Zolpidem: a review of its use in the management of insomnia

Imidazo[1,2-a]pyridines susceptible to excited state intramolecular proton transfer: one-pot synthesis via an Ortoleva-King reaction

A short and efficient route to a broad range of imidazo[1,2-a]pyridines from 2-aminopyridines and acetophenones is achieved by a tandem, one-pot process starting with an Ortoleva-King reaction. Optimal conditions for the first step were established after examining various reaction parameters (solvent, reagent ratios, and temperature). The conditions identified (1st step, neat, 2.3 equiv of 2-aminopyridine, 1.20 equiv of I(2), 4 h, 110 °C; 2nd step, NaOH(aq), 1 h, 100 °C) resulted in the formation of imidazo[1,2-a]pyridines in 40-60% yields. The synthesis is compatible with various functionalities (OH, NMe(2), Br, OMe). Products containing a 2-(2'-hydroxyphenyl) substituent undergo excited state intramolecular proton transfer (ESIPT) in nonpolar and polar-aprotic solvents. Although ESIPT-type emission in nonpolar solvents is weak, the Stokes shifts are very high (11000 cm(-1)). The comparison of the properties of six ESIPT-capable imidazo[1,2-a]pyridines shows the influence of various substituents on emission characteristics. All of them also display strong, solid-state emission in blue-green-yellow region. 2-Aryl-imidazo[1,2-a]pyridines not capable of ESIPT emit in the blue region, displaying high fluorescence quantum yield.

CuSO4-glucose for in situ generation of controlled Cu(I)-Cu(II) bicatalysts: multicomponent reaction of heterocyclic azine and aldehyde with alkyne, and cycloisomerization toward synthesis of N-fused imidazoles

The catalytic efficiency of mixed Cu(I)-Cu(II) system in situ generated by partial reduction of CuSO(4) with glucose in ethanol (nonanhydrous) under open air has been explored. With this catalysis, the multicomponent cascade reaction of A(3)-coupling of heterocyclic amidine with aldehyde and alkyne, 5-exo-dig cycloisomerization, and prototropic shift has afforded an efficient and eco-friendly synthesis of therapeutically important versatile N-fused imidazoles. Diverse heterocyclic amidines, several of which are known to be poorly reactive, and aldehydes are compatible in this catalytic process.

Zolpidem for insomnia

INTRODUCTION

The imidazopyridine derivative zolpidem , which acts as a benzodiazepine (BZ) receptor agonist, is the most widely prescribed hypnotic drug in the US.

AREAS COVERED

This review addresses the neuroreceptor properties of zolpidem; clinical pharmacokinetics, pharmacodynamics and drug interactions; efficacy as a hypnotic; adverse effects; tolerance, dependence and withdrawal; relation to motor vehicle accidents and complex sleep behaviors; and new dosage forms.

EXPERT OPINION

Approved doses of zolpidem (10 mg for adults, 5 mg for the elderly) are consistently effective in reducing sleep latency and consequently increasing sleep duration in patients with insomnia. However, favorable effects on sleep maintenance are observed less consistently. Residual daytime effects are unlikely with recommended doses, and provided that at least 8 h elapse prior to arising. Hypnotic efficacy is maintained with repeated nightly use, and the risk of rebound insomnia is low. Dependence and abuse of zolpidem are no more likely to occur than with typical benzodiazepines. Newly available novel dosage forms of zolpidem have increased therapeutic options for patients with insomnia variants such as sleep maintenance insomnia and middle-of-the-night awakening.

Negative impact of migraine on quality of life after 4 weeks of treatment in patients with major depressive disorder

AIM

The impact of migraine on health-related quality of life (HRQoL) among patients with major depressive disorder (MDD) after acute antidepressant treatment has not been addressed. The aim of the present study was to investigate whether or not the negative impact of migraine on HRQoL among outpatients with MDD continued to have an effect after 4 weeks of venlafaxine treatment.

METHODS

A total of 135 outpatients with MDD were enrolled, who were then treated with venlafaxine 75 mg per day for 4 weeks in the present open-label study. Migraine was diagnosed based on the International Classification of Headache Disorders (2nd edn). Changes in Short-Form 36 (SF-36) and Hamilton Depression Rating Scale (HAMD) scores were the outcome measures. Multiple linear regression was used to assess whether migraine was an independent factor predicting SF-36 score after treatment.

RESULTS

Seventy-two participants (18M/54F) completed the 4-week treatment. Subjects with migraine had a poorer HRQoL in terms of bodily pain and mental health at baseline. Subjects with and without migraine showed significant improvement in all SF-36 subscales and depression after treatment, but subjects with migraine still had a poorer HRQoL regarding bodily pain and physical functioning after treatment as compared with those without migraine. Migraine could predict a negative outcome after treatment in the subscales of physical functioning, role limitations-physical, and role limitations-emotional.

CONCLUSIONS

Migraine may have a negative impact on the improvement of partial SF-36 subscales, especially on functional recovery, after acute treatment among outpatients with MDD. Whether additional intervention besides antidepressant treatment for migraine is indicated may need further study.

Comorbidities and factors related to discontinuation of pharmacotherapy among outpatients with major depressive disorder

OBJECTIVE

Although many studies have researched adherence to pharmacotherapy among patients with major depressive disorder (MDD), the effects of chronic depression, anxiety comorbidities, migraine, and other factors on adherence have rarely been studied. This study investigated which comorbidities and factors independently predicted discontinuation of pharmacotherapy among psychiatric outpatients with MDD.

METHODS

One hundred thirty-five subjects (34 men, 101 women) with MDD were enrolled. MDD and anxiety comorbidities were diagnosed using the Structured Clinical Interview for DSM-IV-TR (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision), migraine was diagnosed based on the International Classification of Headache Disorders, 2nd Edition, and depression severity was evaluated using the Hamilton Depression Rating Scale. Six months later, subjects' reasons for discontinuation were investigated, and Cox proportional hazards regression and logistic regression were used to investigate the independent factors predicting discontinuation.

RESULTS

Subjects with chronic depression, migraine, panic/agoraphobia, or posttraumatic stress disorder attended follow-up for longer before discontinuation than those without. Chronic depression and greater age independently predicted a longer follow-up before discontinuation. Concern about and intolerance of the side effects of antidepressants and lack of insight into MDD independently predicted discontinuation within 2 months. "Self-reported recovery" was the most common reason for discontinuation; however, 53.8% of the subjects who cited this reason did not reach full remission.

CONCLUSIONS

The impact of the duration of depression (chronic depression) on adherence may be more important than the severity of depression, anxiety comorbidities, and migraine. Education of MDD patients and society in general to improve understanding of MDD and antidepressants is needed to enhance adherence to pharmacotherapy.

Synthesis and anticancer activity of oxindole derived imidazo[1,5-a]pyrazines

A series of oxindole derivatives of imidazo[1,5-a]pyrazines were prepared and confirmed by 1H NMR, mass and HRMS data. These compounds were evaluated for their anticancer activity against a panel of 52 human tumor cell lines derived from nine different cancer types: leukemia, lung, colon, CNS, melanoma, ovarian, renal, prostate and breast. Among them compound 7l showed significant anticancer activity with GI50 values ranging from 1.54 to 13.0 μM. Cell cycle arrest was observed in G0/G1 phase upon treatment of A549 cells with 6.5 μM (IC50) concentration of compound 7l and induced apoptosis. This was confirmed by Annexin V-FITC as well as DNA fragmentation analysis and interestingly this compound (7l) did not affect the normal cells.

Efficacy of combination therapy with tamsulosin and zolpidem on nocturia in patients with benign prostatic hyperplasia

Introduction

We examined the efficacy of combination therapy with α1-blocker tamsulosin and hypnotic zolpidem in patients who had suffered from sleep disturbance associated with nocturia.

Material and methods

A total of 35 patients diagnosed with nocturia with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH) were studied. After treatment with tamsulosin for 4 weeks, 16 patients dissatisfied with nocturia (nocturiaquality of life index ≥4) and suspected to have sleep disturbance (Athens Insomnia Scale ≥6) received additional treatment with tamsulosin and zolpidem for 2 weeks. Outcomes were evaluated by the International Prostate Symptom Score (IPSS) and quality of life index (QOL), Athens Insomnia Scale (AIS) and nocturia-quality of life index (nocturia-QOL).

Results

After monotherapy with tamsulosin, significant reductions in IPSS (18.9 ±3.8 to 9.9 ±3.0, p <0.001), QOL (4.5 ±0.9 to 3.2 ±0.9, p <0.001) and nocturia episodes (3.4 ±0.7 to 2.6 ±1.0, p <0.001) were observed. However 20 patients were dissatisfied with nocturia (nocturia- QOL ≥4). Among 20 patients, 16 patients were suspected to have sleep disturbances (AIS ≥6). In these patients, additional therapy with tamsulosin and zolpidem significantly reduced nocturia episodes (3.3 ±0.8 to 1.9 ±0.7, p <0.001), AIS (10.6 ±2.9 to 6.8 ±25, p <0.001) and nocturia – QOL (5.6 ±0.5 to 3.6 ±1.1, p <0.001) compared with patients after treatment with tamsulosin only.

Conclusions

Combination therapy with tamsulosin and zolpidem may be useful for patients with BPH dissatisfied with nocturia and suspected to have sleep disturbance.

Pharmacokinetic interaction between zolpidem and ciprofloxacin in healthy volunteers

Our objective was to evaluate a possible pharmacokinetic interaction between zolpidem and ciprofloxacin in healthy volunteers. The study consisted of two periods: Period 1 (reference), when each volunteer received a single dose of 5 mg zolpidem and Period 2 (test), when each volunteer received a single dose of 5 mg zolpidem and 500 mg ciprofloxacin. Between the two periods, the subjects were treated for 5 days with a single daily dose of 500 mg ciprofloxacin. Plasma concentrations of zolpidem were determined during a 12-hour period following drug administration. Pharmacokinetic parameters of zolpidem administered in each treatment period were calculated using non-compartmental analysis and the data from two periods were compared to determine statistically significant differences. In the two periods of treatments, the mean peak plasma concentrations (Cmax) were 75.73±28.34 ng/ml (zolpidem alone) and 80.58±22.40 ng/ml (zolpidem after pre-treatment with ciprofloxacin). The tmax, times taken to reach Cmax, were 0.91±0.42 and 1.44±0.61 h, respectively, and the total areas under the curve (AUC0-∞) were 300.2±115.5 and 438.1±142.6 ng h/ml, respectively. The half-life of zolpidem was 2.39±0.53 h when administered alone and 3.34±0.87 h after pre-treatment with ciprofloxacin. These differences were statistically significant for Cmax, tmax, AUC0-∞, half-life and mean residence time. Ciprofloxacin interacts with zolpidem in healthy volunteers, raising its bioavailability by about 46%. This magnitude of effect is likely to be clinically significant.

Somatic symptoms: an important index in predicting the outcome of depression at six-month and two-year follow-up points among outpatients with major depressive disorder

BACKGROUND

Few studies have simultaneously compared the ability of depression, anxiety, and somatic symptoms to predict the outcome of major depressive disorder (MDD). This study aimed to compare the MDD outcome predictive ability of depression, anxiety, and somatic severity at 6-month and 2-year follow-ups.

METHODS

One-hundred and thirty-five outpatients (men/women=34/101) with MDD were enrolled. Depression and anxiety were evaluated by the Hamilton Depression Rating Scale, Hospital Anxiety and Depression Scale, and depression subscale of the Depression and Somatic Symptoms Scale (DSSS). Somatic severity was evaluated by the somatic subscale of the DSSS. Subjects undergoing pharmacotherapy in the follow-up month were categorized into the treatment group; the others were categorized into the no-treatment group. Multiple linear regressions were used to identify the scales most powerful in predicting MDD outcome.

RESULTS

Among the 135 subjects, 119 and 106 completed the 6-month and 2-year follow-ups, respectively. Somatic severity at baseline was correlated with the outcomes of the three scales at the two follow-ups. After controlling for demographic variables, somatic severity independently predicted most outcomes of the three scales at the two follow-ups in the no-treatment group and the cost of pharmacotherapy and DSSS score at the 6-month follow-up in the treatment group.

LIMITATIONS

Division of the subjects into treatment and no-treatment groups was not based on randomization and bias might have been introduced.

CONCLUSIONS

Somatic severity was the most powerful index in predicting MDD outcome. Psychometric scales with appropriate somatic symptom items may be more accurate in predicting MDD outcome.

A randomized, placebo-controlled trial of an amino acid preparation on timing and quality of sleep

This study was an outpatient, randomized, double-blind, placebo-controlled trial of a combination amino acid formula (Gabadone) in patients with sleep disorders. Eighteen patients with sleep disorders were randomized to either placebo or active treatment group. Sleep latency and duration of sleep were measured by daily questionnaires. Sleep quality was measured using a visual analog scale. Autonomic nervous system function was measured by heart rate variability analysis using 24-hour electrocardiographic recordings. In the active group, the baseline time to fall asleep was 32.3 minutes, which was reduced to 19.1 after Gabadone administration (P = 0.01, n = 9). In the placebo group, the baseline latency time was 34.8 minutes compared with 33.1 minutes after placebo (P = nonsignificant, n = 9). The difference was statistically significant (P = 0.02). In the active group, the baseline duration of sleep was 5.0 hours (mean), whereas after Gabadone, the duration of sleep increased to 6.83 (P = 0.01, n = 9). In the placebo group, the baseline sleep duration was 7.17 +/- 7.6 compared with 7.11 +/- 3.67 after placebo (P = nonsignificant, n = 9). The difference between the active and placebo groups was significant (P = 0.01). Ease of falling asleep, awakenings, and am grogginess improved. Objective measurement of parasympathetic function as measured by 24-hour heart rate variability improved in the active group compared with placebo. An amino acid preparation containing both GABA and 5-hydroxytryptophan reduced time to fall asleep, decreased sleep latency, increased the duration of sleep, and improved quality of sleep.

Insomnia treatment options for women

This article describes the circumstances under which women may develop insomnia and the various treatment options, including hypnotic medication and nonpharmacologic approaches. The efficacy and safety of these treatments are reviewed. The choice of treatment depends on the nature of the insomnia, the stage of a woman's life, the presence of medical or mental health conditions, the availability of treatments, and personal preference. For immediate, short-term relief of acute insomnia, hypnotic medication, especially the nonbenzodiazepines (zolpidem, zopiclone, eszopiclone) are options. For chronic insomnia, insomnia-specific cognitive and behavioral therapies are generally the interventions of choice.

Transient global amnesia-like episode due to mistaken intake of zolpidem: drug safety concern in the elderly

OBJECTIVE

Chronic insomnia is a common phenomenon among the elderly. Inaccurate handling and use of hypnotics in the elderly has become an important issue in patient safety. Older people who self-medicate often have a high risk for medication errors.

METHODS AND RESULTS

We described here the case of a 65-year-old woman who experienced recurrent transient anterograde amnesia, anxiety, bewilderment, and repetitive questioning that lasted for 2 to 3 hours after erroneously taking zolpidem. This mistake was due to the similarity in appearance between zolpidem and her newly prescribed anticholesterol drug, ezetimibe.

CONCLUSIONS

History of medication, particularly as regards hypnotics, should be carefully reviewed when a patient presents with transient global amnesia-like symptoms. The inadvertent use of drugs may be an underrecognized phenomenon among the elderly who self-medicate. When prescribing a new drug to elderly patients, especially hypnotics, physicians and pharmacists should educate them and their families about the proper use of these medications for their own safety.

6-Substituted 2-(N-trifluoroacetylamino)imidazopyridines induce cell cycle arrest and apoptosis in SK-LU-1 human cancer cell line

A series of 6-substituted 2-(N-trifluoroacetylamino)imidazopyridines have been synthesized and their bioactivities were evaluated. Compounds 6a, 6c, and 11a were the most active compounds with modest cytotoxic activity against six human cancer cell lines U251 (glioma), PC-3 (prostate), K-562 (leukemia), HCT-15 (colon), MCF7 (breast) and SK-LU-1 (lung). The cell cycle analysis showed that compounds 6a, 6c, and 11a induce a G2/M phase cell cycle arrest on SK-LU-1 cell line where inhibition of CDK-1 and CDK-2 may be implicated.

Short-term clarithromycin administration impairs clearance and enhances pharmacodynamic effects of trazodone but not of zolpidem

The kinetic and dynamic interactions of 5 mg zolpidem and 50 mg trazodone with 500 mg clarithromycin (4 doses given over 32 h) were investigated in a 5-way double crossover study with 10 healthy volunteers. The five treatment conditions were: placebo + placebo; zolpidem + placebo; zolpidem + clarithromycin; trazodone + placebo; and trazodone + clarithromycin. Coadministration of clarithromycin increased trazodone area under the curve, prolonged elimination half-life, increased peak plasma concentration (C(max)), and reduced oral clearance. In contrast, clarithromycin had no significant effect on any kinetic parameter for zolpidem. Clarithromycin did not potentiate sedation caused by zolpidem. However, clarithromycin coadministered with trazodone significantly increased self- and observer-rated sedation and ratings of feeling "spacey." Thus, short-term clarithromycin coadministration significantly impairs trazodone clearance, elevates plasma concentrations, and enhances sedative effects. However, clarithromycin has no significant kinetic or dynamic interaction with zolpidem.

Chemical-genetic profiling of imidazo[1,2-a]pyridines and -pyrimidines reveals target pathways conserved between yeast and human cells

Small molecules have been shown to be potent and selective probes to understand cell physiology. Here, we show that imidazo[1,2-a]pyridines and imidazo[1,2-a]pyrimidines compose a class of compounds that target essential, conserved cellular processes. Using validated chemogenomic assays in Saccharomyces cerevisiae, we discovered that two closely related compounds, an imidazo[1,2-a]pyridine and -pyrimidine that differ by a single atom, have distinctly different mechanisms of action in vivo. 2-phenyl-3-nitroso-imidazo[1,2-a]pyridine was toxic to yeast strains with defects in electron transport and mitochondrial functions and caused mitochondrial fragmentation, suggesting that compound 13 acts by disrupting mitochondria. By contrast, 2-phenyl-3-nitroso-imidazo[1,2-a]pyrimidine acted as a DNA poison, causing damage to the nuclear DNA and inducing mutagenesis. We compared compound 15 to known chemotherapeutics and found resistance required intact DNA repair pathways. Thus, subtle changes in the structure of imidazo-pyridines and -pyrimidines dramatically alter both the intracellular targeting of these compounds and their effects in vivo. Of particular interest, these different modes of action were evident in experiments on human cells, suggesting that chemical–genetic profiles obtained in yeast are recapitulated in cultured cells, indicating that our observations in yeast can: (1) be leveraged to determine mechanism of action in mammalian cells and (2) suggest novel structure–activity relationships.

We have shown that chemical–genetic screening allows structure–activity studies of chemical compounds at a very high resolution. In analyzing the effects of closely related imidazo-pyridine and -pyrimidine compounds, we found two compounds that likely act as oxidizing agents, yet target different organelles. The imidazo-pyridine affected mitochondrial functions whereas the imidazo-pyrimidine caused nuclear DNA damage. Remarkably, the only difference between these two compounds is the presence of a nitrogen atom at position 8. Thus, in addition to demonstrating the potential for high resolution in chemical–genetic studies, our work suggests that subtle changes in compound chemistry can be exploited to target different intracellular compartments with very different biological effects. Finally, we show that chemical–genetic profiling in yeast can be used to infer mode of action in mammalian cells. The specificity of compound 15 in eliciting a nuclear DNA damage response in evolutionarily diverse eukaryotes suggests that it will be of great utility in studying the cellular response to nuclear oxidative damage.

Emerging approaches for the syntheses of bicyclic imidazo[1,2-x]-heterocycles

Imidazo-[1,2-x]heterocycles are versatile building blocks for use in both a 'drug hunters' quest to discover new leads and a chemical biologists search for effective molecular tools in 'cell perturbation' studies. At the front end of the drug discovery flow chart, the last 5-10 years have witnessed the discovery of new high-throughput methodologies which very quickly have enabled access to virtual libraries of these chemo-types in the realm of 10(7) derivatives. Interestingly, these often neglected cores in patent cooperation treaty (PCT) applications appear in several highly effective marketed drugs, completing the medicinal chemists search for clinical success. Such rigid chemo-types, all containing a bridgehead nitrogen atom, are thus poised for an ever increasing impact on the discovery and development of new molecular therapeutics. The following mini-review will briefly cover therapeutic utility, chemical methodologies and automation developed to enable preparation of arrays of these chemo-types in a high-throughput manner. Synthetic emphasis is placed on a 3-component-3-center isocyanide based multi-component reaction (IMCR), which spans solution, solid phase, flourous and microwave assisted organic synthesis.

Efficacy and safety of zolpidem extended release in elderly primary insomnia patients

OBJECTIVES

To evaluate the clinical efficacy and safety of zolpidem extended release for the treatment of primary insomnia in elderly patients.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group clinical trial was conducted. A total of 205 (117 women, 88 men; mean age 70.2 +/- 4.5 years) Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-defined primary insomnia patients were randomized to 3 weeks of nightly treatment with either zolpidem extended release 6.25 mg or placebo; 198 patients completed the study.

RESULTS

Relative to placebo, zolpidem extended release 6.25 mg significantly decreased wake time after sleep onset during the first six hours of the night, as measured by polysomnogram (PSG). PSG latency to persistent sleep was reduced and PSG total sleep time was increased, both at nights 1/2 and 15/16. Patient self-report measures were significantly better with zolpidem extended-release 6.25 mg than with placebo throughout treatment. Some PSG measures indicated a worsening of sleep for a single night after abrupt discontinuation of zolpidem extended release. No next-morning residual effects were observed. The overall incidence and nature of adverse events was comparable between the two groups.

CONCLUSIONS

Zolpidem extended release 6.25 mg improved both sleep maintenance and sleep induction in elderly primary insomnia patients during three weeks of administration.

Les médicaments du sommeil et de la vigilance et leurs indications

This paper is a review of the use of drugs in sleep and wakefulness disorders. Insomnia is more often a symptom than an autonomic disorder. Good knowledge of the clinical facts is required before prescribing hypnotics. Sedative drugs are potentially hypnotics; yet, melatonin is not sedative and may be considered to resynchronise of sleep phases. Stimulant drugs are prescribed in attention disorders; methylphenidate is the more frequently used. Narcolepsy, which is characterized by daytime sleepiness and irresistible episodes of sleep, is treated by an alpha1 noradrenergic stimulant modafinil which has no amphetaminic properties.

Pharmacokinetic and Pharmacodynamic Interactions Between Zolpidem and Caffeine

The kinetic and dynamic interaction of caffeine and zolpidem was evaluated in a double-blind, single-dose, six-way crossover study of 7.5 mg zolpidem (Z) or placebo (P) combined with low-dose caffeine (250 mg), high-dose caffeine (500 mg), or placebo. Caffeine coadministration modestly increased maximum plasma concentration (C(max)) and area under the plasma concentration-time curve of zolpidem by 30-40%, whereas zolpidem did not significantly affect the pharmacokinetics of caffeine or its metabolites. Compared to P+P, Z+P significantly increased sedation, impaired digit-symbol substitution test performance, slowed tapping speed and reaction time, increased EEG relative beta amplitude, and impaired delayed recall. Caffeine partially, but not completely, reversed most pharmacodynamic effects of zolpidem. Thus, caffeine only incompletely reverses zolpidem's sedative and performance-impairing effects, and cannot be considered as an antidote to benzodiazepine agonists.

Gaboxadol, a selective extrasynaptic GABA(A) agonist, does not generalise to other sleep-enhancing drugs: a rat drug discrimination study

Gaboxadol is a selective extrasynaptic GABA(A) receptor agonist (SEGA) which enhances slow-wave sleep, and may act principally at extrasynaptic GABA(A)alpha4betadelta receptors. Drug discrimination is a very useful approach for exploring in vivo pharmacological similarities and differences between compounds and was therefore used to compare gaboxadol and zolpidem, an established hypnotic drug, against zopiclone, S-zopiclone, indiplon and tiagabine, all of which have been reported to enhance sleep. Gaboxadol generalised to itself, but not to zolpidem, zopiclone, S-zopiclone, R-zopiclone, indiplon or tiagabine. By contrast, zolpidem generalised to itself, zopiclone, S-zopiclone and indiplon, but not to R-zopiclone (the inactive enantiomer of zopiclone), gaboxadol or tiagabine. This suggests that zolpidem, zopiclone, S-zopiclone and indiplon share a discriminative stimulus, which may be mediated by their efficacy at GABA(A)alpha1betagamma receptors. Gaboxadol and tiagabine each have a different discriminative stimulus from all the other drugs tested.

Diagnosis and management of insomnia in dialysis patients

Sleep-related complaints affect 50-80% of patients on dialysis. Sleep disorders impair quality of life significantly. Increasing evidence suggests that sleep disruption has a profound impact both on an individual and on a societal level. The etiology of sleep disorders is often multifactorial: biologic, social, and psychological factors play a role. This is especially true for insomnia, which is the most common sleep disorder in different populations, including patients on dialysis. Biochemical and metabolic changes, lifestyle factors, depression, anxiety, and other underlying sleep disorders can all have an effect on the development and persistence of sleep disruption, leading to chronic insomnia. Insomnia is defined as difficulty initiating or maintaining sleep, or having nonrestorative sleep. It is also associated with daytime consequences, such as sleepiness and fatigue, and impaired daytime functioning. In most cases, the diagnosis of insomnia is based on the patient's history, but in some patients objective assessment of sleep pattern may be necessary. Optimally the treatment of insomnia involves the combination of both pharmacologic and nonpharmacologic approaches. In some cases acute insomnia resolves spontaneously, but if left untreated, it may lead to chronic sleep problems. The treatment of chronic insomnia is often challenging. There are only a few studies specifically addressing the management of this sleep disorder in patients with chronic renal disease. Considering the polypharmacy and altered metabolism in this patient population, treatment trials are clearly needed. This article reviews the diagnosis of sleep disorders with a focus on insomnia in patients on dialysis.

Zolpidem extended-release

Zolpidem extended-release, or controlled-release (CR), is a new formulation of zolpidem, a nonbenzodiazepine hypnotic. It is indicated in the US for the treatment of insomnia, characterised by difficulties with sleep onset and/or sleep maintenance. Zolpidem CR is a dual-layered tablet; one layer releases zolpidem immediately and a second layer provides a slower release of additional zolpidem for maintenance of plasma zolpidem concentrations. Efficacy of zolpidem CR was assessed in two 3-week, randomised, double-blind, placebo-controlled, phase III polysomnography trials in younger adult (aged 18-64 years) or elderly (aged > or =65 years) patients with primary insomnia. Patients received nightly zolpidem CR (12.5mg in younger adult and 6.25mg in elderly patients). Efficacy was assessed objectively on nights 1, 2, 15 and 16. Patients who received zolpidem CR had significantly improved objective latency to persistent sleep, wake time after sleep onset and sleep efficiency on assessment nights compared with placebo recipients. In subjective assessments of sleep quality on day 2 and nights 15 and 22, significantly more zolpidem CR than placebo recipients gave favourable responses on a Patient Global Impression scale in the study in younger adult patients. In the other study, significantly more elderly patients in the zolpidem CR group rated their sleep as improved compared with the placebo group. Zolpidem CR was generally well tolerated and appears to have a tolerability profile similar to that of the original formulation of zolpidem.

Management of chronic insomnia in elderly persons

BACKGROUND

Chronic insomnia is common among the elderly These elderly patients are often viewed as difficult to treat, yet they are among the groups with the greatest need of treatment.

OBJECTIVE

This article reviews the literature on the management of chronic insomnia in elderly persons.

METHODS

A search of MEDLINE was conducted for articles published in English between January 1966 and March 2006 using the terms insomnia, behavioral therapy, estsazolsam, fluvsazepsam, qusazepsam, teMsazepsam, tvisazolsam, eszopiclone, zaleplon, zolpidem, mirtazapine, nefazodone, trazodone, and ramelteon. Articles were selected if they were meta-analyses or evidence-based reviews of therapeutic modalities; randomized controlled trials of nonpharmacologic or pharmacologic treatment; or review articles covering the characteristics and management of insomnia. Preference was given to meta-analyses, evidence-based reviews, and articles that included relevant new information.

RESULTS

Available options for the treatment of insomnia include nonpharmacologic approaches, foremost among them cognitive behavioral therapy, and pharmacotherapies, including chloral hydrate, barbiturates, over-the-counter (OTC) and prescription antihistamines, OTC dietary supplements (including melatonin), sedating antidepressants, benzodiazepine and nonbenzodiazepine sedative-hypnotics, and melatonin agonists. There is considerable evidence to support the effectiveness and durability of nonpharmacologic interventions for insomnia in adults of all ages, yet these interventions are underutilized. With some recent exceptions, the majority of identified studies of pharmacotherapy were of short duration (< or =6 weeks) and did not exclusively enroll older adults. Compared with the benzodiazepines, the nonbenzodiazepine sedative-hypnotics appeared to offer few, if any, significant clinical advantages in efficacy or tolerability in elderly persons. Newer agents with novel mechanisms of action and improved safety profiles, such as the melatonin agonists, hold promise for the management of chronic insomnia in elderly people.

CONCLUSIONS

Long-term use of sedative-hypnotics for insomnia lacks an evidence base and has traditionally been discouraged for reasons that include concerns about such potential adverse drug effects as cognitive impairment (anterograde amnesia), daytime sedation, motor incoordination, and increased risk of motor vehicle accidents and falls. In addition, the effectiveness and safety of long-term use of these agents remain to be determined. More research is needed to evaluate the long-term effects of treatment and the most appropriate management strategy for elderly persons with chronic insomnia.

8-Fluoroimidazo[1,2-a]pyridine: synthesis, physicochemical properties and evaluation as a bioisosteric replacement for imidazo[1,2-a]pyrimidine in an allosteric modulator ligand of the GABA A receptor

8-Fluoroimidazo[1,2-a]pyridine has been established as a physicochemical mimic of imidazo[1,2-a]pyrimidine, using both in silico and traditional techniques. Furthermore, a novel synthesis of a 3,7-disubstituted-8-fluoroimidazopyridine 3 has been developed and the utility of the physicochemical mimicry has been demonstrated in an in vitro system. Here, the 8-fluoroimidazopyridine ring contained in ligand 3 acts as a bioisosteric replacement for imidazopyrimidine in the GABA(A) receptor modulator 2.

Quantification of zolpidem in human plasma by high-performance liquid chromatography with fluorescence detection

A simple, reliable HPLC method with fluorescence detection (excitation 320 and emission 388 nm) was developed and validated for quantitation of zolpidem in human plasma. Following a single-step liquid-liquid extraction, the analyte and internal standard (quinine) were separated using an isocratic mobile phase on a reversed-phase C(18) column. The lower limit of quantitation was 1.8 ng/mL, with a relative standard deviation of less than 5%. A linear dynamic range of 1.8-288 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 1.7-4.8 and 1.2-2.3%, respectively. The between-batch and within-batch accuracy was 95.3-100.4 and 95.5-102.7%, respectively. Frequently coadministered drugs did not interfere with the described methodology. Stability of zolpidem in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is simple and repeatable enough to be used in pharmacokinetic studies.

Postural Instability and Consequent Falls and Hip Fractures Associated with Use of Hypnotics in the Elderly

The aim of this review is to establish the relationship between treatment with hypnotics and the risk of postural instability and as a consequence, falls and hip fractures, in the elderly. A review of the literature was performed through a search of the MEDLINE, Ingenta and PASCAL databases from 1975 to 2005. We considered as hypnotics only those drugs approved for treating insomnia, i.e. some benzodiazepines and the more recently launched 'Z'-compounds, i.e. zopiclone, zolpidem and zaleplon. Large-scale surveys consistently report increases in the frequency of falls and hip fractures when hypnotics are used in the elderly (2-fold risk). Benzodiazepines are the major class of hypnotics involved in this context; falls and fractures in patients taking Z-compounds are less frequently reported, and in this respect, zolpidem is considered as at risk in only one study. It is important to note, however, that drug adverse effect relationships are difficult to establish with this type of epidemiological data-mining. On the other hand, data obtained in laboratory settings, where confounding factors can be eliminated, prove that benzodiazepines are the most deleterious hypnotics at least in terms of their effects on body sway. Z-compounds are considered safer, probably because of their pharmacokinetic properties as well as their selective pharmacological activities at benzodiazepine-1 (BZ(1)) receptors. The effects of hypnotics on balance, gait and equilibrium are the consequence of differential negative impacts on vigilance and cognitive functions, and are highly dose- and time-dependent. Z-compounds have short half-lives and have less cognitive and residual effects than older medications. Some practical rules need to be followed when prescribing hypnotics in order to prevent falls and hip fractures as much as possible in elderly insomniacs, whether institutionalised or not. These are: (i) establish a clear diagnosis of the sleep disorder; (ii) take into account chronic conditions leading to balance and gait difficulties (motor and cognitive status); (iii) search for concomitant prescription of psychotropics and sedatives; (iv) use half the recommended adult dosage; and (v) declare any adverse effect to pharmacovigilance centres. Comparative pharmacovigilance studies focused on the impact of hypnotics on postural stability are very much needed.