptide secreted from lateral hypothalamus and pre-frontal cortex concerned in the wakefulness and excitement. This study aimed to review the possible neurobiological effect of orexin. A diversity of search strategies was adopted and assumed which included electronic database searches of Medline and PubMed using MeSH terms, keywords, and title words during the search. Orexin plays a vital role in activation of learning, memory acquisition, and consolidation through activation of monoaminergic system, which affect cognitive flexibility and cognitive function. Orexin stimulates adrenocorticotropin and corticosteroid secretions via activation of central corticotropin-releasing hormone. Cerebrospinal fluid (CSF) and serum orexin serum levels are reduced in depression, schizophrenia, and narcolepsy. However, high orexin serum levels are revealed in drug addictions. Regarding neurodegenerative brain diseases, CSF and serum orexin serum levels are reduced Parkinson disease, Alzheimer dementia, Huntington's disease, amyotrphic lateral sclerosis, and multiple sclerosis. Orexin antagonist leads to significant reduction of sympathetic over-activity during withdrawal syndrome. As well, orexin antagonist improves sleep pattern. Orexinergic system is involved in the different psychiatric and neurological disorders; therefore, targeting of this system could be possible novel pathway in the management of these disorders. In addition, measurement of CSF and serum orexin levels might predict the relapse and withdrawal of addict patients.

The role of suvorexant in the prevention of delirium during acute hospitalization: A systematic review

PURPOSE

To assess the efficacy and safety of suvorexant for the prevention of delirium during acute hospitalization.

MATERIALS AND METHODS

Pubmed (1946 to December 2019) and Embase (1947 to December 2019) were queried using the search term combination: delirium, confusion, cognitive defect, encephalopathy, critically ill patient, critical illness, or hospitalization and suvorexant or orexin receptor antagonist. Studies analyzed for relevance evaluated clinical outcomes of patients treated with suvorexant for prevention of delirium. Studies appropriate to the objective were evaluated, including two randomized controlled trials and four retrospective studies.

RESULTS

In acutely hospitalized patients, treatment with suvorexant 15 to 20 mg alone or in combination with ramelteon resulted in a reduction in development of delirium, time until delirium onset, and length of hospital stay. When assessed, suvorexant was well tolerated and adverse effects were no worse than placebo.

CONCLUSION

Based on the reviewed literature, suvorexant has shown positive outcomes in the prevention of delirium during an acute hospitalization. Larger trials comparing the efficacy of suvorexant to other sleep modulating options are necessary to further delineate its role for the prevention of delirium.

Pre-operative hemoglobin level and use of sedative-hypnotics are independent risk factors for post-operative delirium following total knee arthroplasty

BACKGROUND

Delirium is a well-known complication following surgery, especially with the increasing age of patients undergoing surgery. The increasing demands resulting from a prolonged healthy life expectancy has resulted in more arthroplasties despite their age and existing comorbidities. The purpose of this study is to explore the various risk factors that may contribute to delirium in unilateral and bilateral total knee arthroplasties in the elderly population.

METHODS

170 patients who underwent unilateral or bilateral total knee arthroplasties were analyzed retrospectively for delirium. Age, sex, comorbidities, use of sedative-hypnotics, peri-operative blood loss, pre- and post-operative laboratory blood test results were investigated and analyzed.

RESULTS

The incidence of post-operative delirium was 6.5% (11 out of 170 patients) with a mean age of 79.5 (± 6.9) years, compared to 73.0 (± 9.0) years in the non-delirium group. Higher age, use of sedative-hypnotics, low pre-operative Hb and Ht, low post-operative Hb, Ht and BUN were observed in the delirium group. Multivariate logistic regression analysis identified that the use of sedative-hypnotics and pre-operative Hb level were independent risk factors for post-operative delirium after TKA. The odds ratios for the use of sedative-hypnotics and pre-operative Hb level were 4.6 and 0.53, respectively. Receiver operating characteristic curve analysis showed that pre-operative Hb of less than 11.1 g/dL was a predictor for the development of delirium, with a sensitivity of 54.6% and a specificity of 91.6%.

CONCLUSION

Patients with a pre-operative Hb level of < 11.1 g/dL or those using sedative-hypnotics are associated with post-operative delirium. Peri-operative management and preventative measures are therefore needed to reduce the risks of post-operative delirium in such patients.

Considerations and Current Trends in the Management of the Geriatric Patient on a Consultation-Liaison Service

PURPOSE OF REVIEW

To provide consultation-liaison psychiatrists with an updated resource that can assist in the treatment and management of geriatric patients.

RECENT FINDINGS

The current available literature has not shown any differences in efficacy between haloperidol and second-generation antipsychotics in patients with delirium. When considering relative advantages of forms of antipsychotic administration, there is no support for a superior safety profile of oral compared to intramuscular or intravenous administration. A recent meta-analysis of four randomized controlled trials concluded that when melatonin was administered to older age patients on medical wards, it significantly prevented the incidence of delirium when compared with the control group. While suvorexant administered nightly to elderly patients in acute care settings may lower the incidence of delirium, larger studies are needed to confirm this finding. Despite the black box warning of increased mortality risk in older patients with dementia, antipsychotics may be used with caution by the consultation-liaison (CL) psychiatrist to treat the neuropsychologic symptoms of dementia including hallucinations and psychosis in the hospital setting. While antidepressant studies have focused primarily on citalopram and escitalopram in the treatment of agitation in the setting of dementia, these two medications have not been adequately compared directly to other SSRIs for this condition. It is therefore not clear whether citalopram and escitalopram are more efficacious in treating agitation in the setting of dementia when compared to other SSRIs. While the evidence supporting trazodone's use is limited, it is generally well tolerated and is an option as a PRN for irritability and agitation in patients with Alzheimer's and mixed dementia. While there is some evidence to support the use of acetylcholinesterase inhibitors for treating cognitive impairments and hallucinations in Lewy body dementia, the usefulness of these agents in other forms of dementia is not well studied, and those studies did not show any benefit in the management of acute agitation. It is important to note that memantine can cause or exacerbate agitation and may be the cause of behavioral dysregulation. There is no evidence to support the routine use of benzodiazepines for behavioral improvement in patients with dementia. Escitalopram and citalopram do have a unique pharmacokinetic properties in the sense that they have been found to have 50-56% plasma protein binding, compared to sertraline, fluoxetine, and paroxetine (95% or more). Pooled analyses suggest that antidepressants are more effective than placebo in reducing the symptoms of post-stroke depression. SSRIs are considered first-line antidepressants in stroke patients, who are often elderly with underlying cardiovascular problems. Although treatment with SSRIs is recommended for post-stroke depression, there are no studies providing conclusive data on the superiority of a specific drug. Older age is associated with a better outcome from ECT, with remission rates of approximately 73% to 90% in patients over 65 years. ECT is the treatment of choice for patients with psychotic depression, and elderly patients with psychotic depression have been shown to have a higher remission rate and faster time to response than depressed patients without psychotic symptoms. With the average life expectancy increase, it is projected that 19 million people will reach the age of 85 or higher, an increase from 5.5 million in 2010. With an increasing older population, psychiatric consultation in the management of geriatric patients is becoming more necessary. Psychiatrists must be aware of the unique considerations in elderly patients. In this article, we provide evidence-based guidance to the CL psychiatrist on major issues relating to the older age patient, highlighting recent trends in treatment. First, we provide background on the evaluation of the medically hospitalized geriatric patient. As rates of medical and psychiatric illnesses increase with advancing age, elderly patients are more likely to be taking a higher number of medications as compared to younger patients, and physicians must pay special attention to polypharmacy, including side effects and drug interactions in this group. Next, we focus on the diagnosis, management, and unique needs of the geriatric patient presenting with common clinical syndromes of delirium, dementia, and depression. Delirium and dementia are among the most common causes of cognitive impairment in clinical settings yet are often either unrecognized or misdiagnosed as they may have similar signs and symptoms. In addition, depression is prevalent in older adults, especially in those with comorbid medical illness. Depression can be fatal as the rates of suicide are higher in later life than in any other age group. Consultation can improve the management of elderly patients and prevent unnecessary nursing home placement.

Abnormal behaviors during sleep from the viewpoint of sleep epileptology: current and future perspectives on diagnosis

Abnormal behaviors during sleep (ABDS) exhibit a myriad of symptoms. Their underlying diseases are also diverse, which include NREM/REM-related parasomnias, epilepsy and mental disorders. Since ABDS may severely affect a patient’s quality of life, giving an early and accurate diagnosis of the underlying disease (by analyzing video-polysomnographic data during the manifestation of ABDS) is of great importance. However, accurate diagnosis of ABDS is rather difficult. Recently it has been suggested that the pathology of (NREM/REM-related) parasomnias and epilepsy are closely related. In order to unravel the pathophysiological substrate of ABDS, it is essential to develop a novel approach based on sleep epileptology, a field which targets the interface between sleep medicine and epileptology.

Effect of Suvorexant on Nocturnal Delirium in Elderly Patients with Alzheimer's Disease: A Case-series Study

Suvorexant, an orexin receptor antagonist used for insomnia, has been shown to have a preventive effect on delirium in a randomized placebo-controlled trial. However, its effectiveness in the management of nocturnal delirium has not yet been determined. Here we report four cases in which elderly patients with moderate to severe Alzheimer’s disease who developed nocturnal delirium were treated with suvorexant. In case 1, 15 mg suvorexant was initiated to manage nocturnal delirium refractory to antipsychotics, antidepressants, and a Japanese herbal medicine, resulting in immediate sleep improvement. However, treatment discontinuation led to recurrence of symptoms, which were reversed by recommencing suvorexant. In case 2, as antipsychotics used for the treatment of nocturnal delirium were ineffective, 15 mg suvorexant was administered. The patient achieved rapid improvement in sleep. In case 3, the use of atypical antipsychotics for the treatment of nocturnal delirium was contraindicated, as the patient had diabetes. Therefore, 15 mg suvorexant was administered following good outcomes in cases 1 and 2, resulting in immediate sleep improvement. Finally, in case 4, 15 mg suvorexant was used as an initial medication for nocturnal delirium, and the patient showed sleep improvement immediately. Elevated orexin levels in the cerebrospinal fluid are reportedly linked to sleep deterioration in patients with moderate to severe Alzheimer’s disease. The immediate and reproducible action and effectiveness of suvorexant observed in our patients suggest that enhanced cerebral orexin activity might be associated with sleep-wake cycle disturbances due to delirium in elderly patients with Alzheimer’s disease.

Identification of Patients With High Mortality Risk and Prediction of Outcomes in Delirium by Bispectral EEG

BACKGROUND

Delirium is common and dangerous, yet underdetected and undertreated. Current screening questionnaires are subjective and ineffectively implemented in busy hospital workflows. Electroencephalography (EEG) can objectively detect the diffuse slowing characteristic of delirium, but it is not suitable for high-throughput screening due to size, cost, and the expertise required for lead placement and interpretation. This study hypothesized that an efficient and reliable point-of-care EEG device for high-throughput screening could be developed.

METHODS

This prospective study, which measured bispectral EEG (BSEEG) from elderly inpatients to assess their outcomes, was conducted at the University of Iowa Hospitals and Clinics from January 2016 to October 2017. A BSEEG score was defined based on the distribution of 2,938 EEG recordings from the 428 subjects who were assessed for delirium; primary outcomes measured were hospital length of stay, discharge disposition, and mortality.

RESULTS

A total of 274 patients had BSEEG score data available for analysis. Delirium and BSEEG score had a significant association (P < .001). Higher BSEEG scores were significantly correlated with length of stay (P < .001 unadjusted, P = .001 adjusted for age, sex, and Charlson Comorbidity Index [CCI] score) as well as with discharge not to home (P < .01). Hazard ratio for survival controlling for age, sex, CCI score, and delirium status was 1.35 (95% CI,1.04 to 1.76; P = .025).

CONCLUSIONS

In BSEEG, an efficient and reliable device that provides an objective measurement of delirium status was developed. The BSEEG score is significantly associated with pertinent clinical outcomes of mortality, hospital length of stay, and discharge disposition. The BSEEG score better predicts mortality than does clinical delirium status. This study identified a previously unrecognized subpopulation of patients without clinical features of delirium who are at increased mortality risk.

Current controversies and future perspectives on treatment of intensive care unit delirium in adults

Delirium is the most frequent manifestation of acute brain dysfunction in intensive care unit (ICU). Although antipsychotics are widely used to treat this serious complication, recent evidence has emphasized that these agents did not reduce ICU delirium (ICU-D) prevalence and did not improve survival, length of ICU or hospital stay after its occurrence. Of note, no pharmacological strategy to prevent or treat delirium has been identified, so far. In this scenario, new scientific evidences are urgently needed. Investigations on specific ICU-D subgroups, or focused on different clinical settings, and studies on medications other than antipsychotics, such as dexmedetomidine or melatonin, may represent interesting fields of research. In the meantime, because there is some evidence that ICU-D can be effectively prevented, the literature suggests strengthening all the strategies aimed at prevention through no-pharmacological approaches mostly focused on the correction of risk factors. The more appropriate strategy useful to treat established delirium remains the use of antipsychotics managed by choosing the right doses after a careful case-by-case analysis. While the evidence regarding the use of dexmedetomidine is still conflicting and sparse, this drug offers interesting perspectives for both ICU-D prevention and treatment. This paper aims to provide an overview of current pharmacological approaches of evidence-based medicine practice. The state of the art of the on-going clinical research on the topic and perspectives for future research are also addressed.

Validation of the Prediction of Delirium for Intensive Care model to predict subsyndromal delirium

Aim

Subsyndromal delirium is associated with prolonged intensive care unit stays, and prolonged mechanical ventilation requirements. The Prediction of Delirium for Intensive Care (PRE‐DELIRIC) model can predict delirium. This study was designed to verify if it can also predict development of subsyndromal delirium.

Methods

We undertook a single‐center, retrospective observation study in Japan. We diagnosed subsyndromal delirium based on the Intensive Care Delirium Screening Checklist. We calculated the sensitivity and specificity of the PRE‐DELIRIC model and obtained a diagnostic cut‐off value.

Results

We evaluated data from 70 patients admitted to the mixed medical intensive care unit of the Tokyo Medical University Hospital (Tokyo, Japan) between May 2015 and February 2017. The prevalence of subsyndromal delirium by Intensive Care Delirium Screening Checklist was 31.4%. The area under the receiver operating characteristic curve was 0.83 of the PRE‐DELIRIC model for subsyndromal delirium. The calculated cut‐off value was 36 points with a sensitivity of 94.3% and specificity of 57.1%. Subsyndromal delirium was associated with a higher incidence of delirium (odds ratio, 8.81; P < 0.01).

Conclusion

The PRE‐DELIRIC model could be a tool for predicting subsyndromal delirium using a cut‐off value of 36 points.

Addition of Suvorexant to Ramelteon Therapy for Improved Sleep Quality with Reduced Delirium Risk in Acute Stroke Patients

BACKGROUND AND PURPOSE

Delirium in acute stroke is associated with poor clinical outcome. The purpose of this study was to examine the effect of sleep medications on sleep quality and delirium in acute stroke.

METHODS

In this retrospective cohort study, sleep disturbances, and delirium were investigated in acute stroke patients treated in April 2013-March 2017 who were prescribed ramelteon plus either an alpha-aminobutyric acid receptor (GABAR) agonist or a selective dual orexin receptor antagonist (suvorexant).

RESULTS

Of the patients included, 104 received a GABAR agonist and 128 received suvorexant in addition to ramelteon. Patient characteristics did not differ significantly between the groups, except for a higher proportion of cerebral infarction in suvorexant group (P = .033). Subjective sleep quality was significantly improved in suvorexant group compared to GABAR agonist group (difficulty staying asleep: 6.3% versus 34%, P < .001; daytime sleepiness: 33% versus 63%, P < .001). Delirium was significantly less frequent in suvorexant group than GABAR agonist group (7.0% versus 31%, P < .001). The length of hospital stay was significantly shorter in suvorexant group than in GABAR agonist group (in days, 21 [15-29] versus 25 [18-33]; P = .019). Multivariable logistic regression analysis revealed that the addition of suvorexant was significantly associated with a reduced occurrence of delirium (odds ratios .19, 95% confidence interval .085-.43, P < .001).

CONCLUSIONS

Addition of suvorexant to ramelteon therapy, rather than a GABA receptor agonist, can improve subjective sleep quality without inducing delirium in acute stroke patients.

Ability of suvorexant to prevent delirium in patients in the intensive care unit: a randomized controlled trial

Aim

There are no effective, tolerable, and established medications for preventing delirium in critically ill patients admitted to the intensive care unit (ICU). We investigated whether suvorexant was effective in preventing ICU delirium.

Methods

This randomized controlled study evaluated 70 adult patients (age ≥20 years) admitted to the mixed medical ICU of the Tokyo Medical University Hospital (Tokyo, Japan) between May 2015 and February 2017. Patients were randomized using a sealed envelope method to receive either suvorexant (n = 34; 15 mg for elderly patients and 20 mg for younger adults) or conventional treatment (n = 36) for a 7-day period. The primary outcome was delirium incidence based on the definition in the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders.

Results

No significant between-group differences were observed in the demographic or clinical characteristics. Kaplan-Meier estimates revealed that time to delirium onset was significantly longer in the suvorexant group than in the conventional group (P < 0.05).

Conclusion

Suvorexant might be effective in preventing delirium in ICU patients.

An Update on Dual Orexin Receptor Antagonists and Their Potential Role in Insomnia Therapeutics

STUDY OBJECTIVES

Current pharmacological options for the treatment of insomnia insufficiently meet the needs of all insomnia patients. Approved treatments are not consistently effective in improving sleep onset and sleep maintenance, while also having complicated safety profiles. These limitations highlight the unmet need for additional medications and treatment strategies. Initial research suggests that the dual orexin receptor antagonists (DORAs) may offer an additional pharmaceutical option to treat insomnia in some patients.

METHODS

We reviewed the existing literature on dual orexin receptor antagonists in PubMed databases using the search terms "orexin receptor antagonist," "almorexant" "filorexant," "lembroexant" and "suvorexant"; searches were limited to English language primary research articles, clinical trials, and reviews.

RESULTS

Targeting the orexin receptor system for treatment of insomnia offers an additional and alternative pharmacological approach to more common gamma aminobutyric acid agonist sedative hypnotic treatment. Effectiveness is not well established in the current literature; however, the literature does suggest efficacy. Preclinical reports also suggest the potential for treatment in individuals with comorbid Alzheimer disease and insomnia.

CONCLUSIONS

DORAs offer an additional treatment option for insomnia. More clinical trials are needed to robustly evaluate their safety and effectiveness in several subclasses of individuals with insomnia. Given the published literature, head-to-head comparisons to existing treatment for insomnia are warranted.

Preventive Effect of Suvorexant for Postoperative Delirium after Coronary Artery Bypass Grafting

OBJECTIVE

Suvorexant is an orexin receptor antagonist and is effective in inducing sleep. We hypothesized that Suvorexant would reduce the incidence of postoperative delirium (POD) after coronary artery bypass grafting (CABG).

METHODS

We reviewed 88 patients (12 women, mean age: 69.3 ± 2.5 years) who were undergone CABG alone. Patients were divided into two groups; patients received Suvorexant (S group, n = 36), patients not received Suvorexant (N group, n = 52), and the following data were analyzed and compared between two groups.

RESULTS

Intensive Care Unit Delirium Screening Checklist Score was significantly lower in S group compared with N group (N:S = 2.0 ± 1.7:0.8 ± 1.0, p = 0.0003). Although POD was present in 11 of 52 patients (21.2%) in N group, one patient (2.8%) developed in S group (p = 0.008). In S group, both intensive care unit stay (N:S = median 6:5 days, p = 0.001) and hospital stay (N:S = median 23:20 days, p = 0.035) were significantly shorter than in N group.

CONCLUSIONS

Suvorexant might reduce incidence of POD in patients undergone CABG.

Suvorexant is associated with a low incidence of delirium in critically ill patients: a retrospective cohort study

BACKGROUND

Benzodiazepine use is a risk factor for the development of delirium in adult intensive care unit (ICU) patients. Suvorexant is an alternative to benzodiazepines to induce sleep, but the incidence of delirium in critically ill patients is unknown. We undertook this retrospective study to investigate the incidence of delirium in patients who receive suvorexant in the ICU.

METHODS

This retrospective cohort study was conducted in a closed 12-bed ICU at a tertiary teaching hospital. Patients admitted to the ICU for 72 h or longer between January and June 2015 were evaluated for delirium using the Confusion Assessment Method for the Intensive Care Unit tool. We evaluated the incidence of delirium in patients who received suvorexant and those who did not. To adjust for confounding factors, multivariable logistic regression analysis was conducted.

RESULTS

Study subjects included 118 patients, with a median age of 72 years and a median Acute Physiology and Chronic Health Evaluation II score of 18 points. Eighty-two patients (69.5%) were admitted after cardiovascular surgery. In the suvorexant group, there were fewer post-cardiovascular surgical patients and more medical patients. The duration of mechanical ventilation during ICU stay was longer in the suvorexant group, and sedatives and sleep inducers other than suvorexant were used more frequently in the suvorexant group. The incidence of delirium was 43.8% in the suvorexant group and 58.8% in the non-suvorexant group (P = 0.149). After adjustment for risk factors using multivariable logistic regression analysis, suvorexant was associated with a lower incidence of delirium (odds ratio = 0.23, 95% confidence interval: 0.07-0.73; P = 0.012).

CONCLUSIONS

Suvorexant was associated with decreased odds of transitioning to delirium in critically ill patients. The use of suvorexant may lower the incidence of delirium in ICU patients. Future prospective studies are warranted.