Clonidine effects on all-night human sleep: opposite action of low- and medium-dose clonidine on human NREM-REM sleep proportion

Sleep apnea pathophysiology

OBJECTIVE

The purpose of this study is to examine the pathophysiology underlying sleep apnea (SA).

BACKGROUND

We consider several critical features of SA including the roles played by the ascending reticular activating system (ARAS) that controls vegetative functions and electroencephalographic findings associated with both SA and normal sleep. We evaluate this knowledge together with our current understanding of the anatomy, histology, and physiology of the mesencephalic trigeminal nucleus (MTN) and mechanisms that contribute directly to normal and disordered sleep. MTN neurons express γ-aminobutyric acid (GABA) receptors which activate them (make chlorine come out of the cells) and that can be activated by GABA released from the hypothalamic preoptic area.

METHOD

We reviewed the published literature focused on sleep apnea (SA) reported in Google Scholar, Scopus, and PubMed databases.

RESULTS

The MTN neurons respond to the hypothalamic GABA release by releasing glutamate that activates neurons in the ARAS. Based on these findings, we conclude that a dysfunctional MTN may be incapable of activating neurons in the ARAS, notably those in the parabrachial nucleus, and that this will ultimately lead to SA. Despite its name, obstructive sleep apnea (OSA) is not caused by an airway obstruction that prevents breathing.

CONCLUSIONS

While obstruction may contribute to the overall pathology, the primary factor involved in this scenario is the lack of neurotransmitters.

Efficacy and safety of clonidine for the treatment of impulse control disorder in Parkinson's disease: a multicenter, parallel, randomised, double-blind, Phase 2b Clinical trial

BACKGROUND

Impulse control disorders (ICDs) are frequently encountered in Parkinson's disease (PD).

OBJECTIVES

We aimed to assess whether clonidine, an α2-adrenergic receptor agonist, would improve ICDs.

METHODS

We conducted a multicentre trial in five movement disorder departments. Patients with PD and ICDs (n = 41) were enrolled in an 8-week, randomised (1:1), double-blind, placebo-controlled study of clonidine (75 μg twice a day). Randomisation and allocation to the trial group were carried out by a central computer system. The primary outcome was the change at 8 weeks in symptom severity using the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) score. A reduction of the most elevated subscore of the QUIP-RS of more than 3 points without any increase in the other QUIP-RS dimension defined success.

RESULTS

Between 15 May 2019 and 10 September 2021, 19 patients in the clonidine group and 20 patients in the placebo group were enrolled. The proportion difference of success in reducing QUIP-RS at 8 weeks, was 7% (one-sided upper 90% CI 27%) with 42.1% of success in the clonidine group and 35.0% in the placebo group. Compared to patients in the placebo group, patients in the clonidine group experienced a greater reduction in the total QUIP-RS score at 8 weeks (11.0 points vs. 3.6).

DISCUSSION

Clonidine was well tolerated but our study was not enough powerful to demonstrate significant superiority compared to placebo in reducing ICDs despite a greater reduction of total QUIP score at 8 weeks. A phase 3 study should be conducted.

TRIAL REGISTRATION

The study was registered (NCT03552068) on clinicaltrials.gov on June 11, 2018.

Effects of dexmedetomidine on postoperative sleep quality: a systematic review and meta-analysis of randomized controlled trials

STUDY OBJECTIVES

To assess the effect of dexmedetomidine (DEX) on postoperative sleep quality using polysomnography (PSG) to identify possible interventions for postoperative sleep disturbances.

METHODS

An electronic search of PubMed/MEDLINE, EMBASE, Cochrane Library and Web of Science was conducted from database inception to November 20, 2022. Randomized controlled trials (RCTs) on the effect of DEX administration on postoperative sleep quality using PSG or its derivatives were included. No language restrictions were applied. The sleep efficiency index (SEI), arousal index (AI), percentages of stage N1, N2 and N3 of non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep were measured in our meta-analysis.

RESULTS

Five studies, involving 381 participants were included. Administration of DEX significantly improved SEI, lowered AI, decreased the duration of stage N1 sleep and increased the duration of stage N2 sleep compared to placebo groups. There were no significant differences in the duration of stage N3 sleep and REM sleep. DEX administration lowered the postoperative Visual Analogue Scale (VAS) score and improved the Ramsay sedation score with no adverse effect on postoperative delirium (POD). However, high heterogeneity was observed in most of the primary and secondary outcomes.

CONCLUSIONS

Our study provides support for the perioperative administration of DEX to improve postoperative sleep quality. The optimal dosage and overall effect of DEX on postoperative sleep quality require further investigation using large-scale randomized controlled trials.

Dexmedetomidine in Psychiatry: Repurposing of its Fast-Acting Anxiolytic, Analgesic and Sleep Modulating Properties

Drug repurposing is a strategy to identify new indications for already approved drugs. A recent successful example in psychiatry is ketamine, an anesthetic drug developed in the 1960s, now approved and clinically used as a fast-acting antidepressant. Here, we describe the potential of dexmedetomidine as a psychopharmacological repurposing candidate. This α₂-adrenoceptor agonist is approved in the US and Europe for procedural sedation in intensive care. It has shown fast-acting inhibitory effects on perioperative stress-related pathologies, including psychomotor agitation, hyperalgesia, and neuroinflammatory overdrive, proving potentially useful in clinical psychiatry. We offer an overview of the pharmacological profile and effects of dexmedetomidine with potential utility for the treatment of neuropsychiatric symptoms. Dexmedetomidine exerts fast-acting and robust sedation, anxiolytic, analgesic, sleep-modulating, and anti-inflammatory effects. Moreover, the drug prevents postoperative agitation and delirium, possibly via neuroprotective mechanisms. While evidence in animals and humans supports these properties, larger controlled trials in clinical samples are generally scarce, and systematic studies with psychiatric patients do not exist. In conclusion, dexmedetomidine is a promising candidate for an experimental treatment targeting stress-related pathologies common in neuropsychiatric disorders such as depression, anxiety disorders, and posttraumatic stress disorder. First small proof-of-concept studies and then larger controlled clinical trials are warranted in psychiatric populations to test the feasibility and efficacy of dexmedetomidine in these conditions.

Clonidine Use for the Treatment of Nightmares in Posttraumatic Stress Disorder

Introduction

While clonidine is used clinically for the treatment of nightmares in posttraumatic stress disorder (PTSD), few case reports demonstrating this indication exist, and there have been few studies investigating clonidine's mechanism of action for controlling nightmare symptoms. Case Report. In order to further characterize clonidine's role in treating nightmare symptoms in PTSD, we offer this case report describing one United States veteran who presented to an inpatient psychiatric unit after a suicide attempt. At that time, she described a remote history of PTSD symptoms, including nightmares, flashbacks, hyperarousal, and avoidance behaviors which had been well controlled on sertraline and clonidine. Upon her admission, her home sertraline and alprazolam were continued but her home clonidine was not continued. On day two of her hospital stay, she stated that her nightmares had returned. Her home clonidine was restarted on day two. On day three and thereafter, the patient no longer complained of nightmares.

Conclusion

Our patient's nightmare symptoms had been controlled for years after beginning clonidine as an outpatient, but off clonidine, she had a return of her nightmare symptoms. Her nightmares again resolved once clonidine was resumed. Given this pattern in the patient's response to clonidine, this case may serve as additional evidence in the literature that clonidine has a role in treating nightmares in PTSD. Current proposed mechanisms of action for clonidine's ability to control nightmare symptoms in PTSD include that clonidine may alter the proportions of REM and non-REM sleep in a dose-dependent manner or that clonidine may play a role in memory consolidation. Further formal medication trials are the ideal future direction for establishing this role for clonidine.

Locus Coeruleus Acid-Sensing Ion Channels Modulate Sleep-Wakefulness and State Transition from NREM to REM Sleep in the Rat

The locus coeruleus (LC) is one of the essential chemoregulatory and sleep-wake (S-W) modulating centers in the brain. LC neurons remain highly active during wakefulness, and some implicitly become silent during rapid eye movement (REM) sleep. LC neurons are also involved in CO₂-dependent modulation of the respiratory drive. Acid-sensing ion channels (ASICs) are highly expressed in some brainstem chemosensory breathing regulatory areas, but their localization and functions in the LC remain unknown. Mild hypercapnia increases the amount of non-REM (NREM) sleep and the number of REM sleep episodes, but whether ASICs in the LC modulate S-W is unclear. Here, we investigated the presence of ASICs in the LC and their role in S-W modulation and the state transition from NREM to REM sleep. Male Wistar rats were surgically prepared for chronic polysomnographic recordings and drug microinjections into the LC. The presence of ASIC-2 and ASIC-3 in the LC was immunohistochemically characterized. Microinjections of amiloride (an ASIC blocker) and APETx2 (a blocker of ASIC-2 and -3) into the LC significantly decreased wakefulness and REM sleep, but significantly increased NREM sleep. Mild hypercapnia increased the amount of NREM and the number of REM episodes. However, APETx2 microinjection inhibited this increase in REM frequency. These results suggest that the ASICs of LC neurons modulate S-W, indicating that ASICs could play an important role in vigilance-state transition. A mild increase in CO₂ level during NREM sleep sensed by ASICs could be one of the determinants of state transition from NREM to REM sleep.

The Cognitive-Enhancing Effects of Dendrobium nobile Lindl Extract in Sleep Deprivation-Induced Amnesic Mice

Chronic sleep deprivation (SD) causes neurological and neurodegenerative dysfunction including learning and memory deficit. The orchid Dendrobium nobile Lindl (DNL), is widely used as a Yin tonic and medicinal food throughout Asia, and has many reported pharmacological effects. This study focused on the cognitive-enhancing effects of DNL in sleep deprivation-induced amnesia in mice and its biochemical mechanisms. Our results showed that the mice displayed significant cognitive deficits after 2-week SD while treatment with the extract of DNL prevented these impairments. In the novel object recognition and object location recognition tasks, a significant increase in the discrimination index was observed in DNL-treated (200 and 400 mg/kg) mice. In the MWM test, DNL (200 and 400 mg/kg) treatment shorten the prolongation of latency and increased the crossing numbers compared with SD mice. The biochemical analysis of brain tissue showed a decrease in NE, dismutase (T-SOD) and catalase (CAT) activity and an increase in 5-HT and malondialdehyde (MDA) concentration after the treatment with DNL in mice. Our findings indicated that DNL exerted a positive effect in preventing and improving cognitive impairment induced by SD, which may be mediated via the regulation of neurotransmitters and alleviation of oxidative stress.

Clinical Practice: Should we Radically Alter our Sedation of Critical Care Patients, Especially Given the COVID-19 Pandemics?

The high number of patients infected with the SARS-CoV-2 virus requiring care for ARDS puts sedation in the critical care unit (CCU) to the edge. Depth of sedation has evolved over the last 40 years (no-sedation, deep sedation, daily emergence, minimal sedation, etc.). Most guidelines now recommend determining the depth of sedation and minimizing the use of benzodiazepines and opioids. The broader use of alpha-2 adrenergic agonists ('alpha-2 agonists') led to sedation regimens beginning at admission to the CCU that contrast with hypnotics+opioids ("conventional" sedation), with major consequences for cognition, ventilation and circulatory performance. The same doses of alpha-2 agonists used for 'cooperative' sedation (ataraxia, analgognosia) elicit no respiratory depression but modify the autonomic nervous system (cardiac parasympathetic activation, attenuation of excessive cardiac and vasomotor sympathetic activity). Alpha-2 agonists should be selected only in patients who benefit from their effects ('personalized' indications, as opposed to a 'one size fits all' approach). Then, titration to effect is required, especially in the setting of systemic hypotension and/or hypovolemia. Since no general guidelines exist for the use of alpha-2 agonists for CCU sedation, our clinical experience is summarized for the benefit of physicians in clinical situations in which a recommendation might never exist (refractory delirium tremens; unstable, hypovolemic, hypotensive patients, etc.). Because the physiology of alpha-2 receptors and the pharmacology of alpha-2 agonists lead to personalized indications, some details are offered. Since interactions between conventional sedatives and alpha-2 agonists have received little attention, these interactions are addressed. Within the existing guidelines for CCU sedation, this article could facilitate the use of alpha-2 agonists as effective and safe sedation while awaiting large, multicentre trials and more evidence-based medicine.

Sleep and pain management: a review

There is a complex interplay between sleep disturbance and patients in pain. There is an increasing appreciation of the direct effects of analgesic drugs and sleep quality. This review provides an overview of the effects of different analgesic drugs and their effects on phases of sleep. The effects of different pain conditions and their direct effects on sleep physiology are also discussed. A structured search of the scientific literature using MEDLINE and PubMed databases. Original human and animal studies were included. A multi-search term strategy was employed. An appreciation of the physiological effects of these drugs will allow a more considered prescription of them to better manage sleep disturbance.

Managing sleep disturbances in children with atopic dermatitis

Atopic dermatitis is a chronic, pruritic inflammatory disease that often disrupts sleep in severely affected children, but there are limited studies to guide clinical management of these sleep problems. Disease control is crucial in improving sleep, but additional sleep aids may sometimes be helpful in decreasing scratching during the night. This review discusses the benefits and limitations of potential therapeutic agents available to manage sleep disturbances in children with atopic dermatitis.

Position Paper for the Treatment of Nightmare Disorder in Adults: An American Academy of Sleep Medicine Position Paper

INTRODUCTION

Nightmare disorder affects approximately 4% of adults, occurring in isolation or as part of other disorders such as posttraumatic stress disorder (PTSD), and can significantly impair quality of life. This paper provides the American Academy of Sleep Medicine (AASM) position regarding various treatments of nightmare disorder in adults.

METHODS

A literature search was performed based upon the keywords and MeSH terms from the Best Practice Guide for the Treatment of Nightmare Disorder in Adults that was published in 2010 by the AASM. The search used the date range March 2009 to August of 2017, and sought to find available evidence pertaining to the use of behavioral, psychological, and pharmacologic therapies for the treatment of nightmares. A task force developed position statements based on a thorough review of these studies and their clinical expertise. The AASM Board of Directors approved the final position statements.

DETERMINATION OF POSITION

Positions of "recommended" and "not recommended" indicate that a treatment option is determined to be clearly useful or ineffective/harmful for most patients, respectively, based on a qualitative assessment of the available evidence and clinical judgement of the task force. Positions of "may be used" indicate that the evidence or expert consensus is less clear, either in favor or against the use of a treatment option. The interventions listed below are in alphabetical order within the position statements rather than clinical preference: this is not meant to be instructive of the order in which interventions should be used.

POSITION STATEMENTS

The following therapy is recommended for the treatment of PTSD-associated nightmares and nightmare disorder: image rehearsal therapy. The following therapies may be used for the treatment of PTSD-associated nightmares: cognitive behavioral therapy; cognitive behavioral therapy for insomnia; eye movement desensitization and reprocessing; exposure, relaxation, and rescripting therapy; the atypical antipsychotics olanzapine, risperidone and aripiprazole; clonidine; cyproheptadine; fluvoxamine; gabapentin; nabilone; phenelzine; prazosin; topiramate; trazodone; and tricyclic antidepressants. The following therapies may be used for the treatment of nightmare disorder: cognitive behavioral therapy; exposure, relaxation, and rescripting therapy; hypnosis; lucid dreaming therapy; progressive deep muscle relaxation; sleep dynamic therapy; self-exposure therapy; systematic desensitization; testimony method; nitrazepam; prazosin; and triazolam. The following are not recommended for the treatment of nightmare disorder: clonazepam and venlafaxine. The ultimate judgment regarding propriety of any specific care must be made by the clinician, in light of the individual circumstances presented by the patient, accessible treatment options, and resources.

Hypothesis: Fever control, a niche for alpha-2 agonists in the setting of septic shock and severe acute respiratory distress syndrome?

During severe septic shock and/or severe acute respiratory distress syndrome (ARDS) patients present with a limited cardio-ventilatory reserve (low cardiac output and blood pressure, low mixed venous saturation, increased lactate, low PaO2/FiO2 ratio, etc.), especially when elderly patients or co-morbidities are considered. Rescue therapies (low dose steroids, adding vasopressin to noradrenaline, proning, almitrine, NO, extracorporeal membrane oxygenation, etc.) are complex. Fever, above 38.5-39.5°C, increases both the ventilatory (high respiratory drive: large tidal volume, high respiratory rate) and the metabolic (increased O2 consumption) demands, further limiting the cardio-ventilatory reserve. Some data (case reports, uncontrolled trial, small randomized prospective trials) suggest that control of elevated body temperature ("fever control") leading to normothermia (35.5-37°C) will lower both the ventilatory and metabolic demands: fever control should simplify critical care management when limited cardio-ventilatory reserve is at stake. Usually fever control is generated by a combination of general anesthesia ("analgo-sedation", light total intravenous anesthesia), antipyretics and cooling. However general anesthesia suppresses spontaneous ventilation, making the management more complex. At variance, alpha-2 agonists (clonidine, dexmedetomidine) administered immediately following tracheal intubation and controlled mandatory ventilation, with prior optimization of volemia and atrio-ventricular conduction, will reduce metabolic demand and facilitate normothermia. Furthermore, after a rigorous control of systemic acidosis, alpha-2 agonists will allow for accelerated emergence without delirium, early spontaneous ventilation, improved cardiac output and micro-circulation, lowered vasopressor requirements and inflammation. Rigorous prospective randomized trials are needed in subsets of patients with a high fever and spiraling toward refractory septic shock and/or presenting with severe ARDS.

Effect on Primary Sleep Disorders When Children With ADHD Are Administered Guanfacine Extended Release

OBJECTIVE

To evaluate children with ADHD and sleep problems with polysomnography (PSG) after guanfacine extended-release (GXR) administration.

METHOD

Double-blind, randomized, placebo-controlled study was terminated early due to treatment-emergent concerns after enrolling 29 children aged 6 to 12 years. After >4 weeks dose adjustment and >1 week dose stabilization, 11 children received GXR and 16 controls underwent analyses with PSG.

RESULTS

Although GXR improved ADHD symptoms, the primary outcome variable, total sleep time, was shorter in contrast to placebo (-57.32, SD = 89.17 vs. +31.32, SD = 59.54 min, p = .005). Increased time awake after sleep onset per hour of sleep was the primary factor for the reduction. Although rapid eye movement (REM), non-REM, and N3/slow wave sleep times were reduced, these were proportional to the overall sleep reduction. Sedation was common with GXR (73% vs. 6%).

CONCLUSION

Morning-administered GXR resulted in decreased sleep and may contribute to sedation.

Treatment of Post-Traumatic Stress Disorder Nightmares at a Veterans Affairs Medical Center

The effectiveness of medications for PTSD in general has been well studied, but the effectiveness of medicatio.ns prescribed specifically for post-traumatic stress disorder (PTSD) nightmares is less well known. This retrospective chart review examined the efficacy of various medications used in actual treatment of PTSD nightmares at one Veteran Affairs Hospital. Records at the Salem, VA Veterans Affairs Medical Center (VAMC) were examined from 2009 to 2013 to check for the efficacy of actual treatments used in comparis.on with treatments suggested in three main review articles. The final sample consisted of 327 patients and 478 separate medication trials involving 21 individual medications plus 13 different medication combinations. The three most frequently utilized medications were prazosin (107 trials), risperidone (81 trials), and quetiapine (72 trials). Five medications had 20 or more trials with successful results (partial to full nightmare cessation) in >50% of trials: risperidone (77%, 1.0–6.0 mg), clonidine (63%, 0.1–2.0 mg), quetiapine (50%, 12.5–800.0 mg), mirtazapine (50%; 7.5–30.0 mg), and terazosin (64%, 50.0–300.0 mg). Notably, olanzapine (2.5–10.0) was successful (full remission) in all five prescription trials in five separate patients. Based on the clinical results, the use of risperidone, clonidine, terazosin, and olanzapine warrants additional investigation in clinically controlled trials as medications prescribed specifically for PTSD nightmares.

Pediatric Sleep Pharmacology: A Primer

"What will you give my child to help him sleep?" is a common question parents ask and some health care providers abhor hearing. Entire families may suffer when one member does not sleep well. Poor sleep may complicate the management of other comorbid conditions. Health care providers may have received only limited education on sleep disorders and are frequently forced to choose between treatment options that are poorly studied in children. Fortunately, when addressed correctly, many children with chronic sleep disorders may improve their sleep and daytime behavior in a relatively short time. This review provides a framework to help understand the causes of poor sleep in children and the potential pharmacologic options.

Targeting modulation of noradrenalin release in the brain for amelioration of REMS loss-associated effects

Rapid eye movement sleep (REMS) loss affects most of the physiological processes, and it has been proposed that REMS maintains normal physiological processes. Changes in cultural, social, personal traits and life-style severely affect the amount and pattern of sleep, including REMS, which then manifests symptoms in animals, including humans. The effects may vary from simple fatigue and irritability to severe patho-physiological and behavioral deficits such as cognitive and behavioral dysfunctions. It has been a challenge to identify a molecule(s) that may have a potential for treating REMS loss-associated symptoms, which are very diverse. For decades, the critical role of locus coeruleus neurons in regulating REMS has been known, which has further been supported by the fact that the noradrenalin (NA) level is elevated in the brain after REMS loss. In this review, we have collected evidence from the published literature, including those from this laboratory, and argue that factors that affect REMS and vice versa modulate the level of a common molecule, the NA. Further, NA is known to affect the physiological processes affected by REMS loss. Therefore, we propose that modulation of the level of NA in the brain may be targeted for treating REMS loss-related symptoms. Further, we also argue that among the various ways to affect the release of NA-level, targeting α₂ adrenoceptor autoreceptor on the pre-synaptic terminal may be the better option for ameliorating REMS loss-associated symptoms.

[Dexmedetomidine and clonidine: a review of their pharmacodynamy to define their role for sedation in intensive care patients]

Alpha-2 adrenergic agonists ("alpha-2 agonists") present multiple pharmacodynamic effects: rousable sedation, decreased incidence of delirium in the setting of critical care, preservation of respiratory drive, decreased whole body oxygen consumption, decreased systemic and pulmonary arterial impedance, improved left ventricular systolic and diastolic function, preserved vascular reactivity to exogenous catecholamines, preserved vasomotor baroreflex with lowered set point, preserved kidney function, decreased protein catabolism. These pharmacodynamic effects explain the interest for these drugs in the critical care setting. However, their exact role for sedation in critically ill-patients remains open for further studies. Given the few double-blind randomized multicentric trials available, the present non exhaustive analysis of the literature aims at presenting the utilization of alpha-2 agonists as potential first-line sedative agents, in the critical care setting. Suggestions regarding the use of alpha-2 agonists as sedatives are detailed.

Dexmedetomidine and clonidine induce long-lasting activation of the respiratory rhythm generator of neonatal mice: possible implication for critical care

Dexmedetomidine and clonidine are alpha-2 adrenoceptor agonists increasingly used in the critical care unit as sedative agents for their benzodiazepine-sparing effects and their limited depressing effect on breathing. However adverse effects on breathing have been also reported with alpha-2 adrenoceptor agonists and their central effects on the respiratory rhythm generator are poorly known. We therefore examined the effects of dexmedetomidine, clonidine, the alpha-2 adrenoceptor antagonist yohimbine and the benzodiazepine midazolam on the activity of the isolated respiratory rhythm generator of neonatal mice using medullary preparations where the respiratory rhythm generator continued to function in vitro. For the first time, we showed that 5min bath applications of dexmedetomidine or clonidine activated the respiratory rhythm generator for periods over than 30min. Second, we showed that the long-lasting effect of dexmedetomidine implicated receptors other than alpha-2 adrenoceptors as it persisted after their blockade with yohimbine. Third, we reported that 5min bath applications of the benzodiazepine midazolam significantly depressed the respiratory rhythm generator, and that this depression was prevented by pre-treatment with either dexmedetomidine or clonidine. Although further experiments are still required to identify the mechanisms through which dexmedetomidine and clonidine activate the respiratory rhythm generator, our current in vitro results in neonatal mice support the use of dexmedetomidine and clonidine in the critical care unit.

Comorbidity and confounding factors in attention-deficit/hyperactivity disorder and sleep disorders in children

Sleep problems are commonly reported in children with attention-deficit/hyperactivity disorder (ADHD) symptoms. Research data regarding the complex and reciprocal relationship between ADHD and sleep disturbances has now accumulated. This paper is focused on the types of sleep problems that are associated with ADHD symptomatology, and attempts to untangle confounding factors and overlapping symptoms. The goal is also to present an updated overview of the pathophysiology of and treatment strategies for sleep problems in children with ADHD. The review also points out that future research will be needed to clarify further the other psychiatric comorbidities and side effects of medication in order to improve treatment outcomes and prevent misdiagnosis in clinical practice.

Evidence of a pharmacodynamic EEG profile in rats following clonidine administration using a nonlinear analysis

BACKGROUND

Changes caused by clonidine in rodent electroencephalograms (EEG) have been reported with some inconsistency. For this reason, a pre-clinical study was conducted in order to confirm previous findings with both a standard spectral analysis and a sleep stage scoring procedure. In addition, a nonlinear technique for analysing the time-varying signals was implemented to compare its performance against conventional approaches.

RESULTS

The nonlinear method succeeds in quantifying all dose-related responses from the data set relying solely on the EEG trace.

CONCLUSIONS

Nonlinear approaches can deliver a suitable alternative to the sleep-stage scoring methods commonly used for drug effect detection.

A framework for the assessment and treatment of sleep problems in children with attention-deficit/hyperactivity disorder

Children with attention-deficit/hyperactivity disorder (ADHD) have high rates of sleep problems and sleep disorders. It is critical that pediatricians assess for sleep problems during the course of ADHD assessment and when treating children with stimulant medication. Sleep must be considered in the differential diagnosis and in terms of comorbidity with ADHD. The most common sleep problem in children with ADHD is insomnia, and the first line of treatment should be the implementation of behavioral interventions rather than medication. More research is needed to determine if children with ADHD respond to behavioral interventions in a similar manner as typically developing children.

Clonidine has a paradoxical effect on cyclic arousal and sleep bruxism during NREM sleep

STUDY OBJECTIVE

Clonidine disrupts the NREM/REM sleep cycle and reduces the incidence of rhythmic masticatory muscle activity (RMMA) characteristic of sleep bruxism (SB). RMMA/SB is associated with brief and transient sleep arousals. This study investigates the effect of clonidine on the cyclic alternating pattern (CAP) in order to explore the role of cyclic arousal fluctuation in RMMA/SB.

DESIGN

Polysomnographic recordings from a pharmacological study.

SETTING

University sleep research laboratory.

PARTICIPANTS AND INTERVENTIONS

Sixteen SB subjects received a single dose of clonidine or placebo at bedtime in a crossover design.

MEASUREMENTS AND RESULTS

Sleep variables and RMMA/SB index were evaluated. CAP was scored to assess arousal instability between sleep-maintaining processes (phase A1) and stronger arousal processes (phases A2 and A3). Paired t-tests, ANOVAs, and cross-correlations were performed. Under clonidine, CAP time, and particularly the number of A3 phases, increased (P≤0.01). RMMA/SB onset was time correlated with phases A2 and A3 for both placebo and clonidine nights (P≤0.004). However, under clonidine, this positive correlation began up to 40 min before the RMMA/SB episode.

CONCLUSIONS

CAP phase A3 frequency increased under clonidine, but paradoxically, RMMA/SB decreased. RMMA/SB was associated with and facilitated in CAP phase A2 and A3 rhythms. However, SB generation could be influenced by other factors besides sleep arousal pressure. NREM/REM ultradian cyclic arousal fluctuations may be required for RMMA/SB onset.

Approaches to measuring the effects of wake-promoting drugs: a focus on cognitive function

OBJECTIVES

In clinical drug development, wakefulness and wake-promotion may be assessed by a large number of scales and questionnaires. Objective assessment of wakefulness is most commonly made using sleep latency/maintenance of wakefulness tests, polysomnography and/or behavioral measures. The purpose of the present review is to highlight the degree of overlap in the assessment of wakefulness and cognition, with consideration of assessment techniques and the underlying neurobiology of both concepts.

DESIGN

Reviews of four key areas were conducted: commonly used techniques in the assessment of wakefulness; neurobiology of sleep/wake and cognition; targets of wake promoting and/or cognition enhancing drugs; and ongoing clinical trials investigating wake promoting effects.

RESULTS

There is clear overlap between the assessment of wakefulness and cognition. There are common techniques which may be used to assess both concepts; aspects of the neurobiology of both concepts may be closely related; and wake-promoting drugs may have nootropic properties (and vice versa). Clinical trials of wake-promoting drugs often, though not routinely, assess aspects of cognition.

CONCLUSIONS

Routine and broad assessment of cognition in the development of wake-promoting drugs may reveal important nootropic effects, which are not secondary to alertness/wakefulness, whilst existing cognitive enhancers may have underexplored or unknown wake promoting properties.

[Sleep disturbances in critically ill patients]

Sleep is an essential part of life with many important roles which include immunologic, cognitive and muscular functions. Of the working population 20% report sleep disturbances and in critically ill patients an incidence of more than 50% has been shown. However, sleep disturbances in the intensive care unit (ICU) population have not been investigated in detail. Sleep disturbances in ICU patients have a variety of reasons: e.g. patient-related pathologies like sepsis, acute or chronic pulmonary diseases, cardiac insufficiency, stroke or epilepsy, surgery, therapeutical interventions like mechanical ventilation, noise of monitors, pain or medication. Numerous scales and questionnaires are used to quantify sleep and the polysomnogramm is used to objectify sleep architecture. To improve sleep in ICU patients concepts are needed which include in addition to pharmacological treatment (pain reduction and sedation) synchronization of ICU activities with daylight, noise reduction and music for relaxation. In order to establish evidence-based guidelines, research activities about sleep and critical illness should be intensified. Questions to be answered are: 1) Which part of sleep disturbances in critically ill patients is directly related to the illness or trauma? 2) Is the grade of sleep disturbance correlated with the severity of the illness or trauma? 3) Which part is related to the medical treatment and can be modified or controlled? In order to define non-pharmacological and pharmacological concepts to improve sleep quality, studies need to be randomized and to include different ICU populations. The rate of nosocomial infections, cognitive function and respiratory muscle function should be considered in these studies as well. This will help to answer the question, whether it is useful to monitor sleep in ICU patients as a parameter to indicate therapeutical success and short-term quality of life. Follow-up needs to be long enough to detect adverse effects of withdrawal symptoms after termination of analgesia and sedation or delirium.

Pharmacologic reduction of CNS noradrenergic activity in PTSD: the case for clonidine and prazosin

This article reviews the neurobiologic rationale for and presents clinical guidance concerning the use of medications that reduce central nervous system noradrenergic activity in the treatment of intrusive symptoms of posttraumatic stress disorder. The authors reviewed neurobiological studies, nonclinical studies using animal models, clinical case reports, open-label drug studies, and blinded, placebo-controlled drug studies. This review of the basic science and clinical literature, and the authors' clinical experience with culturally and demographically diverse populations, indicate that clonidine and prazosin can play a useful role in treating sleep disturbance and hyperarousal in posttraumatic stress disorder, with minimal adverse effects and low financial cost.

Clonidine and modification of perioperative outcome

PURPOSE OF REVIEW

Perioperative cardiac risk reduction using perioperative beta-blockade is being widely adopted. Recent research has identified a second-line agent, perioperative clonidine, that can be used to reduce the risk of perioperative cardiac mortality. Perioperative clonidine has some advantages over perioperative beta-blockers because it has less risk of bronchospasm in asthmatics and it comes in a transcutaneous form that can be used in patients who are not taking oral medications ('NPO').

RECENT FINDINGS

Clonidine has been used for many purposes, including reduction of blood pressure in hypertension, reduction in alcohol and drug withdrawal phenomena, reduction in nicotine withdrawal symptoms during smoking cessation, analgesia, reduction in stress response, and now as an anti-ischemic agent to reduce the risk of perioperative myocardial ischemia and perioperative mortality.

SUMMARY

Administration of perioperative clonidine can reduce the risk of perioperative myocardial ischemia and mortality in patients undergoing non-cardiac surgery. Perioperative clonidine comes in a patch form that can be used in patients who are not taking medications by mouth, and can be used when beta-blockers are contraindicated (for asthmatics or patients with high-grade atrioventricular block).

Pharmacotherapy for disordered sleep in post-traumatic stress disorder: a systematic review

Sleep disorders, such as insomnia and nightmares, are common problems in post-traumatic stress disorder (PTSD), exert a strong negative influence on the quality of life and are a great challenge for clinical psychiatry. Several studies have reported on the efficacy of drugs for the treatment of PTSD-related sleep disorders. These studies have not been systematically reviewed. This is the first review on the effectiveness of sleep medication in PTSD. We performed a Medline, EMBASE and Cochrane Library Indexed search, using the keywords: PTSD, pharmacotherapy, therapy, sleep, nightmares, insomnia and review. From this database, English-language, human subject, data driven papers published after 1980 were selected. Forty eight articles are discussed. Open-label and case studies suggest efficacy for some antidepressants, anticonvulsants and atypical antipsychotics. Only a few placebo-controlled studies have been published. They show promising results for the atypical antipsychotic olanzapine, and the alpha1-adrenoceptor antagonist prazosin. In comparison to the incidence and impact of sleep complaints in PTSD, the pharmacotherapeutic armamentarium for PTSD-related sleep complaints remains poorly investigated. Some recent studies show promising results, especially for alpha1-adrenoceptor and 5-HT2 receptor antagonists. However, randomized controlled trials with larger populations need to be conducted.

Attention deficit hyperactivity disorder, tics and Tourette's syndrome: the relationship and treatment implications. A commentary

Tourette's Syndrome (TS) is now recognised to be a common childhood onset neurodevelopmental disorder. Attention deficit hyperactivity disorder (ADHD) is also a common childhood disorder. There are many cases in which the two disorders are comorbid. The reasons for this are unclear, but the comorbidity does not necessarily point to one genetic cause. Sleep is also often disturbed in individuals with TS and ADHD. The treatment implications of ADHD in the setting of tics or TS are important. Clonidine is suggested as a first line treatment. It was once thought that stimulants were contraindicated in the treatment of ADHD in the setting of TS, whereas it is suggested that they may be safe, but should be used judiciously. In addition, it was once thought that the combination of stimulants and clonidine was contraindicated, but from a large study the combination does appear to be safe. A relatively new medication for ADHD is atomoxetine, and although not documented widely in the setting of tics and TS, it may prove useful in this setting; further research is required. This commentary briefly discusses the comorbidity between TS and ADHD and offers treatment suggestions.