Advances in the management of insomnia

Zolpidem Overdose: A Dilemma in Mental Health

Sleeping pills are one of the most common drugs taken by adults when afflicted by insomnia. Adverse effects of pharmacotherapy, however, should not be overlooked, and monitoring is needed to check for an overdose of sleeping pills. We reviewed zolpidem overdose and patient suicide with benefits and disadvantages of pharmacotherapy. Cases of adverse effects concerning the central nervous system, including delirium and hallucination, as well as abnormal behavior during sleep, are commonly reported among patients who have taken zolpidem for more than 1 year. The serious problem of long-term prescription to medication can lead to a higher mortality rate of insomniac patients. An alternative to medication for treating insomnia is cognitive behavioral therapy, which can improve sleeping habits. Cognitive behavioral therapy induces patients to recognize and change the negative thoughts that affect their sleep. Medical providers should be aware of the adverse effects of sleep inducers and provide sufficient information to their patients about them. When establishing treatment plans, they should encourage patients to make the proper decisions and try to reduce the adverse effects of any medication as much as possible.

Zolpidem's use for insomnia

Zolpidem is a short-acting non-benzodiazepine hypnotic drug that belongs to the imidazopyridine class. In addition to immediate-release (IR) and extended-release (ER) formulations, the new delivery forms including two sublingual tablets [standard dose (SD) and low dose (LD)], and an oral spray form have been recently developed which bypass the gastrointestinal tract. So far, Zolpidem has been studied in several clinical populations: cases poor sleepers, transient insomnia, elderly and non-elderly patients with chronic primary insomnia, and in comorbid insomnia. Peak plasma concentration (Tmax) of zolpidem-IR occurs in 45 to 60min, with the terminal elimination half-life (t½) equating to 2.4h. The extended-release formulation results in a higher concentration over a period of more than 6h. Peak plasma concentration is somewhat shorter for the sublingual forms and the oral spray, while their t½ is comparable to that of zolpidem-IR. Zolpidem-IR reduces sleep latency (SL) at recommended doses of 5mg and 10mg in elderly and non-elderly patients, respectively. Zolpidem-ER at doses of 6.25mg and 12.5mg, improves sleep maintenance in elderly and non-elderly patients, respectively, 4h after its administration. Sublingual zolpidem-LD (5mg) and zolpidem oral spray are indicated for middle-of-the-night (MOTN) wakefulness and difficulty returning to sleep, while sublingual zolpidem-SD (10mg) is marketed for difficulty falling asleep. With their array of therapeutic uses and their popularity among physicians and patients; this review describes the clinical pharmacology, indications and uses, identifying withdrawal symptoms, abuse and dependence potentials, and adverse drug reactions are discussed.

Orexin receptor antagonism: an ascending multiple-dose study with almorexant

The objectives of this study were to investigate the multiple-dose tolerability, safety, pharmacokinetics, and pharmacodynamics of the dual orexin receptor antagonist almorexant. Healthy subjects received daily doses of almorexant (100, 200, 400 or 1000 mg) or placebo in the morning for four days followed by two days with evening administration (Days 5-6). Each dose level was investigated in a new group of 10 subjects (eight active, two placebo, 1:1 sex). Dose-dependent increases in frequency and intensity were observed for somnolence and other adverse events. Pharmacokinetics at steady state showed rapid absorption, low concentrations eight hours post-dose, and minimal accumulation. Following evening, administration absorption was delayed and C(max) decreased. Almorexant at 400 and 1000 mg administered in the morning reduced vigilance, alertness, visuomotor coordination, and motor coordination assessed in a psychometric test battery. Polysomnography recordings following evening administration showed a trend towards shorter latency to sleep stages 3 and 4, and shorter latency to, and longer time in, rapid-eye-movement sleep at higher doses when compared to placebo. Whether these findings in healthy subjects translate into relevant sleep-enabling effects in insomnia patients needs to be investigated in future studies.

Treating insomnia: Current and investigational pharmacological approaches

Chronic insomnia affects a significant proportion of young adult and elderly populations. Treatment strategies should alleviate nighttime symptoms, the feeling of nonrestorative sleep, and impaired daytime function. Current pharmacological approaches focus primarily on GABA, the major inhibitory neurotransmitter in the central nervous system. Benzodiazepine receptor agonists (BzRA) have been a mainstay of pharmacotherapy; the classical benzodiazepines and non-benzodiazepines share a similar mode of action and allosterically enhance inhibitory chloride currents through the GABA(A) receptor, a ligand-gated protein comprising 5 subunits pseudosymmetrically arranged around a core anion channel. Variations in GABA(A) receptor subunit composition confer unique pharmacological, biophysical, and electrophysiological properties on each receptor subtype. Classical benzodiazepines bind non-selectively to GABA(A) receptors containing a gamma2 subunit, whereas non-benzodiazepine hypnotics bind with higher relative affinity to alpha1-containing receptors. The non-benzodiazepine compounds generally represent an improvement over benzodiazepines as a result of improved binding selectivity and pharmacokinetic profiles. However, the enduring potential for amnestic effects, next day residual sedation, and abuse and physical dependence, particularly at higher doses, underscores the need for new treatment strategies. Novel pharmacotherapies in development act on systems believed to be specifically involved in the regulation of the sleep-wake cycle. The recently approved melatonin receptor agonist, ramelteon, targets circadian mechanisms. Gaboxadol, an investigational treatment and a selective extrasynaptic GABA(A) receptor agonist (SEGA), targets GABA(A) receptors containing a delta subunit, which are located outside the synaptic junctions of thalamic and cortical neurons thought to play an important regulatory role in the onset, maintenance, and depth of the sleep process.

Eszopiclone, a Nonbenzodiazepine Sedative-Hypnotic Agent for the Treatment of Transient and Chronic Insomnia

OBJECTIVE

This paper reviews the pharmacologic and pharmacokinetic properties, clinical efficacy, and safety profile of the nonbenzodiazepine cyclopyrrolone agent eszopiclone in the management of adult patients with insomnia.

METHODS

Recent studies, abstracts, reviews, and consensus statements published in English were identified through searches of MEDLINE (1966-December 2005), International Pharmaceutical Abstracts (1970 December 2005), and PharmaProjects (1990-December 2005) using the search terms eszopiclone, cyclopyrrolone, insomnia, nonbenzodiazepine, and zopiclone enantiomer. Selected information provided by the manufacturer of eszopiclone was included, as were all pertinent clinical trials.

RESULTS

Eszopiclone is rapidly absorbed after oral administration, with Tmax achieved within approximately 1 hour and a terminal-phase elimination half-life of approximately 6 hours. Approximately 52% to 59% of a dose is weakly bound to plasma protein. Eszopiclone is extensively metabolized by oxidation and demethylation. In vitro studies have indicated that the cytochrome P450 (CYP) isozymes CYP3A4 and CYP2E1 are involved in the biotransformation of eszopiclone; therefore, drugs that induce or inhibit these CYP isozymes may affect the metabolism of eszopiclone. Eszopiclone is excreted in the urine as racemic zopiclone at <10% of the orally administered dose. Six Phase III clinical trials were identified that evaluated the safety profile and efficacy of eszopiclone, 1 in healthy subjects with transient insomnia and 5 in patients with primary chronic insomnia (3 in younger adults and 2 in the elderly). In the trials in younger adults, eszopiclone significantly improved sleep efficiency, sleep latency, wake time after sleep onset, number of awakenings, number of nights awakened weekly, total sleep time, and quality and depth of sleep compared with placebo (P<0.05). In the trials in elderly patients, who received eszopiclone 2 mg or placebo for 2 weeks, eszopiclone was associated with significantly shorter sleep latency compared with placebo (P<0.004), as well as a significant decrease in the cumulative number of naps (P<0.05). The most commonly reported drug-related, dose-responsive adverse event in clinical trials of eszopiclone 2 and 3 mg was bitter taste (17% and 34%, respectively), followed by dizziness (5% and 7%) and dry mouth (5% and 7%). Somnolence occurred at an incidence of 4% to 9% with both doses. Tolerance or rebound insomnia was not reported.

CONCLUSIONS

Eszopiclone represents an effective and well-tolerated option for the treatment of insomnia. In the absence of published studies comparing eszopiclone with similar hypnotic agents (eg, zolpidem, zaleplon, zopiclone), it is not yet possible to evaluate its efficacy relative to other agents used for insomnia.

Insomnia

The pathogenesis of insomnia in an individual usually is multifaceted. Effective treatments require a thorough evaluation to determine the factors that need to be addressed. Pharmacologic treatments generally are safe and effective for short-term use. Long-term hypnotic use remains controversial because of the potential risk of tolerance and dependency. Various cognitive and behavioral treatments for insomnia have been shown to be effective in the management of insomnia. For long-term follow-up, multicomponent cognitive behavioral therapy, alone or in combination with hypnotic use, has been shown to be superior to hypnotic use alone.

Pineal attrition, loss of cognitive plasticity, and onset of puberty during the teen years: is it a modern maladaptation exposed by evolutionary displacement?

Cognitive plasticity, a developmental trait that promotes acquisition of complex skills such as language or playing musical instruments, diminishes substantially during puberty. The loss of plasticity has been attributed to surge of sex steroids during adolescence, but the phenomenon remains poorly understood. We hypothesize that pineal involution during puberty may contribute to plasticity decay. The pineal gland produces melatonin, the level of which declines dramatically during onset of puberty. Emerging evidence suggest that melatonin may modulate cognitive plasticity, independent of the effects of sex steroids, and low sex steroids and high melatonin may be simultaneously required to maintain cognitive plasticity. Potential mechanisms by which melatonin may modulate plasticity are examined within the sleep and hippocampal long-term potentiation frameworks. Implications for psychiatric conditions that involve sleep disorders and learning dysfunctions such as schizophrenia and autism are discussed, and the potential adaptive roles of postprandial and postcoital sleep are explored. From the Darwinian perspective, development and reproductive maturity may represent distinct phases that require tailored cognitive strategies to maximize fitness. While cognitive flexibility and susceptibility to new skills may be paramount during development, reduced cognitive flexibility and increased cognitive determinism may enable more efficient responses to stimuli during adulthood. Thus, cognitive plasticity and cognitive determinism may represent trade-off adaptations and different dimensions of intelligence. The decline of plasticity and emergence of puberty during the second decade may be relics of prehistoric times when the human lifespan was short and the environment was relatively simple and static. Today, when the environment is more complex and dynamic, and humans are living far longer, the early obsolescence of plasticity during puberty may represent a Darwinian inefficiency exposed by evolutionary displacement. Regulation of plasticity may be a systemic phenomenon, as exemplified by the association of learning disability with allergic conditions, a form of immune plasticity dysfunction. Ramifications for other plastic functions that decline during puberty such as wound healing and hyaline cartilage regeneration are explored. Like the plasticity of immunity and cognition, the plasticity of hyaline cartilage during youth may enable hosts to respond to ecologic opportunities and generate the optimally adapted adult phenotype. Pineal involution may represent a potential target for therapeutic extension or restoration of plasticity after puberty. Extending plasticity may have far-reaching consequences for human evolution.