Ramelteon: a novel hypnotic lacking abuse liability and sedative adverse effects

Ameliorative effects of topical ramelteon on imiquimod-induced psoriasiform inflammation in mice

Psoriasis is a long-lasting, immune-related inflammatory skin disease that affects 2-3% of the global population. It is distinguished by erythematous, silvery, and scaly patches. Ramelteon is a type of melatonin agonist that is used to treat insomnia. It has enhanced non-classical immunomodulatory and anti-inflammatory activities. The aim of the study is to assess the ameliorative effects of topical ramelteon on imiquimod (IMQ)-aggravated psoriasiform-like dermatosis in mice. The 32 albino mouse males were placed into six groups of eight animals, all of them. With the exception of the control group, all groups gained a once-a-day regimen of topical imiquimod 5% cream at a dose of 62.5 mg for eight uninterrupted days, while mice in the control group gained vaseline-based ointment alternately. Immediately after an 8-day induction period in the imiquimod group, mice in the clobetasol and ramelteon treatment groups obtained a twice-daily regimen of topical clobetasol propionate 0.05% ointment and 0.1% ointment, respectively, for a further 8 days. This extends the total duration of the experimental study to 16 continuous days. The findings of our study found that ramelteon significantly mitigated the concentrations of inflammatory cytokines in the skin tissue, including interleukin (IL)-6, IL-17A, IL-23, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF), as well as the scores associated with psoriatic lesions, including erythema, scaling, skin thickening, ear thickness, and overall cumulative PASI scores. Additionally, the anti-inflammatory impact of ramelteon was achieved by markedly increasing IL-10 levels in the skin tissue and correcting cutaneous histopathological alterations. Ramelteon ointment (0.1%) was comparable to that of clobetasol (0.05%) ointment in alleviating a mouse model of imiquimod-induced psoriasiform inflammation; this is probably due to its potential anti-inflammatory and immunomodulatory activities. Therefore, ramelteon could be a good additive option for therapeutic management of immune-triggered inflammatory conditions such as psoriasis.

Molecular mechanisms of Baihedihuang decoction as a treatment for breast cancer related anxiety: A network pharmacology and molecular docking study

BACKGROUND

The therapeutic effects of a combination of Chinese medicines called Baihedihuang decoction (BD) have been clinically verified, although its molecular targets in breast cancer related anxiety remain unknown.

AIM

To explore the molecular mechanisms of BD for breast cancer related anxiety treatment.

METHODS

We used the Traditional Chinese Medicine Systems Pharmacology database to screen the active ingredients and potential targets of BD, and constructed the "drug-ingredient-target" network map with the help of Cytoscape 3.8 software. Also, we used the Online Mendelian Inheritance in Man, DrugBank, and Gencards databases to collect the disease targets of breast cancer related anxiety, and used the STRING platform to perform protein interaction analysis and construct the protein-protein interaction network. Metascape platform was used for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of key targets. Molecular docking technology was used to verify the drug component/target disease network.

RESULTS

We screened 16 active ingredients of BD for breast cancer related anxiety, with 113 target proteins. There are 931 disease targets of breast cancer related anxiety, and finally, 43 key targets and 305 Kyoto Encyclopedia of Genes and Genomes pathways were generated. The main active ingredients of BD for breast cancer related anxiety are verbascoside, β-sitosterol, stigmasterol, catalpol, etc. CDK2, TP53, HTR2A, ESR1, etc. are its key targets, and the main involved signaling pathways may include neuroactive ligand-receptor interaction pathway, 5-hydroxytryptaminergic synapse, P53 signaling pathway, cGMP-PKG signaling pathway, the cAMP signaling pathway, etc. Finally, molecular docking was performed with Vina software to validate the key active ingredients in BD with the selected key action targets. The molecular docking results showed that verbascoside, β-sitosterol, stigmasterol and CDK2 could stably bind and interact through amino acid residues SER249, ARG260, PRO228, ALA282, SER276, LYS273, ASN272, etc.

CONCLUSION

The therapeutic effect of BD for breast cancer related anxiety is multi-level, multi-target, and multi-pathway. The findings of this study provide ideas and basis for further research.

Residual effects of low dose of suvorexant, zolpidem, and ramelteon in healthy elderly subjects: A randomized double‐blind study

Introduction

Methods

Result

Conclusion

Melatonin drugs inhibit SARS-CoV-2 entry into the brain and virus-induced damage of cerebral small vessels

COVID-19 is a complex disease with short- and long-term respiratory, inflammatory and neurological symptoms that are triggered by the infection with SARS-CoV-2. Invasion of the brain by SARS-CoV-2 has been observed in humans and is postulated to be involved in post-COVID state. Brain infection is particularly pronounced in the K18-hACE2 mouse model of COVID-19. Prevention of brain infection in the acute phase of the disease might thus be of therapeutic relevance to prevent long-lasting symptoms of COVID-19. We previously showed that melatonin or two prescribed structural analogs, agomelatine and ramelteon delay the onset of severe clinical symptoms and improve survival of SARS-CoV-2-infected K18-hACE2 mice. Here, we show that treatment of K18-hACE2 mice with melatonin and two melatonin-derived marketed drugs, agomelatine and ramelteon, prevents SARS-CoV-2 entry in the brain, thereby reducing virus-induced damage of small cerebral vessels, immune cell infiltration and brain inflammation. Molecular modeling analyses complemented by experimental studies in cells showed that SARS-CoV-2 entry in endothelial cells is prevented by melatonin binding to an allosteric-binding site on human angiotensin-converting enzyme 2 (ACE2), thus interfering with ACE2 function as an entry receptor for SARS-CoV-2. Our findings open new perspectives for the repurposing of melatonergic drugs and its clinically used analogs in the prevention of brain infection by SARS-CoV-2 and COVID-19-related long-term neurological symptoms.

Clinical management of withdrawal from benzodiazepine anxiolytic and hypnotic medications

Benzodiazepines continue to be prescribed widely in the management of patients with insomnia or anxiety disorders, despite the availability and acceptability of alternative pharmacological and psychological treatments. Many patients will experience adverse effects during treatment and considerable distress when the dosage is reduced and stopped. Management of benzodiazepine withdrawal includes measures to prevent the development of dependence, careful attention to underlying medical conditions, medication consolidation and gradual dosage reduction, accompanying psychological interventions, occasional prescription of concomitant medication, and relapse prevention with on-going support to address psychosocial stressors. There are needs for easier patient access to services with refined expertise and for further research to optimise strategies for preventing dependence and facilitating withdrawal.

Therapeutic potential of melatonin and melatonergic drugs on K18-hACE2 mice infected with SARS-CoV-2

As the COVID-19 pandemic grows, several therapeutic candidates are being tested or undergoing clinical trials. Although prophylactic vaccination against SARS-CoV-2 infection has been shown to be effective, no definitive treatment exists to date in the event of infection. The rapid spread of infection by SARS-CoV-2 and its variants fully warrants the continued evaluation of drug treatments for COVID-19, especially in the context of repurposing of already available and safe drugs. Here, we explored the therapeutic potential of melatonin and melatonergic compounds in attenuating COVID-19 pathogenesis in mice expressing human ACE2 receptor (K18-hACE2), strongly susceptible to SARS-CoV-2 infection. Daily administration of melatonin, agomelatine, or ramelteon delays the occurrence of severe clinical outcome with improvement of survival, especially with high melatonin dose. Although no changes in most lung inflammatory cytokines are observed, treatment with melatonergic compounds limits the exacerbated local lung production of type I and type III interferons, which is likely associated with the observed improved symptoms in treated mice. The promising results from this preclinical study should encourage studies examining the benefits of repurposing melatonergic drugs to treat COVID-19 and related diseases in humans.

A Pilot Crossover Trial of Sleep Medications for Sleep-disturbed Methadone Maintenance Patients

OBJECTIVES

Problems with sleep are a common and detrimental occurrence among individuals who receive methadone maintenance for opioid use disorder (OUD).

METHODS

We enrolled ten methadone-maintained persons with insomnia (60% female, mean age 40) in a double-blind trial using actigraphy to confirm daily sleep reports. After a no-medication week to establish baseline sleep patterns, each participant received 1 week each of mirtazapine (30 mg), zolpidem (sustained-release 12.5 mg), mirtazapine (30 mg IR) plus zolpidem (10 mg), and placebo, with a washout week between each medication week. Study medication order was randomized so that the order of each 1-week medication treatment was different for each participant, but all participants received all 4 regimens.

RESULTS

We found that mirtazapine alone improved total sleep (mean 23 minutes), sleep latency (mean 23 minutes), and sleep efficiency (mean 3%), surpassing the other regiments.

CONCLUSIONS

This pilot work suggests that mirtazapine is worthy of further testing as a sleep aid for persons with OUD receiving methadone maintenance.

Evaluating lemborexant for the treatment of insomnia

INTRODUCTION

Insomnia is a complex sleep disorder that compromises quality of life and affects approximately 10% of the general population. Insomnia, defined as trouble initiating or maintaining sleep associated with impaired daytime function or distress, is treated using a comprehensive approach comprised of cognitive behavioral therapy and pharmacotherapy. Lemborexant, a dual orexin receptor antagonist, is a new pharmacotherapeutic option recently approved for the treatment of insomnia.

AREAS COVERED

Here, the authors describe lemborexant, assess its efficacy and safety profile in clinical trials, and evaluate its role in the current insomnia treatment landscape.

EXPERT OPINION

Lemborexant may offer an improved treatment option compared with other pharmacotherapies for insomnia because it is effective both over the long term and over a wide range of outcome measures. Importantly, lemborexant improves latency to sleep onset and sleep maintenance and is able to help people who experience early morning awakenings. Safety data reveal that lemborexant has minimal residual effects on morning alertness or next day function, and that patients are able to respond to an external auditory stimulus in the middle of the night. In conclusion, lemborexant represents a new, effective, and well-tolerated medication for patients with insomnia.

Comparative efficacy and acceptability of pharmacological interventions for the treatment and prevention of delirium: A systematic review and network meta-analysis

We performed a network meta-analysis to build clear hierarchies of efficacy and tolerability of pharmacological interventions for the treatment and prevention of delirium. Electronic databases including PubMed, Google Scholar, Embase, Cochrane Central Register of Controlled Trials, PsycINFO, and MEDLINE were searched published up to February 22, 2019. A total of 108 randomized controlled trials (RCTs) investigating pharmacotherapy on delirium were included for analysis, and the strength of evidence (SoE) was evaluated for critical outcomes. In terms of treatment, quetiapine (low SoE), morphine (low SoE), and dexmedetomidine (moderate SoE) were effective in the intensive care unit (ICU) patients. In terms of prevention, dexmedetomidine (high SoE) and risperidone (high SoE) significantly reduced the incidence of delirium in ICU surgical patients, while ramelteon (high SoE) reduced the incidence of delirium in ICU medical patients. Despite the efficacy, dexmedetomidine and risperidone demonstrated higher drop-out rate (moderate to high SoE). Haloperidol and other antipsychotics, except for quetiapine and risperidone, showed no benefit. None of the agents showed benefit in non-ICU patients. In conclusion, dexmedetomidine may be a drug of choice for both treating and preventing delirium of the ICU and postsurgical patients. However, it may be less tolerable, and side-effects should be adequately managed. Current evidence does not support the routine use of antipsychotics. For medical patients, oral ramelteon might be useful for prevention.

Effect of add-on ramelteon therapy on sleep and circadian rhythm disruption in patients with schizophrenia: A randomized controlled trial

The sleep and circadian rhythm disruptions in schizophrenia are attributed to a decrease in nocturnal melatonin level which may worsen if treated with conventional sedative drugs. This study was planned to evaluate the effects of add-on ramelteon on sleep and circadian rhythm disturbances in schizophrenia. A randomized, rater-blinded clinical trial was conducted on 120 patients with schizophrenia. Patients were categorized into predominantly positive (PG) or negative (NG) symptoms depending on Positive and Negative Syndrome Scale (PANSS) scoring, and then they were randomized into control (haloperidol/risperidone) or test (add-on ramelteon) groups. After recruitment, baseline serum melatonin, serum AANAT, urinary melatonin and Pittsburgh Sleep Quality Index (PSQI) were evaluated. Patients were reassessed after 4 weeks of therapy with antipsychotics with or without ramelteon. A significantly greater increase in night-time melatonin level (PG: 10·19; 95%CI: 1·42 to 18·97; p = 0·024; NG: 18·74; 95%CI: 8·48 to 29·0; p = 0·001), decrease in PSQI scores (PG: -1·57; 95%CI: -2·59 to -0·55; p = 0·003; NG: -2·49; 95%CI: -4·59 to -0·39; p = 0·021), increase in urinary melatonin (PG: 0·20; 95% CI: 0·056 to 0·35; p = 0·008; NG :0·15; 95% CI: 0·01 to 0·29; p = 0·034), increase in serum AANAT (PG: 4·61; 95%CI: 1·34 to 7·87; p = 0·007; NG:3·46; 95%CI: 1·30 to 5·63; p = 0·002) and improvement in PANSS score were found in patients receiving add-on ramelteon. The increase in serum melatonin and decrease in PSQI score were greater with predominantly negative symptom group in comparison to positive symptom group. Ramelteon may be considered as an add-on therapy with antipsychotic drugs for sleep and circadian rhythm disturbances in schizophrenia.

Effects of hypnotics on prefrontal cortex activity during a verbal fluency task in healthy male subjects: A near-infrared spectroscopy study

OBJECTIVE

To assess the effects of hypnotics on prefrontal cortex activity in healthy subjects using near-infrared spectroscopy (NIRS) in a double-blind, placebo-controlled crossover trial.

METHODS

Eighteen healthy males received acute doses of ramelteon (8 mg), triazolam (0.125 mg), or placebo in a predetermined randomization schedule, with a washout period of more than 1 week. All subjects performed a verbal fluency task during NIRS assessments at baseline and at 1 and 4 hr post-dose. The number of words correctly generated during the task (behavioral performance) and scores on the Stanford Sleepiness Scale (SSS) were also recorded at each test time.

RESULTS

Compared with the placebo, triazolam (0.125 mg) significantly decreased oxyhemoglobin (oxy-Hb) concentration change in NIRS during the posttask period and significantly increased behavioral performance, whereas triazolam (0.125 mg) and ramelteon (8 mg) significantly increased SSS scores.

CONCLUSIONS

The differential effects of two types of hypnotics on oxy-Hb change measured by NIRS were observed in acute dosing, suggesting that when assessing brain activity of patients with psychiatric disorders, researchers should consider how certain types of hypnotics can influence brain function. This would also provide useful information to clinicians when prescribing hypnotics suitable for their patients' conditions.

An Open-Labeled Trial of Ramelteon in Idiopathic Rapid Eye Movement Sleep Behavior Disorder

STUDY OBJECTIVES

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by REM sleep without atonia and elaborate motor activity in association with dream mentation. The melatonin receptor agonist ramelteon has been documented as being effective in two patients with secondary RBD. However, there are no reports on ramelteon treatment for idiopathic RBD.

METHODS

In an open-labeled trial, we treated 12 consecutive patients with idiopathic RBD for at least 4 w with 8 mg ramelteon given within 30 min before bedtime.

RESULTS

Ramelteon treatment did not have a clear effect on REM sleep without atonia or an RBD severity scale measured by video-supported polysomnography. However, clinical assessment using a visual analog scale showed a trend toward significance and there were also definitely positive changes in some individual cases. Ramelteon was well tolerated in most patients, with minor side effects.

CONCLUSIONS

Considering that ramelteon is associated with few side effects, further study may ascertain whether patients with RBD could be effectively treated by ramelteon, especially when clonazepam may not be suitable due to its side effects.

COMMENTARY

A commentary on this article appears in this issue on page 643.

Ramelteon-induced nightmares: A case report

Ramelteon is the only FDA-approved melatonin agonist for treatment of insomnia. It acts on melatonin MT1 and MT2 receptors. We describe a case of a patient who was prescribed ramelteon for insomnia disorder. Shortly after initiation of ramelteon, he described vivid nightmares leading to discontinuation of ramelteon. The nightmares ameliorated with ramelteon discontinuation. Ramelteon is well tolerated with a favorable side-effect profile. No documented cases of nightmares secondary to ramelteon use were found in the literature. The effects of ramelteon on rapid eye movement sleep, the stage of sleep where dreams occur, need to be further explored.

The effects of acute treatment with ramelteon, triazolam, and placebo on driving performance, cognitive function, and equilibrium function in healthy volunteers

RATIONALE

Hypnotics are widely used to treat insomnia but adverse effects of different hypnotics, especially benzodiazepine receptor agonists, are getting more attention lately. The effects of novel hypnotics have not been fully examined.

OBJECTIVE

This study aims to assess the effects of two hypnotics, ramelteon and triazolam, on driving performance, cognitive function, and equilibrium function.

METHODS

In this double-blinded, three-way crossover trial, 17 healthy males received acute doses of 8 mg ramelteon, 0.125 mg triazolam, and placebo. The subjects were administered three driving tasks-road-tracking, car-following, and harsh-braking-using a driving simulator and three cognitive tasks-Continuous Performance Test, N-back Test, and Trail-Making Test-at baseline and at 1 and 4 h post-dosing. The Stanford Sleepiness Scale scores and computerized posturography were also assessed.

RESULTS

In the driving simulations, ramelteon and triazolam increased the number of subjects who slid off the road. Triazolam increased the standard deviation of lateral position compared to ramelteon and placebo at 1 h post-dosing. Ramelteon and triazolam significantly increased the time to complete of Trail-Making Test part A and the environmental area in posturography compared to placebo at 1 and 4 h post-dosing. Ramelteon and triazolam significantly increased subjective sleepiness compared to placebo at 1 h post-dosing.

CONCLUSIONS

Ramelteon may affect road-tracking performance, visual attention and/or psychomotor speed measured by Trail-Making Test part A, and body balance in acute dosing. Lower dose of triazolam also impaired performance worse than ramelteon. Physicians should consider risks and benefits when prescribing both drugs, especially in the initial period of administration.

Pharmacokinetic and pharmacodynamic evaluation of ramelteon : an insomnia therapy

INTRODUCTION

Ramelteon , a selective melatonin receptor agonist, is the first member of a novel class of hypnotics. It is approved for the treatment of insomnia characterized by sleep onset difficulties in the US and Japan, but not in Europe.

AREAS COVERED

The main clinical properties as well as safety issues of ramelteon are described. Relevant publications reporting ramelteon characteristics and its use in insomnia disorder were identified using PubMed and SciFinder databases up to January 2015. Additional information was collected from the US clinical trials database and from Takeda website.

EXPERT OPINION

Despite its high prevalence and economic burden, insomnia disorder remains mostly untreated. Ramelteon has demonstrated sleep-promoting effects in clinical trials and clinical practice, and it is not associated with the adverse effects typical of other class of hypnotics. Its efficacy appears to be relatively modest compared to current insomnia therapeutics, and its use seems restricted to patients with sleep onset difficulties. Assessment of ramelteon effects on sleep quality and maintenance, daytime function and of improvements in comorbid insomnia conditions deserves further studies. The potential application of ramelteon in other pathological conditions could open the way to novel therapeutic approaches as well as to new market opportunities.

Assessment of the abuse liability of a dual orexin receptor antagonist: a crossover study of almorexant and zolpidem in recreational drug users

BACKGROUND

Dual orexin receptor antagonists (DORAs) enable initiation and maintenance of sleep in patients with primary insomnia. Blockade of the orexin system has shown reduction of drug-seeking behavior in animal studies, supporting the role of orexin antagonism as a novel approach for treating substance abuse. Since hypnotics are traditionally associated with misuse, a lack of abuse liability of DORAs would offer significant benefits over current therapies for sleep disorders.

METHODS

In this randomized, crossover, proof-of-concept study, single oral doses of the DORA almorexant (200, 400, and 1,000 mg) were administered to healthy subjects with previous non-therapeutic experience with central nervous system depressants and were compared with placebo and single oral doses of zolpidem (20 and 40 mg), a benzodiazepine-like drug. Subjective measures of abuse potential (visual analog scales [VAS], Addiction Research Center Inventory, and Subjective Drug Value) and objective measures (divided attention [DA]) were evaluated over 24 h post-dose in 33 evaluable subjects.

RESULTS

Drug Liking VAS peak effect (E max; primary endpoint) was significantly higher for all doses of almorexant and zolpidem compared with placebo (p<0.001). Almorexant 200 mg showed significantly less 'Drug Liking' than both zolpidem doses (p<0.01), and almorexant 400 mg had smaller effects than zolpidem 20 mg (p<0.05), while almorexant 1,000 mg was not different from either zolpidem dose. Results were similar for other subjective measures, although almorexant generally showed smaller negative and perceptual effects compared with zolpidem. Almorexant also showed less cognitive impairment compared with zolpidem on most DA endpoints.

CONCLUSION

This study in humans investigating single doses of almorexant is the first to explore and show abuse liability of a DORA, a class of compounds that is not only promising for the treatment of sleep disorders, but also of addiction.

Orexin receptor antagonists as therapeutic agents for insomnia

Insomnia is a common clinical condition characterized by difficulty initiating or maintaining sleep, or non-restorative sleep with impairment of daytime functioning. Currently, treatment for insomnia involves a combination of cognitive behavioral therapy (CBTi) and pharmacological therapy. Among pharmacological interventions, the most evidence exists for benzodiazepine (BZD) receptor agonist drugs (GABAA receptor), although concerns persist regarding their safety and their limited efficacy. The use of these hypnotic medications must be carefully monitored for adverse effects. Orexin (hypocretin) neuropeptides have been shown to regulate transitions between wakefulness and sleep by promoting cholinergic/monoaminergic neural pathways. This has led to the development of a new class of pharmacological agents that antagonize the physiological effects of orexin. The development of these agents may lead to novel therapies for insomnia without the side effect profile of hypnotics (e.g., impaired cognition, disturbed arousal, and motor balance difficulties). However, antagonizing a system that regulates the sleep-wake cycle may create an entirely different side effect profile. In this review, we discuss the role of orexin and its receptors on the sleep-wake cycle and that of orexin antagonists in the treatment of insomnia.

Age and Gender Effects on the Pharmacokinetics and Pharmacodynamics of Ramelteon, a Hypnotic Agent Acting via Melatonin Receptors MT1and MT2

Effects of age and gender on the pharmacokinetics and pharmacodynamics of ramelteon, a hypnotic acting via binding to melatonin MT(1) and MT(2) receptors, were evaluated in healthy young (18-34 years) and elderly (63-79 years) volunteers. Part 1 evaluated the pharmacokinetics of open-label oral ramelteon, 16 mg. Part 2 was a double-blind, randomized, 2-trial crossover pharmacodynamic study of 16-mg ramelteon and matching placebo. Ramelteon clearance was significantly reduced in elderly vs young volunteers (384 vs 883 mL/min/kg, P<.01) and half-life significantly increased (1.9 vs 1.3 h, P<.001). Gender did not significantly influence clearance or half-life. Ramelteon was extensively transformed to its hydroxylated M-II metabolite, with serum AUC values averaging about 30 times those of the parent drug. Compared to placebo, ramelteon increased self- and observer-rated sedation, but age and gender did not influence the magnitude of the ramelteon-placebo difference. Ramelteon did not significantly impair digit-symbol substitution test performance or impair information acquisition and recall. Thus, the reduced clearance and higher serum levels of ramelteon in elderly subjects were not associated with enhanced pharmacodynamic effects. The usually recommended clinical dose of ramelteon (8 mg) does not require modification based on age or gender.

Pediatric sleep pharmacology

This article reviews common sleep disorders in children and pharmacologic options for them. Discussions of pediatric sleep pharmacology typically focus on treatment of insomnia. Although insomnia is a major concern in this population, other conditions of concern in children are presented, such as narcolepsy, parasomnias, restless legs syndrome, and sleep apnea.

Insomnia pharmacotherapy

The benzodiazepine receptor agonists (BzRAs) a melatonin receptor agonist and a histamine antagonist have all been approved as hypnotics. Beyond their differing mechanisms of action, they have differences in pharmacokinetics, and among the BzRAs differences in receptor subtype affinity and formulations, which provides the physician with broad options for tailoring therapy to each patient's specific needs. Consistent with their specific pharmacokinetics and formulations, these Food and Drug Administration-approved hypnotics have been shown to improve sleep with no evidence of tolerance development in long-term use. In addition, emerging data indicate these drugs also improve aspects of daytime function. Their side effects are either associated with the direct sedating effects of the drugs, doses greater than clinical doses, or a combination with alcohol or other sedating drugs. Anxiolytic BzRAs, sedating antidepressants and antipsychotics have been used off-label as hypnotics. However, in the absence of information regarding their dose range for efficacy and safety, their use as hypnotics is ill-advised.

Ramelteon in the treatment of chronic insomnia: systematic review and meta-analysis

OBJECTIVE

As a melatonin receptor agonist, ramelteon has been approved in the United States as a treatment for insomnia. As a potential alternation, ramelteon should be further evaluated in different doses and populations. This systematic review with meta-analysis aims to determine the efficacy and safety of ramelteon in the treatment of chronic insomnia.

METHODS

We systematically searched and identified in Medline, Embase, PsycINFO and Cochrane Library until September 2011. We only included randomised controlled trials focused on ramelteon, vs. placebo, or any other treatment for patients with chronic insomnia. Data were extracted and evaluated by two independent investigators. If neither clinical nor statistical heterogeneity was found, we pooled results using a fixed-effect model.

RESULTS

Eight studies were selected to include from 175 identified references. There were significant improvements in all the outcomes (subjective and polysomnographic sleep latency, total sleep time and latency to REM), except for the percentage of REM. By subgroup analysis, subjective sleep latency was reduced only in the patients of 18-64 years old, without in the patients over 65 years old. For the safety, ramelteon was not associated with higher risk ratio of any frequent adverse events comparing with control.

CONCLUSION

The efficacy and safety of ramelteon are promising for the chronic insomnia patients. More researches are required for robust conclusions, particularly well-designed; double-blind randomised controlled trials with higher doses of ramelteon (32 or 64 mg) for the older population comparing with other sedative hypnotics.

Pharmacotherapy of insomnia

INTRODUCTION

Insomnia is one of the most prevalent sleep disorders in developed countries, being surpassed only by chronic sleep deprivation. Patients with insomnia tend to have an altered quality of life, impaired daytime functioning and an increased risk of work accidents and motor vehicle crashes. Insomnia is commonly associated with chronic medical conditions, metabolic illnesses and mental disorders (such as depression and anxiety), with which there is a dual, reciprocal relationship.

AREAS COVERED

This paper focuses on current pharmacotherapy options for the treatment of insomnia, particularly benzodiazepine receptor agonists, which nowadays represent the mainstay of hypnotic therapy. The melatonin receptor antagonist, ramelteon, is reviewed (an alternative for some patients with only sleep-onset difficulty), as are sedating antidepressants, which are commonly used 'off-label' to treat insomnia, despite limited efficacy data and potential significant safety concerns. Orexin (OX) antagonists are also discussed, especially those that block OX2 or both OX1 and OX2 receptors, as these are the most promising new agents for the treatment of insomnia, with encouraging results in preliminary clinical trials.

EXPERT OPINION

Research to evaluate and formulate treatments for insomnia is often complicated by the fact that insomnia is usually of multifactorial etiology. Understanding the molecular and receptor mechanisms involved in promoting sleep in varied disorders could provide future approaches in new drug development. In the long term, more randomized controlled trials are needed to assess both short-term and long-term effects of these medications and their efficacy in comorbid diseases that affect sleep quality or quantity.

Efficacy and tolerability of ramelteon in a double-blind, placebo-controlled, crossover study in Japanese patients with chronic primary insomnia

The aim of this study was to evaluate the efficacy and safety of ramelteon 4, 8, 16 or 32 mg and placebo in Japanese patients with chronic insomnia using a randomized, double-blind, five-period crossover design. A total of 65 Japanese patients with chronic primary insomnia received ramelteon or placebo for two nights each in sleep laboratories. Changes in sleep parameters were assessed objectively by polysomnography and subjectively by postsleep questionnaires. Safety and tolerability was evaluated by assessment of the occurrence of adverse events, next-day residual effects and laboratory and ECG investigations. Ramelteon 8 and 32 mg significantly shortened the mean latency to persistent sleep in comparison with placebo, and there was a statistically significant trend for linear dose-response for this sleep parameter. Overall changes in sleep architecture were modest (<3% changes vs placebo), with increases in stage 1 and decreases in stage 3/4. Ramelteon was well tolerated, the most common adverse effect being somnolence, which was similar to placebo at doses up to 8 mg, but increased with higher doses. Next-day residual effects occurred no more frequently with ramelteon at any dose than with placebo. When compared with sleep latency data from a similarly-designed US study, there was no evidence of any ethnic differences in the efficacy of ramelteon between Japanese and US patients. Overall, ramelteon 8 mg showed the most favorable balance between sleep-promoting effects and tolerability. The unique efficacy profile of ramelteon, promoting sleep initiation without affecting other sleep parameters, may be due to its circadian shifting effect.

Subjective, psychomotor, and physiological effects of pregabalin alone and in combination with oxycodone in healthy volunteers

Pregabalin is an anticonvulsant drug indicated for neuropathic disorders and fibromyalgia. Some chronic pain patients suffering from these disorders take both this drug and an opioid for pain relief. Pregabalin is a scheduled drug under the Controlled Substances Act. The subjective effects of this drug have not been well-characterized, and the extent to which it alters the subjective effects of opioids has not been studied to the best of our knowledge. Using a double-blind, randomized, crossover design, 16 healthy volunteers were administered (in separate sessions) capsules containing placebo, 75 mg pregabalin, 150 mg pregabalin, 10 mg oxycodone, and 75 mg pregabalin combined with 10 mg oxycodone. Subjective, psychomotor, and physiological measures were assessed during each of the five sessions. Pregabalin produced dose-related increases in some subjective effects and decreased respiration rate, but did not impact on psychomotor performance. Abuse liability-related subjective effects such as drug liking and desire to take the drug again were not increased by either pregabalin dose. Oxycodone produced increases in several subjective effects, including ratings of drug liking. When 75 mg pregabalin was combined with oxycodone some subjective effects were altered relative to placebo, in contrast to when each drug was tested alone. Liking of oxycodone was not increased by 75 mg pregabalin. However, recent studies have suggested that this drug is abused, and we would recommend that further psychopharmacological studies with pregabalin are warranted, including a study assessing its abuse liability across a range of doses in sedative abusers.

Placebo-controlled pilot study of ramelteon for adiposity and lipids in patients with schizophrenia

OBJECTIVE

Few interventions have been successful to prevent or reverse the medical complications associated with antipsychotic agents in the schizophrenia population. In particular, no single agent can correct multiple metabolic abnormalities such as insulin resistance, hyperlipidemia, inflammation, obesity, and fat distribution. We now report a randomized placebo-controlled pilot study to examine the effects of ramelteon on obesity and metabolic disturbances among subjects with schizophrenia.

METHODS

A double-blind, placebo-controlled, 8-week pilot trial was conducted, adding ramelteon 8 mg/d to stable outpatients with schizophrenia. Vital signs and anthropometric measurements, including height, weight, waist circumference, and body fat were assessed, and laboratory assays were tracked to monitor changes in metabolic markers.

RESULTS

Twenty-five subjects were randomly assigned to treatment with study drug or placebo, and 20 subjects were included in the final analysis. Ramelteon did not improve anthropometric measurements, glucose metabolism, and inflammatory markers. There was, however, a significant decrease in total cholesterol and ratio of cholesterol to high-density lipoprotein in the ramelteon group. Although the standard anthropometric measures did not show significant change, the dual-energy x-ray absorptiometry scan showed a trend toward reduction in fat in the abdominal and trunk areas with a moderate effect size.

CONCLUSIONS

Although ramelteon decreased cholesterol, treatment may have to be longer than 8 weeks and with a higher dose for maximal effect of ramelteon for body fat and lipid changes. Future studies are needed for patients with schizophrenia with a larger sample size to fully understand ramelteon's effects on abdominal adiposity and lipids.

Next-day effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on highway driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects

STUDY OBJECTIVES

To evaluate the next-morning residual effects of ramelteon (8 mg), zopiclone (7.5 mg), and placebo on driving performance, memory functioning, psychomotor performance, and mood in healthy adult subjects following bedtime dosing and a middle of the night awakening.

DESIGN

Single-center, randomized, double-blind, double-dummy, placebo-controlled, crossover study.

SETTING

Utrecht University, The Netherlands.

PARTICIPANTS

30 healthy volunteers (15 males and 15 females).

INTERVENTIONS

a single dose of ramelteon (8 mg), zopiclone (7.5 mg), and placebo, administered at bedtime.

MEASUREMENTS

A balance test was performed at night. Other tests were performed the following morning, 8.5 h after administration. Subjects performed a 100-km highway driving test in normal traffic. Primary outcome measure was the standard deviation of the lateral position (SDLP), i.e., the weaving of the car. After driving, cognitive, memory, and psychomotor tests were performed and mood was assessed.

RESULTS

SDLP was significantly increased after the intake of ramelteon (+2.2 cm) and zopiclone (+2.9 cm). Ramelteon and zopiclone produced significant impairment on reaction time (P<0.024) in the Sternberg Memory Scanning Test, slow (P<0.007) and fast (P<0.010) tracking, reaction speed (P<0.015) and tracking (P<0.001) in the Divided Attention Test, and delayed recall (P<0.032) in the Word Learning Test. In contrast to ramelteon, zopiclone additionally impaired performance on the Digit Symbol Substitution Test (P<0.001) and the balance test (P<0.001).

CONCLUSIONS

Ramelteon (8 mg) and zopiclone (7.5 mg) significantly impaired driving performance, cognitive, memory, and psychomotor performance the morning following bedtime administration. In contrast to zopiclone, ramelteon produced no balance impairments. CLINICAL TRIAL IDENTIFIER: NCT00319215 (www.clinicaltrials.gov).

Use of a post-sleep questionnaire-interactive voice response system (PSQ-IVRS) to evaluate the subjective sleep effects of ramelteon in adults with chronic insomnia

OBJECTIVE

Ramelteon is an MT(1)/MT(2) melatonin receptor agonist approved in the US and Japan for the treatment of sleep-onset insomnia. This study evaluated the effects of ramelteon 8mg on patient reported sleep parameters in adults with chronic insomnia in an at-home setting using a post-sleep questionnaire-interactive voice response system (PSQ-IVRS).

METHODS

Adults aged 18-64 years with chronic insomnia were randomized to receive ramelteon 8 mg or placebo nightly for 3weeks. Sleep parameters were assessed via PSQ-IVRS within 60 min of awakening each morning. Adverse effects were collected throughout the study.

RESULTS

A total of 552 subjects (mean age 43.2 years) received treatment (274 ramelteon, 278 placebo). There was a reduction in mean sleep latency at weeks 1, 2, and 3 compared with placebo but none reached statistical significance (-4.1 min, p=0.088 week 1; -2.8 min, p=0.258 week 2; -4.9 min, p=0.060 week 3). There were no significant differences between placebo and ramelteon in other PSQ-IVRS sleep parameters. Only headache (18 [6.5%] placebo, 18 [6.6%] ramelteon) and somnolence (5 [1.8%], 12 [4.4%] ramelteon) occurred in>3% of subjects.

CONCLUSIONS

Use of ramelteon 8 mg in an at-home setting did not demonstrate statistically significant improvements in subjective sleep latency compared with placebo, when measured by PSQ-IVRS.

Melatonin agonists in primary insomnia and depression-associated insomnia: are they superior to sedative-hypnotics?

Current pharmacological treatment of insomnia involves the use of sedative-hypnotic benzodiazepine and non-benzodiazepine drugs. Although benzodiazepines improve sleep, their multiple adverse effects hamper their application. Adverse effects include impairment of memory and cognitive functions, next-day hangover and dependence. Non-benzodiazepines are effective for initiating sleep but are not as effective as benzodiazepines for improving sleep quality or efficiency. Furthermore, their prolonged use produces adverse effects similar to those observed with benzodiazepines. Inasmuch as insomnia may be associated with decreased nocturnal melatonin, administration of melatonin is a strategy that has been increasingly used for treating insomnia. Melatonin can be effective for improving sleep quality without the adverse effects associated with hypnotic-sedatives. Ramelteon, a synthetic analog of melatonin which has a longer half life and a stronger affinity for MT1 and MT2 melatonergic receptors, has been reportedly effective for initiating and improving sleep in both adult and elderly insomniacs without showing hangover, dependence, or cognitive impairment. Insomnia is also a major complaint among patients suffering from depressive disorders and is often aggravated by conventional antidepressants especially the specific serotonin reuptake inhibitors. The novel antidepressant agomelatine, a dual action agent with affinity for melatonin MT1 and MT2 receptors and 5-HT2c antagonistic properties, constitutes a new approach to the treatment of major depressive disorders. Agomelatine ameliorates the symptoms of depression and improves the quality and efficiency of sleep. Taken together, the evidence indicates that MT1/MT2 receptor agonists like ramelteon or agomelatine may be valuable pharmacological tools for insomnia and for depression-associated insomnia.

Pharmacotherapy of insomnia with ramelteon: safety, efficacy and clinical applications

Ramelteon is a tricyclic synthetic analog of melatonin that acts specifically on MT₁ and MT₂ melatonin receptors. Ramelteon is the first melatonin receptor agonist approved by the Food and Drug Administration (FDA) for the treatment of insomnia characterized by sleep onset difficulties. Ramelteon is both a chronobiotic and a hypnotic that has been shown to promote sleep initiation and maintenance in various preclinical and in clinical trials. The efficacy and safety of ramelteon in patients with chronic insomnia was initially confirmed in short-term placebo-controlled trials. These showed little evidence of next-day residual effects, withdrawal symptoms or rebound insomnia. Other studies indicated that ramelteon lacked abuse potential and had a minimal risk of producing dependence or adverse effects on cognitive or psychomotor performance. A 6-month placebo-controlled international study and a 1-year open-label study in the USA demonstrated that ramelteon was effective and well tolerated. Other potential off-label uses of ramelteon include circadian rhythm sleep disorders such as shift-work and jet lag. At the present time the drug should be cautiously prescribed for short-term treatment only.

Pimavanserin tartrate, a 5-HT(2A) receptor inverse agonist, increases slow wave sleep as measured by polysomnography in healthy adult volunteers

OBJECTIVE

Determine the effects of pimavanserin tartrate [ACP-103; N-(4-flurophenylmethyl)-N-(1-methylpiperidin-4-yl)-N'-(4-(2-methylpropyloxy)phenylmethyl)carbamide], a selective serotonin 5-HT(2A) receptor inverse agonist, on slow wave sleep (SWS), other sleep parameters, and attention/vigilance.

METHODS

Forty-five healthy adults were randomized to pimavanserin (1, 2.5, 5, or 20 mg) or placebo in a double-blind fashion (n=9/group). Pimavanserin or placebo was administered once daily in the morning for 13 consecutive days. The effects of pimavanserin were measured after the first dose and again after 13 days. Sleep parameters were measured by polysomnography. Effects on attention/vigilance were measured by a continuous performance task.

RESULTS

Compared to placebo, pimavanserin significantly increased SWS following single and multiple dose administration. Pimavanserin also decreased number of awakenings. PSG variables not affected by pimavanserin included sleep period time, total sleep time, sleep onset latency, number of stage shifts, total time awake, early morning wake, and microarousal index. Changes in sleep architecture parameters, sleep profile parameters, and spectral power density parameters were consistent with a selective increase in SWS. Pimavanserin did not adversely affect performance on the continuous performance test measured in the evening before or morning after polysomnography.

CONCLUSIONS

These data suggest that pimavanserin selectively increases slow wave sleep and decreases awakenings, an effect that does not diminish with repeated administration.

Insomnia medication use and the probability of an accidental event in an older adult population

Objective:

This study examined the risk of accidental events in older adults prescribed a sedating antidepressant, long-acting benzodiazepine, short-acting benzodiazepine, and nonbenzodiazepine, relative to a reference group (selective melatonin receptor agonist).

Methods:

This was a retrospective cohort analysis of older adults (≥65 years) with newly initiated pharmacological treatment of insomnia. Data were collected from the Thomson MarketScan^® Medicare Supplemental and Coordination of Benefits databases (January 1, 2000, through June 30, 2006). Probit models were used to evaluate the probability of an accidental event.

Results:

Data were analyzed for 445,329 patients. Patients taking a long-acting benzodiazepine (1.21 odds ratio [OR]), short-acting benzodiazepine (1.16 OR), or nonbenzodiazepine (1.12 OR) had a significantly higher probability of experiencing an accidental event during the first month following treatment initiation compared with patients taking the reference medication (P < 0.05 for all). A significantly higher probability of experiencing an accidental event was also observed during the 3-month period following the initiation of treatment (1.62 long-acting benzodiazepine, 1.60 short-acting benzodiazepine, 1.48 nonbenzodiazepine, and 1.56 sedating antidepressant; P < 0.05).

Conclusions:

Older adults taking an SAD or any of the benzodiazepine receptor agonists appear to have a greater risk of an accidental event compared with a reference group taking an MR.

Healthy brain aging: what has sleep got to do with it?

Sleep plays an important role in learning, memory encoding, and cognition. Insufficient quantity or quality of sleep leads not only to short-term neurocognitive dysfunction but also to permanent changes to the central nervous system. Sleep disorders are common in the geriatric population. The hypoxemia and sleep fragmentation resulting from obstructive sleep apnea are the most likely pathophysiology responsible for damage to the brain. Because treatment of these sleep disorders can lead to improved cognitive function, it is becoming increasingly important for physicians to be able to correctly recognize and treat these disorders in patients presenting with memory or cognitive complaints.

Neurophysiology of sleep and wakefulness: basic science and clinical implications

Increased attention to the prevalence of excessive sleepiness has led to a clear need to treat this symptom, thus reinforcing the need for a greater understanding of the neurobiology of sleep and wakefulness. Although the physiological mechanisms of sleep and wakefulness are highly interrelated, recent research reveals that there are distinct differences in the active brain processing and the specific neurochemical systems involved in the two states. In this review, we will examine the specific neuronal pathways, transmitters, and receptors composing the ascending arousal system that flow from the brainstem through the thalamus, hypothalamus, and basal forebrain to the cerebral cortex. We will also discuss the mutually inhibitory interaction between the core neuronal components of this arousal system and the sleep-active neurons in the ventrolateral preoptic nucleus, which serves as a brainstem-switch, regulating the stability of the sleep-wake states. In addition, we will review the role of homeostatic and circadian processes in the sleep-wake cycle, including the influence of the suprachiasmatic nucleus on coordination of sleep-wake systems. Finally, we will summarize how the above processes are reflected in disorders of sleep and wakefulness, including insomnia, narcolepsy, disorders associated with fragmented sleep, circadian rhythm sleep disorders, and primary neurological disorders such as Parkinson’s and Alzheimer’s diseases.

Review of insomnia pharmacotherapy options for the elderly: implications for managed care

The prevalence of insomnia in the elderly is significant. If left untreated or inappropriately treated, insomnia may contribute to increased health care resource use. Therefore, better identification and management of insomnia is required for this patient population. The etiology and magnitude of insomnia due to changes in circadian rhythms, comorbid conditions, and pharmaceutical agents are not well documented, and the utilization of over-the-counter and non-Food and Drug Administration (FDA)-approved agents to induce sleep (including antihistamines and ethyl alcohol) have not been studied in a natural setting. Evaluating the actual type of insomnia remains much more art than science for the majority of patients and providers. Another issue to consider in this population involves the relationship between patient and physician and the traditional passive patient role. Nonpharmacologic approaches (ie, cognitive behavioral therapy) for insomnia management are effective and usually are first-line therapy. However, the challenges to implementing these approaches may limit their use, thus necessitating pharmacologic therapy. There are currently 3 FDA-approved drug classes for the treatment of insomnia: benzodiazepines, benzodiazepine receptor agonists, and melatonin receptor agonists. Although all agents in these classes are efficacious, benzodiazepines and benzodiazepine receptor agonists are associated with adverse events that must be considered when treating insomnia in the elderly. Melatonin agonists have a mechanism of action that regulates normal sleep-wake cycles and readjusts circadian rhythms, which may confer a better safety profile than traditional sedative-hypnotics that target gamma-aminobutyric acid receptors. Because the 3 currently approved drug classes for insomnia have similar efficacy, safety considerations should be of paramount importance for the elderly patient; however, additional data are needed to appropriately assess the risk-benefit ratios of each.

Critical appraisal of ramelteon in the treatment of insomnia

Ramelteon is the first member of a novel class of hypnotics and acts as a selective melatonin receptor agonist. In 2005, ramelteon was approved by the US Food and Drug Administration for the treatment of insomnia characterized by sleep onset problems. Its unique mechanism of action made it a promising candidate compared with the widely used hypnotics that act on the benzodiazepine receptor complex. Several studies have examined its efficacy and safety as a hypnotic agent. The primary efficacy of ramelteon was found to lie in a decrease in latency to persistent sleep, as measured by polysomnographic tests. Other sleep-related measures, such as total sleep time and number of nightly awakenings, show less pronounced improvement when treated with ramelteon. In addition, no rebound insomnia or abuse potential was observed in clinical studies. Although additional studies are necessary, current data on the acute and next-morning effects of ramelteon did not indicate cognitive or psychomotor impairment. Overall, ramelteon is safe and well tolerated, although some questions remain regarding its long-term efficacy and safety. These issues and possibilities for use in other patient groups should be addressed in future research.

Principles of laboratory assessment of drug abuse liability and implications for clinical development

Abuse liability testing plays an important role in informing drug development, regulatory processes, and clinical practice. This paper describes the current "gold standard" methodologies that are used for laboratory assessments of abuse liability in non-human and human subjects. Particular emphasis is given to procedures such as non-human drug discrimination, self-administration, and physical dependence testing, and human dose-effect abuse liability studies that are commonly used in regulatory submissions to governmental agencies. The potential benefits and risks associated with the inclusion of measures of abuse liability in industry-sponsored clinical trials is discussed. Lastly, it is noted that many factors contribute to patterns of drug abuse and dependence outside of the laboratory setting and positive or negative signals in abuse liability studies do not always translate to high or low levels of actual abuse or dependence. Well-designed patient and physician education, pharmacovigilance, and postmarketing surveillance can reduce the diversion and misuse of drugs with abuse liability and can effectively foster the protection and promotion of public health.