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Insomnia is a common sleep disorder that is closely associated with the occurrence and deterioration of cardiovascular disease, depression and other diseases. The evaluation of pharmacological treatments for insomnia brings significant clinical implications. In this study, a total of 20 patients with mild insomnia and 75 healthy subjects as controls (HC) were included to explore alterations of electroencephalogram (EEG) complexity associated with insomnia and its pharmacological treatment by using multi-scale permutation entropy (MPE). All participants were recorded for two nights of polysomnography (PSG). The patients with mild insomnia received a placebo on the first night (Placebo) and temazepam on the second night (Temazepam), while the HCs had no sleep-related medication intake for either night. EEG recordings from each night were extracted and analyzed using MPE. The results showed that MPE decreased significantly from pre-lights-off to the period during sleep transition and then to the period after sleep onset, and also during the deepening of sleep stage in the HC group. Furthermore, results from the insomnia subjects showed that MPE values were significantly lower for the Temazepam night compared to MPE values for the Placebo night. Moreover, MPE values for the Temazepam night showed no correlation with age or gender. Our results indicated that EEG complexity, measured by MPE, may be utilized as an alternative approach to measure the impact of sleep medication on brain dynamics.
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OBJECTIVE: Benzodiazepines impair driving ability and psychomotor function. Eyelid parameters accurately reflect drowsiness; however, the effects of benzodiazepines on these measures have not been extensively studied. The aim of this study was to investigate the effect of benzodiazepines on eyelid parameters and evaluate their accuracy for detecting psychomotor impairment. METHODS: Eyelid parameters were recorded during a psychomotor vigilance task (PVT) and driving simulation over 2 days, baseline, and after 20-mg oral temazepam. The utility of eyelid parameters for detecting PVT lapses was evaluated using receiver operating characteristic curves, and cut-off levels indicating impairment (≥1 and ≥2 PVT lapses per min) were identified. The accuracy of these cut-off levels for detecting driving simulator crashes was then examined. RESULTS: PVT and driving simulator performance was significantly impaired following benzodiazepine administration (p < .05). Average eyelid closure duration (inter-event duration) was a reliable indicator of PVT lapses (area under the curve [AUC] of 0.87-0.90). The cut-off value of eyelid closure duration derived from PVT AUC was able to predict driving simulator crashes with moderately high sensitivity and specificity (76.23% and 75.00%). CONCLUSIONS: Eyelid parameters were affected by benzodiazepines and accurately detected the psychomotor impairment. In particular, eyelid closure duration is a promising real-time indicator of benzodiazepine impairment.
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Benzodiazepinas/efeitos adversos , Pálpebras/fisiopatologia , Transtornos Psicomotores/diagnóstico , Adolescente , Adulto , Idoso , Condução de Veículo , Simulação por Computador , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Psicomotores/induzido quimicamente , Desempenho Psicomotor/fisiologia , Adulto JovemRESUMO
The abuse of benzodiazepine (BZP) and Z drugs has become, due to the tolerance and dependence they produce, a serious public health problem. Thirty years ago, we demonstrated in experimental animals the interaction of melatonin with central BZD receptors, and in 1997 we published the first series of elderly patients who reduced BZP consumption after melatonin treatment. Almost every single neuron in the hypothalamic suprachiasmatic nuclei (SCN), the central pacemaker of the circadian system, contains γ-aminobutyric acid (GABA) and many results in animals point out to a melatonin interaction with GABA-containing neurons. In addition, central-type BZD antagonism, that obliterates GABAA receptor function, blunted most behavioral effects of melatonin including sleep. Melatonin is involved in the regulation of human sleep. This is supported by the temporal relationship between the rise of plasma melatonin levels and sleep propensity as well as by the sleep-promoting effects of exogenously administered melatonin. Both meta-analyses and consensus agreements give support to the therapeutic use of melatonin in sleep disorders. This action is attributed to MT1 and MT2 melatoninergic receptors localized in the SCN, as well as in other brain areas. This review discusses available data on the efficacy of melatonin to curtail chronic BZD/Z drug use in insomnia patients. A major advantage is that melatonin has a very safe profile, it is usually remarkably well tolerated and, in some studies, it has been administered to patients at very large doses and for long periods of time, without any potentiality of abuse. Further studies on this application of melatonin are warranted.
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Benzodiazepinas , Melatonina/uso terapêutico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Transtornos Relacionados ao Uso de Substâncias/prevenção & controle , Animais , Benzodiazepinas/uso terapêutico , Neurônios GABAérgicos/fisiologia , Humanos , Melatonina/fisiologiaRESUMO
AIM: We compared the efficacy of melatonin and placebo as adjuvants in the withdrawal of patients from long term temazepam, zopiclone or zolpidem (here 'BZD') use. METHODS: A double-blind, placebo-controlled, randomized trial was conducted in a primary health care outpatient clinic. Ninety-two men or women (≥55 years) with primary insomnia and chronic BZD use received controlled release melatonin 2 mg (CRM) (n = 46) or placebo (n = 46) during the 1 month withdrawal from BZDs. Psychosocial support was provided. Follow-up continued for up to 6 months. Successful BZD withdrawal by the end of 1 month was confirmed by BZD plasma determinations, while reduction in BZD use and abstinence continuing for 6 months were noted. RESULTS: There were two drop-outs on CRM and one on placebo. After a 1 month withdrawal, 31 participants (67%; 95% CI 54, 81) on CRM and 39 (85%; 74, 95) on placebo had withdrawn completely (intention-to-treat analysis between groups, P = 0.051; per protocol P = 0.043). Reduction in BZD use was similar or even more rare in the CRM than in the placebo group (P = 0.052 per protocol). After 6 months, 14 participants in the CRM group and 20 in the placebo group remained non-users of BZD (NS between groups). BZD doses were higher in the CRM than in the placebo group at the end of the 6 month follow-up (P = 0.025). Withdrawal symptoms did not differ between the groups. CONCLUSIONS: Gradual dose reduction of BZDs combined with CRM or placebo, and psychosocial support produced high short term and moderate long term BZD abstinence. CRM showed no withdrawal benefit compared with placebo.
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Hipnóticos e Sedativos/uso terapêutico , Melatonina/uso terapêutico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Síndrome de Abstinência a Substâncias/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Método Duplo-Cego , Feminino , Humanos , Hipnóticos e Sedativos/efeitos adversos , Masculino , Melatonina/efeitos adversos , Pessoa de Meia-IdadeRESUMO
In a recent survey of 16,694 people receiving treatment for Restless Legs Syndrome (RLS), approximately 25% were treated with benzodiazepines either singly or in combination with other RLS treatments. Because of the large number of people receiving benzodiazepines for treatment of RLS, we conducted a historical overview of the therapeutic role of benzodiazepines in RLS and its associated condition Periodic Limb Movements in Sleep (PLMS). We found 17 articles on the use of clonazepam in RLS, PLMS, or both, 3 on triazolam and PLMS, 1 on alprazolam and RLS, 1 on temazepam and PLMS, and 1 on nitrazepam and PLMS. The order of benefit of benzodiazepines from the summarized literature is Sleep>RLS>PLMS and arousals > PLMS. Most of the studies on clonazepam employed dosages of 0.5-2.0 mg. Dosages of 3 or 4 mg caused lethargy, somnolence and confusion. An epidemiological study on the therapy of RLS suggests that treatment of RLS with most types of RLS medications including benzodiazepines in combination with other RLS therapies lowers the future cardiovascular risk associated with RLS. The major effect of benzodiazepines is through potentiation of the effect of GABA on the GABA A receptor. Neuroimaging studies suggest that GABA is altered either positively or negatively in various brain regions in RLS and genetic studies suggest that there are alterations in the GABA receptor in RLS. These results suggest that medications with different GABAergic mechanisms such as tiagabine (Gabitril) or others should be investigated in RLS for their possible therapeutic benefit. Highlights: Benzodiazepines are frequently used as therapy in Restless Legs Syndrome (RLS) and Periodic Limb Movements in Sleep. The order of benefit is Sleep>RLS>PLMS and arousals > PLMS. For clonazepam dosages of 0.5 mg-2.0 mg/day are most frequently employed. Benzodiazepines exert their therapeutic effect through GABA-ergic mechanisms.
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Benzodiazepinas , Clonazepam , Síndrome da Mioclonia Noturna , Síndrome das Pernas Inquietas , Síndrome das Pernas Inquietas/tratamento farmacológico , Humanos , Clonazepam/uso terapêutico , Benzodiazepinas/uso terapêutico , Síndrome da Mioclonia Noturna/tratamento farmacológico , História do Século XX , História do Século XXI , AdultoRESUMO
Background: Sleep disturbance has a prevalence of 30-78% in patients with advanced cancer. While pharmacotherapy is common, randomized controlled studies (RCTs) investigating available agents are limited. This study examines the efficacy and safety of temazepam or melatonin versus placebo for sleep in advanced cancer. Methods: This is a multicenter, randomized, double-blind, placebo-controlled study of temazepam, melatonin prolonged release (PR) or placebo for insomnia in patients with advanced cancer, and an insomnia severity index (ISI) score of >11. Results: Twenty-one participants were randomized: nine to temazepam, eight to melatonin, and four to placebo. Baseline characteristics between groups were similar. The adjusted mean difference in day 8 ISI score versus placebo was -9.1 (95% confidence interval [CI] -17.5, 0.7, p = 0.04) for temazepam and -9.6 (95% CI -18,-1.2, p = 0.03) for melatonin PR. There was no improvement in global quality of life. Both agents were well tolerated. Conclusion: Temazepam and melatonin PR were associated with a clinically significant improvement in patient-reported insomnia severity compared with placebo. Findings need confirmation with larger patient numbers.
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Melatonina , Neoplasias , Distúrbios do Início e da Manutenção do Sono , Temazepam , Humanos , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Masculino , Método Duplo-Cego , Feminino , Melatonina/uso terapêutico , Melatonina/administração & dosagem , Pessoa de Meia-Idade , Idoso , Neoplasias/complicações , Neoplasias/tratamento farmacológico , Temazepam/uso terapêutico , Temazepam/administração & dosagem , Adulto , Hipnóticos e Sedativos/uso terapêutico , Hipnóticos e Sedativos/administração & dosagem , Placebos , Resultado do Tratamento , Qualidade de Vida , Idoso de 80 Anos ou maisRESUMO
Pharmaceutically active compounds (PhACs) have been shown to accumulate in aquatic and riparian food-webs. Yet, our understanding of how temperature, a key environmental factor in nature, affects uptake, biotransformation, and the subsequent accumulation of PhACs in aquatic organisms is limited. In this study, we tested to what extent bioconcentration of an anxiolytic drugs (temazepam and oxazepam) is affected by two temperature regimes (10 and 20 °C) and how the temperature affects the temazepam biotransformation and subsequent accumulation of its metabolite (oxazepam) in aquatic organisms. We used European perch (Perca fluviatilis) and dragonfly larvae (Sympetrum sp.), which represent predator and prey species of high ecological relevance in food chains of boreal and temperate aquatic ecosystems. Experimental organisms were exposed to target pharmaceuticals at a range of concentrations (0.2-6 µg L-1) to study concentration dependent differences in bioconcentration and biotransformation. We found that the bioconcentration of temazepam in perch was significantly reduced at higher temperatures. Also, temperature had a strong effect on temazepam biotransformation in the fish, with the production and subsequent accumulation of its metabolite (oxazepam) being two-fold higher at 20 °C compared to 10 °C. In contrast, we found no temperature dependency for temazepam bioconcentration in dragonfly larvae and no detectable biotransformation of the parent compound that would result in measurable concentrations of oxazepam in this organism. Our results highlight that while organisms may share the same aquatic ecosystem, their exposure to PhACs may change differently across temperature gradients in the environment.
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Odonatos , Percas , Preparações Farmacêuticas , Poluentes Químicos da Água , Animais , Organismos Aquáticos , Biotransformação , Ecossistema , Temperatura , ÁguaRESUMO
Fatigue poses an important safety risk to civil and military aviation. In addition to decreasing performance in-flight (chronic) fatigue has negative long-term health effects. Possible causes of fatigue include sleep loss, extended time awake, circadian phase irregularities and work load. Despite regulations limiting flight time and enabling optimal rostering, fatigue cannot be prevented completely. Especially in military operations, where limits may be extended due to operational necessities, it is impossible to rely solely on regulations to prevent fatigue. Fatigue management, consisting of preventive strategies and operational countermeasures, such as pre-flight naps and pharmaceuticals that either promote adequate sleep (hypnotics or chronobiotics) or enhance performance (stimulants), may be required to mitigate fatigue in challenging (military) aviation operations. This review describes the pathophysiology, epidemiology and effects of fatigue and its impact on aviation, as well as several aspects of fatigue management and recommendations for future research in this field.
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INTRODUCTION: Hospitalised older patients frequently suffer from inadequate sleep, which can lead to patient distress and delayed recovery from acute illness or surgical procedure. Currently, no evidence-based treatments exist for sleeping problems in hospitalised older patients. Benzodiazepines, such as temazepam, are regularly prescribed by physicians, although they have serious side effects; for older patients in particular. Melatonin is proposed as a safe alternative for sleeping problems in hospitalised older patients, but the efficacy of melatonin is unclear in this population. Therefore, the aim of this study is to investigate the effects of melatonin and temazepam compared with placebo on sleep quality among hospitalised older patients with sleeping problems. METHODS AND ANALYSIS: This study is a multicentre, randomised, placebo-controlled trial. A total of 663 patients will be randomised in a 1:1:1 fashion to receive either melatonin (n=221), temazepam (n=221) or placebo (n=221). The study population consists of hospitalised patients aged 60 years and older, with new or aggravated sleeping problems for which an intervention is needed. The primary outcome is sleep quality measured with the Leeds Sleep Evaluation Questionnaire (LSEQ). Secondary outcomes include sleep parameters measured with actigraphy and medication-related adverse effects. ETHICS AND DISSEMINATION: This study was approved by the Medical Ethics Committee of the Academic Medical Centre Amsterdam, (No 2015_302). Study findings will be disseminated through presentations at professional and scientific conferences and publications in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NTR6908; Pre-results.
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Preparações de Ação Retardada/uso terapêutico , Geriatria , Hipnóticos e Sedativos/uso terapêutico , Melatonina/uso terapêutico , Transtornos do Sono-Vigília/tratamento farmacológico , Temazepam/uso terapêutico , Idoso , Nível de Alerta/efeitos dos fármacos , Preparações de Ação Retardada/farmacologia , Hospitalização , Humanos , Hipnóticos e Sedativos/farmacologia , Melatonina/farmacologia , Pessoa de Meia-Idade , Placebos , Ensaios Clínicos Controlados Aleatórios como Assunto , Sono/efeitos dos fármacos , Temazepam/farmacologia , Resultado do TratamentoRESUMO
Pharmaceuticals as environmental contaminants have received a lot of interest over the past decade but, for several pharmaceuticals, relatively little is known about their occurrence in European surface waters. Benzodiazepines, a class of pharmaceuticals with anxiolytic properties, have received interest due to their behavioral modifying effect on exposed biota. In this study, our results show the presence of one or more benzodiazepine(s) in 86% of the analyzed surface water samples (n = 138) from 30 rivers, representing seven larger European catchments. Of the 13 benzodiazepines included in the study, we detected 9, which together showed median and mean concentrations (of the results above limit of quantification) of 5.4 and 9.6 ng L-1, respectively. Four benzodiazepines (oxazepam, temazepam, clobazam, and bromazepam) were the most commonly detected. In particular, oxazepam had the highest frequency of detection (85%) and a maximum concentration of 61 ng L-1. Temazepam and clobazam were found in 26% (maximum concentration of 39 ng L-1) and 14% (maximum concentration of 11 ng L-1) of the samples analyzed, respectively. Finally, bromazepam was found only in Germany and in 16 out of total 138 samples (12%), with a maximum concentration of 320 ng L-1. This study clearly shows that benzodiazepines are common micro-contaminants of the largest European river systems at ng L-1 levels. Although these concentrations are more than a magnitude lower than those reported to have effective effects on exposed biota, environmental effects cannot be excluded considering the possibility of additive and sub-lethal effects.
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Benzodiazepinas/análise , Monitoramento Ambiental/métodos , Rios/química , Poluentes Químicos da Água/análise , Clobazam , Europa (Continente) , Oxazepam/análise , Temazepam/análiseRESUMO
GABAA receptor positive allosteric modulators (GABAA receptor modulators) are commonly used for the treatment of insomnia. Nevertheless, the effects of these compounds on psychostimulant-induced sleep impairment are poorly understood. Because GABAA receptor modulators have been shown to decrease the abuse-related effects of psychostimulants, the aim of the present study was to evaluate the effects of temazepam (0.3, 1.0 or 3.0 mg/kg) and eszopiclone (0.3, 1.0 or 3.0 mg/kg), two GABAA receptor modulators, on the behavioral neuropharmacology of methamphetamine in adult rhesus macaques (n = 5). Sleep-like measures and general daytime activity were evaluated with Actiwatch monitors. Methamphetamine self-administration (0.03 mg/kg/inf) was evaluated during morning sessions. Methamphetamine-induced dopamine overflow was assessed through in vivo microdialysis targeting the nucleus accumbens. Nighttime treatment with either temazepam or eszopiclone was ineffective in improving sleep-like measures disrupted by methamphetamine self-administration. Acute pretreatment with a low dose of temazepam before self-administration sessions increased methamphetamine self-administration without affecting normal daytime home-cage activity. At a high dose, acute temazepam pretreatment decreased methamphetamine self-administration and attenuated methamphetamine-induced increases in dopamine in the nucleus accumbens, without decreasing general daytime activity. Acute eszopiclone treatment exerted no effects on methamphetamine intake or drug-induced increases in dopamine. Our study suggests that treatments based on GABAA receptor modulators are not effective for the treatment of sleep disruption in the context of psychostimulant use. In addition, distinct GABAA receptor modulators differentially modulated the abuse-related effects of methamphetamine, with acute treatment with the high efficacy GABAA receptor modulator temazepam decreasing the behavioral and neurochemical effects of methamphetamine.
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Transtornos Relacionados ao Uso de Anfetaminas/tratamento farmacológico , Dopamina/metabolismo , Zopiclona/farmacologia , Agonistas de Receptores de GABA-A/farmacologia , Sono/efeitos dos fármacos , Temazepam/farmacologia , Transtornos Relacionados ao Uso de Anfetaminas/metabolismo , Animais , Estimulantes do Sistema Nervoso Central/administração & dosagem , Relação Dose-Resposta a Droga , Feminino , Macaca mulatta , Masculino , Metanfetamina/administração & dosagem , Receptores de GABA-A/metabolismo , AutoadministraçãoRESUMO
BACKGROUND: Dispensing patterns reflect drug usage trends. Benzodiazepines are known as drugs with potential for misuse, and frequent dispensing may be a surrogate marker of misuse. OBJECTIVE: The primary aim of this study was to obtain a comparative snapshot of anxiolytic and sedative-hypnotic dispensing in a developing country and a developed country, to determine whether further research about benzodiazepines is warranted. METHOD: A cross-national, cross-sectional retrospective drug utilisation study was conducted on benzodiazepines and z-drugs. The South African database was obtained from a national medical insurance administrator and the Australian data were de-identified and extracted from pharmacies in the city of Brisbane in Queensland. RESULTS: Diazepam was the most frequently dispensed anxiolytic in the Australian dataset (26.4%; n=1057/4010) while in the South African data, diazepam dispensing (17.2%; n=11597/67354) was superseded by alprazolam (17.8%; n=12009/67354) and followed by bromazepam (13.6%; n=9146/67354). The most frequently dispensed hypnotic in the South African data was zolpidem which accounted for 18.7% of records (n=12603/67354), while in the Australian data it was temazepam (24.9%; n=998/4010). Zolpidem was dispensed more frequently than zopiclone in both datasets. CONCLUSION: In South Africa there was relatively frequent use of alprazolam, bromazepam and zolpidem while in the Australian data diazepam, oxazepam and temazepam were most frequently dispensed. The use of alprazolam, identified as a drug of abuse in Australia, warrants further research in South Africa. The indicator described in this paper permitted a (qualitative) cross-sectional comparison of anxiolytics and sedative-hypnotics between a developed and a developing country (Australia and South Africa).
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Ansiolíticos/uso terapêutico , Bases de Dados Factuais/tendências , Países em Desenvolvimento , Prescrições de Medicamentos , Uso de Medicamentos/tendências , Hipnóticos e Sedativos/uso terapêutico , Austrália/epidemiologia , Estudos Transversais , Estudos de Viabilidade , Humanos , Estudos Retrospectivos , África do Sul/epidemiologiaRESUMO
Slow waves are characteristic waveforms that occur during non-rapid eye movement (NREM) sleep that play an integral role in sleep quality and brain plasticity. Benzodiazepines are commonly used medications that alter slow waves, however, their effects may depend on the time of night and measure used to characterize slow waves. Prior investigations have utilized minimal scalp derivations to evaluate the effects of benzodiazepines on slow waves, and thus the topography of changes to slow waves induced by benzodiazepines has yet to be fully elucidated. This study used high-density electroencephalography (hdEEG) to evaluate the effects of oral temazepam on slow wave activity, incidence, and morphology during NREM sleep in 18 healthy adults relative to placebo. Temazepam was associated with significant decreases in slow wave activity and incidence, which were most prominent in the latter portions of the sleep period. However, temazepam was also associated with a decrease in the magnitude of high-amplitude slow waves and their slopes in the first NREM sleep episode, which was most prominent in frontal derivations. These findings suggest that benzodiazepines produce changes in slow waves throughout the night that vary depending on cortical topography and measures used to characterize slow waves. Further research that explores the relationships between benzodiazepine-induced changes to slow waves and the functional effects of these waveforms is indicated.
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Encéfalo/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Hipnóticos e Sedativos/administração & dosagem , Sono/efeitos dos fármacos , Temazepam/administração & dosagem , Administração Oral , Adolescente , Adulto , Encéfalo/fisiologia , Feminino , Humanos , Masculino , Sono/fisiologia , Adulto JovemRESUMO
Benzodiazepines are commonly used medications that alter sleep spindles during non-rapid eye movement (NREM) sleep, however the topographic changes to these functionally significant waveforms have yet to be fully elucidated. This study utilized high-density electroencephalography (hdEEG) to investigate topographic changes in sleep spindles and spindle-range activity caused by temazepam during NREM sleep in 18 healthy adults. After an accommodation night, sleep for all participants was recorded on two separate nights after taking either placebo or oral temazepam 15 mg. Sleep was monitored using 256-channel hdEEG. Spectral analysis and spindle waveform detection of sleep EEG data were performed for each participant night. Global and topographic data were subsequently compared between temazepam and placebo conditions. Temazepam was associated with significant increases in spectral power from 10.33 to 13.83 Hz. Within this frequency band, temazepam broadly increased sleep spindle duration, and topographically increased spindle amplitude and density in frontal and central-posterior regions, respectively. Higher frequency sleep spindles demonstrated increased spindle amplitude and a paradoxical decrease in spindle density in frontal and centroparietal regions. Further analysis demonstrated temazepam both slowed the average frequency of spindle waveforms and increased the relative proportion of spindles at peak frequencies in frontal and centroparietal regions. These findings suggest that benzodiazepines have diverse effects on sleep spindles that vary by frequency and cortical topography. Further research that explores the relationships between topographic and frequency-dependent changes in pharmacologically-induced sleep spindles and the functional effects of these waveforms is indicated.
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Encéfalo/efeitos dos fármacos , Encéfalo/fisiologia , Hipnóticos e Sedativos/administração & dosagem , Fases do Sono/efeitos dos fármacos , Fases do Sono/fisiologia , Temazepam/administração & dosagem , Administração Oral , Adolescente , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Polissonografia , Adulto JovemRESUMO
Current pharmacological treatments for insomnia include benzodiazepine and non-benzodiazepine hypnotics targeting γ-aminobutyric acid (GABA)A receptors, as well as agonists of the melatonin receptors MT1 and MT2. Melatonin, temazepam and zolpidem are thought to exert their effect through different mechanisms of action, but whether this leads to differential effects on electroencephalogram (EEG) power spectra during sleep in middle-aged people is currently not known. To establish whether the effects of prolonged-release melatonin (2 mg) on the nocturnal sleep EEG are different to those of temazepam (20 mg) and zolpidem (10 mg). Sixteen healthy men and women aged 55-64 years participated in a double-blind, placebo-controlled, four-way cross-over trial. Nocturnal sleep was assessed with polysomnography and spectral analysis of the EEG. The effects of single oral doses of prolonged-release melatonin, temazepam and zolpidem on EEG slow-wave activity (SWA, 0.75-4.5 Hz) and other frequencies during nocturnal non-rapid eye movement (NREM) sleep were compared. In an entire night analysis prolonged-release melatonin did not affect SWA, whereas temazepam and zolpidem significantly reduced SWA compared with placebo. Temazepam significantly reduced SWA compared with prolonged-release melatonin. Prolonged-release melatonin only reduced SWA during the first third of the night compared with placebo. These data show that the effects of prolonged-release melatonin on the nocturnal sleep EEG are minor and are different from those of temazepam and zolpidem; this is likely due to the different mechanisms of action of the medications.