Zaleplon: a review of its use in the treatment of insomnia

Eszopiclone for the treatment of insomnia

Eszopiclone, a single-isomer, non-benzodiazepine hypnotic agent, is approved for use in the US for the treatment of insomnia for patients who have difficulty falling asleep (sleep latency) as well as for those who have difficulty staying asleep (sleep maintenance). Efficacy in sleep maintenance has not been consistently demonstrated with previous hypnotics, and long-term efficacy and safety data are lacking for these agents. In clinical trials, eszopiclone 3 mg significantly improved objective and subjective sleep measures in transient and chronic insomnia in adults. Nightly treatment with eszopiclone 1 mg effectively induced sleep in elderly patients and the 2-mg dose effectively induced and maintained sleep. The ability of eszopiclone 2 mg to significantly improve next-day functioning and daytime alertness (as demonstrated by a reduction in the number and duration of naps) in the elderly is an important finding in clinical trials, and is unique to the class of hypnotic agents for the treatment of insomnia. Eszopiclone was well tolerated in clinical trials < or = 12 months duration, with no clinically significant evidence of pharmacological tolerance, rebound insomnia or dependence. The most frequently reported adverse event was unpleasant taste. Eszopiclone is the only non-benzodiazepine sedative-hypnotic (in the Schedule IV class under the Controlled Substances Act) to be evaluated as a long-term treatment for chronic insomnia.

Ramelteon

Ramelteon, approved in the US for the treatment of insomnia characterised by difficulty with sleep onset, is a highly selective agonist for the melatonin MT1/MT2 receptors, which are believed to mediate the circadian rhythm in mammals. Ramelteon has negligible affinity for the MT3 binding sites and other receptors in the brain, including the opiate, dopamine, benzodiazepine and serotonin receptors, which may explain the lack of significant adverse events and lack of abuse or dependence potential observed with ramelteon. In three clinical trials in patients with chronic insomnia, ramelteon 8mg was effective in reducing sleep latency, without being associated with any significant or clinically relevant residual effects. It also generally increased total sleep time and, where assessed, sleep efficiency. In a first-night-effect model of transient insomnia, ramelteon 8mg was significantly more effective than placebo at reducing sleep latency and increasing total sleep time. Ramelteon was generally well tolerated; the most commonly reported adverse events occurring in more ramelteon than placebo recipients were somnolence (5% vs 3%), fatigue (4% vs 2%) and dizziness (5% vs 3%). Adverse events were mostly mild or moderate in nature. Ramelteon has been shown to have no potential for abuse or dependence.

Uso indevido de benzodiazepínicos: um estudo com informantes-chave no município de São Paulo

Este estudo teve por objetivo compreender a prática de prescrição, dispensação e uso prolongado de benzodiazepínicos, a partir da visão de profissionais de saúde e de usuários crônicos dessas substâncias. A amostra foi composta por técnica de bola de neve, totalizando19 informantes-chave. As entrevistas semi-estruturadas foram gravadas e transcritas para análise. A maioria dos entrevistados relatou ser freqüente a obtenção de prescrição de benzodiazepínicos por solicitações junto aos médicos, sem necessidade de consulta formal. Os usuários relataram histórico de uso prolongado (entre 2 e 8 anos) com finalidades outras que não apenas a terapêutica. Enfatizaram também a facilidade em adquirir a medicação e a falta de orientação médica sobre os cuidados necessários durante o tratamento. O estudo sugere que a ocorrência de uso indevido envolve não apenas o sistema de controle da dispensação, mas uma série de outros fatores, entre os quais as atitudes dos profissionais de saúde.

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.

Hipnoindutores e insônia

O objetivo deste artigo de atualização é o de descrever brevemente o perfil, a utilização clínica e a indicação de alguns dos sedativos e compostos hipnóticos mais utilizados. Cerca de 2/3 de todas as prescrições hipnóticas vão para o uso crônico. Os benzodiazepínicos estão entre as drogas mais prescritas mundialmente. As mulheres, os idosos e os pacientes psiquiátricos e clínicos estão entre os usuários crônicos de hipnóticos. O zolpidem é, atualmente, o hipnótico mais prescrito na maioria dos países. Parece ser mais seguro em comparação aos benzodiazepínicos e poderia ser uma opção para o uso de longo prazo e controlado ("quando necessário"). Os antidepressivos sedativos encontram-se também entre as medicações mais prescritas para sedação em pacientes com insônia nos EUA e no Reino Unido. São descritos efeito sedativo e uso de trazodona, mirtazapina, doxepina e amitriptilina. Os autores também discutem o uso de melatonina e suas propriedades sedativas e o uso racional de antipsicóticos sedativos para insônia crônica, em especial em pacientes psiquiátricos. Finalmente, alguns compostos fitoterápicos são mencionados.

Correlates and consequences of chronic insomnia

Approximately one half of patients with insomnia have a primary psychiatric disorder such as a depression or anxiety. Insomnia is associated with increased risk of new or recurrent psychiatric disorders, increased daytime sleepiness with consequent cognitive impairment, poorer prognoses, reduced quality of life and high healthcare-related financial burden. Emerging data suggest that resolution of insomnia may improve psychiatric outcomes, which underscores the importance of vigorous treatment. Unfortunately, only a small percentage of patients receive such care. An ideal monotherapeutic strategy would treat both depression and insomnia. There are, however, only a handful of modern antidepressants that objectively improve sleep maintenance problems, and none do so without causing adverse next-day effects such as sedation. Thus, a significant number of patients must take adjunctive hypnotic medications, even though longer-term efficacy has not been established. New and emerging anti-insomnia agents may prove useful in the long-term treatment of chronic insomnia. Further research is needed to establish the benefits of such treatment.

Advances in the management of insomnia

Insomnia is a prevalent disorder, altering night time sleep, daytime mood and performance. Current treatment strategies, used separately or in combination, include pharmacological, circadian, behavioural and cognitive therapy. An increased diversity of available hypnotics with different potency, pharmacodynamic and pharmacokinetic profiles and improved side effect profiles provides more flexibility in designing individual treatment strategies. Melatonin, a pineal hormone with acute sleep-promoting and chronobiotic properties, allows additional possibilities in treating insomnia and circadian sleep disorders. Current studies of processes involved in normal sleep regulation and pathophysiology of insomnia should result in the development of new medications based on physiological mechanisms of sleep.

Current patterns and future directions in the treatment of insomnia

BACKGROUND

Despite the high prevalence and the high burden associated with chronic insomnia, it remains largely unrecognized and often inadequately treated by physicians.

METHODS

A review was undertaken of the literature on barriers to both acute and chronic treatment of insomnia, as well as recent trials of pharmacologic and nonpharmacologic agents for insomnia.

RESULTS

Obstacles to appropriate treatment of the condition include outdated insomnia management guidelines, which have contributed to US Food and Drug Administration restrictions on longer-term prescription of hypnotic agents; lack of research demonstrating the benefit of treating insomnia; and fears of tolerance and withdrawal effects of long-term use of hypnotic agents, as well as an absence of longer-term, randomized, controlled, double-blind trials of existing agents used to treat insomnia.

CONCLUSIONS

There is evidence that improved sleep may improve outcome in some medical and psychiatric illnesses. Both behavioral and pharmacologic therapies have shown efficacy in chronic insomnia. In addition, a recent 6-month, randomized, controlled study has demonstrated that at least one agent may be safe and effective in longer-term use.

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.

The pharmacology and mechanisms of action of new generation, non-benzodiazepine hypnotic agents

The new generation hypnotic drugs, zolpidem, zopiclone and zaleplon, are at least as efficacious in the clinic as benzodiazepines and may offer advantages in terms of safety. These drugs act through the BZ binding sites associated with GABAA receptors, but show some differences from benzodiazepines in pharmacological effects and mechanisms of action. Of particular interest is the finding that zolpidem shows a wide separation between doses producing sedative effects and those giving rise to other behavioural actions, and induces less tolerance and dependence than benzodiazepines. Zolpidem also demonstrates selectivity for GABAA receptors containing alpha1 subunits. Recent studies using genetically modified mice have confirmed that receptors containing alpha1 subunits play a particularly important role in mediating sedative activity, thus providing an explanation for the pharmacological profile of zolpidem.

Comparative pharmacokinetics and pharmacodynamics of short-acting hypnosedatives: zaleplon, zolpidem and zopiclone

Benzodiazepines have historically been the mainstay of treatment for sleeping disorders, yet they have many shortcomings. A new group of sedative hypnotic agents has been developed for this purpose. Similar to the benzodiazepines, zaleplon, zolpidem and zopiclone have activity at the GABA receptor complex, yet they appear to have more selectivity for certain subunits of the GABA receptor. This produces a clinical profile that is more efficacious with fewer side effects. Zaleplon, zolpidem and zopiclone are structurally distinct. Due to variation in binding to the GABA receptor subunits, these three compounds show subtle differences in their effect on sleep stages, and as antiepileptics, anxiolytics and amnestics. The duration of action of zaleplon, zolpidem and zopiclone can be related to their individual pharmacokinetic profile, which subsequently determines the time course of drug effect. Each of these compounds has a unique pharmacokinetic profile with different bioavailability, volume of distribution and elimination half-lives. Zaleplon has a rapid elimination so there are fewer residual side effects after taking a single dose at bedtime. By comparison, zolpidem and zopiclone have a more delayed elimination so there may be a prolonged drug effect. This can result in residual sedation and side effects but may be useful for sustained treatment of insomnia with less waking during the night. There are also differences in potency based on plasma concentrations suggesting that there are differences in binding to the GABA receptor complex. Although zaleplon has a much lower bioavailability (30%), the treatment dose is similar to zolpidem and zopiclone (bioavilaibility of 70%) because of the increased potency of zaleplon. The pharmacokinetics and pharmacodynamics of zaleplon, zolpidem and zopiclone are significantly different from benzodiazepines. The new drugs are sufficiently unique from each other to allow customisation of treatment for various types of insomnia. While zaleplon may be best indicated for the delayed onset of sleep, zolpidem and zopiclone may be better indicated for maintaining a complete night's sleep. Only the patient's symptoms and response to treatment will dictate the best course of treatment.

[Treatment of insomnia in children: pharmacological aspects]

In the last few years topics related to sleep in children have aroused increased interest. Most hypnotic drugs and sedatives used to treat adult insomnia are not recommended in children. Even so, 56% of pediatricians use medication to treat childhood sleep disorders. We review the different causes of insomnia in children from birth to school age. The various therapeutic options are discussed and the therapeutic methods that have been demonstrated to be most effective in the various types of insomnia. The most frequent hypnotic drugs used in insomnia treatment are benzodiazepines and non-benzodiazepine hypnotics such as imidazopyridine, pyrazolopyrimidine and cyclopyrrolone. Few studies have been published on the use of melatonin in insomnia although several reports suggest that is useful and relatively safe in the treatment of insomnia in school-aged children. In children with insomnia, pediatricians should first of all obtain information about the characteristics of insomnia and the environmental characteristics surrounding the child and his/her family. Once an organic cause has been ruled out, treatment should be based on informing the parents about sleep physiology and on training them in sleep hygiene and the acquisition of sleep habits. When pharmacological treatment is required, it should be carefully selected using the smallest effective doses. Melatonin seems to have a promising future in insomnia treatment in healthy children and in those with neurological disorders.

Clinically important drug interactions with zopiclone, zolpidem and zaleplon

Insomnia, an inability to initiate or maintain sleep, affects approximately one-third of the American population. Conventional benzodiazepines, such as triazolam and midazolam, were the treatment of choice for short-term insomnia for many years but are associated with adverse effects such as rebound insomnia, withdrawal and dependency. The newer hypnosedatives include zolpidem, zaleplon and zopiclone. These agents may be preferred over conventional benzodiazepines to treat short-term insomnia because they may be less likely to cause significant rebound insomnia or tolerance and are as efficacious as the conventional benzodiazepines. This review aims to summarise the published clinical drug interaction studies involving zolpidem, zaleplon and zopiclone. The pharmacokinetic and pharmacodynamic interactions that may be clinically important are highlighted. Clinical trials have studied potential interactions of zaleplon, zolpidem and zopiclone with the following types of drugs: cytochrome P450 (CYP) inducers (rifampicin), CYP inhibitors (azoles, ritonavir and erythromycin), histamine H(2) receptor antagonists (cimetidine and ranitidine), antidepressants, antipsychotics, antagonists of benzodiazepines and drugs causing sedation. Rifampicin significantly induced the metabolism of the newer hypnosedatives and decreased their sedative effects, indicating that a dose increase of these agents may be necessary when they are administered with rifampicin. Ketoconazole, erythromycin and cimetidine inhibited the metabolism of the newer hypnosedatives and enhanced their sedative effects, suggesting that a dose reduction may be required. Addition of ethanol to treatment with the newer hypnosedatives resulted in additive sedative effects without altering the pharmacokinetic parameters of the drugs. Compared with some of the conventional benzodiazepines, fewer clinically important interactions appear to have been reported in the literature with zaleplon, zolpidem and zopiclone. The fact that these drugs are newer to the market and have not been as extensively studied as the conventional benzodiazepines may be the reason for this. Another explanation may be a difference in CYP metabolism. While triazolam and midazolam are biotransformed almost entirely via CYP3A4, the newer hypnosedatives are biotransformed by several CYP isozymes in addition to CYP3A4, resulting in CYP3A4 inhibitors and inducers having a lesser effect on their biotransformation.

New drugs for insomnia: comparative tolerability of zopiclone, zolpidem and zaleplon

Insomnia affects 30-35% of people living in developed countries. The impact of insomnia on daytime functioning and its relationship with medical and psychiatric illnesses necessitate early treatment to prevent insomnia becoming persistent and to avoid the development of complications. However, pharmacological strategies must achieve a balance between sedative and adverse effects. In the last 30 years, benzodiazepines have been the preferred drugs for the treatment of insomnia. Benzodiazepines act nonselectively at two central receptor sites, named omega(1) and omega(2), which are located in different areas of the CNS. The sedative action of benzodiazepines is related to omega(1) receptors, whereas omega(2) receptors are responsible for their effects on memory and cognitive functioning. According to their pharmacokinetic profile, benzodiazepines can be classified into three groups: short half-life (<3 hours), medium half-life (8-24 hours) and long half-life (>24 hours). The newer non-benzodiazepine agents zopiclone, zolpidem and zaleplon have a hypnosedative action comparable with that of benzodiazepines, but they display specific pharmacokinetic and pharmacodynamic properties. These three 'Z' agents all share a short plasma half-life and limited duration of action. In addition, these agents are selective compounds that interact preferentially with omega(1) receptors (sedative effect), whereas benzodiazepines also interact with omega(2) receptors (adverse effects on cognitive performance and memory). Zaleplon is characterised by an ultrashort half-life (approximately 1 hour). Zolpidem and zopiclone have longer half-lives (approximately 2.4 and 5 hours, respectively). These properties, together with the low risk of residual effect, may explain the limited negative influences of these agents on daytime performance. Psychomotor tasks and memory capacities appear to be better preserved by non-benzodiazepine agents than by benzodiazepines. When present, cognitive deficits almost exclusively coincide with the peak plasma concentration. In particular, impairment can emerge in the first hours after drug administration, whereas psychomotor and memory tests carried out 7-8 hours later (i.e. in the morning) generally show no relevant alterations. As with benzodiazepines, the three 'Z' non-benzodiazepine agents should be used for a limited period, even in chronic relapsing conditions. Further evaluation is needed of the safety of hypnosedative medications in the long-term management of insomnia.

Mixed drug intoxication involving zaleplon ("Sonata")

Zaleplon ("Sonata") is a pyrazolopyrimidine derivative approved for use in the United States for the treatment of insomnia. To date, there has been little data in the toxicological literature where zaleplon has been implicated as causing a fatal intoxication, either alone or in combination with other drugs. This report documents a case where zaleplon was identified in a suicide by multiple drug ingestion. The following zaleplon concentrations were found: heart blood 2.2mg/l; bile 8.6mg/l and urine 1.4mg/l. Zaleplon was also detected but not quantitated in the kidney and liver.

Preference of insomniac patients between a single dose of zolpidem 10 mg versus zaleplon 10 mg

We assessed the preference of insomniac patients between a single dose of 10 mg zolpidem or zaleplon, respectively, administered in random order on two consecutive nights. Fifty-three patients (mean age 52.2 years, 51% females) with a history of recurrent episodes of insomnia and currently complaining of difficulties in falling asleep were included into a randomized, double-blind, cross-over study by 12 general practitioners. After each night, the patients were asked to fill in a sleep questionnaire and visual analogue scales (VAS) to subjectively assess both the quality of sleep (in the morning) and the quality of the day (in the evening). After the second study night, patients' self-assessed preference was established through a drug preference questionnaire. 62% of patients preferred zolpidem, while 38% preferred zaleplon (p = 0.08). The quality of sleep items getting to sleep and quality of sleep were significantly more improved after zolpidem (p = 0.03 and p < 0.0001, respectively). On the VAS, subjective sleep quality was significantly better after zolpidem (p < 0.0001). Diurnal awakeness and quality of day life were satisfying in both groups, without significant difference. The subjective total duration of sleep was 8.0 h for zolpidem and 8.1 h for zaleplon (n.s.). Safety was good and similar between the two drugs. Insomniac patients tended to prefer zolpidem to zaleplon on both nocturnal and diurnal assessments. These results provide additional information for the physician's choice, based on the patient's preference for a given drug.

Hypnotics: an update

This update reviews recent developments and advances in the therapeutic and side-effect profile of the benzodiazepine receptor agonists (BZRAs), the generally accepted drug class of choice for the symptomatic treatment of insomnia. All the approved BZRAs, depending on their pharmacokinetic profile, improve and maintain sleep. The major recent advance is in the enhanced diversity of the pharmacokinetic profiles of these drugs, and thus in the flexibility available to the clinician in treatment strategy. Also, during the past decade the nature and significance of the side effects associated with the BZRAs and their determinants, dose and half-life, have been identified and clarified. The important remaining question is whether, and how, the efficacy and safety of the BZRAs change with chronic use.

Consensus on Drug Treatment, Definition and Diagnosis for Insomnia

Thirty-four experts and a literature supervisor got together in order to reach a 'consensus' regarding the definition, diagnosis and pharmacological treatment of insomnia. Insomnia is a subjective perception of dissatisfaction with the amount and/or quality of sleep. It includes difficulty in initiating or maintaining sleep or early awakening with inability to fall asleep again. It is associated with complaints of non-restorative sleep and dysfunction of diurnal alertness, energy, cognitive function, behaviour or emotional state, with a decrease in quality of life. The diagnosis is based on clinical and sleep history, physical examination and additional tests, although polysomnography is not routinely indicated. Therapy should include treatment of the underlying causes, cognitive and behavioural measures and drug treatment. Hypnotic therapy can be prescribed from the onset of insomnia and non-benzodiazepine selective agonists of the GABA-A receptor complex are the drugs of first choice. It is recommended that hypnotic treatment be maintained in cases where withdrawal impairs the patient's quality of life and when all other therapeutic measures have failed. Experience suggests that intermittent treatment is better than continuous therapy. The available data do not confirm safety of hypnotics in pregnancy, lactation and childhood insomnia. Benzodiazepines are not indicated in decompensated chronic pulmonary disease but no significant adverse effects on respiratory function have been reported with zolpidem and zopiclone in stable mild to moderate chronic obstructive pulmonary disease and in treated obstructive sleep apnoea syndrome. Data for zaleplon are inconclusive. If the patient recovers subjective control over the sleep process, gradual discontinuation of hypnotic treatment can be considered.

Residual effects of middle-of-the-night administration of zaleplon and zolpidem on driving ability, memory functions, and psychomotor performance

Thirty healthy volunteers participated in this two-part study. Part 1 was a single-blind, two-period crossover design to determine the effects of a single dose of ethanol (0.03% < BAC < 0.05%) or ethanol-placebo on driving ability, memory, and psychomotor performance. Part 2 was a double-blind, five-period crossover design to measure the effects of a middle-of-the-night administration of zaleplon 10 or 20 mg, zolpidem 10 or 20 mg, or placebo on driving ability 4 hours after administration and memory and psychomotor performance 6 hours after administration. The on-the-road driving test consisted of operating an instrumented automobile over a 100-km highway circuit at a constant speed (95 km/h) while maintaining a steady lateral position between the right lane boundaries. The standard deviation of lateral position (SDLP) was the primary performance parameter of the driving test. The psychomotor and memory test battery consisted of the Word Learning Test, the Critical Tracking Test, the Divided Attention Test, and the Digit Symbol Substitution Test. Data for each part were analyzed separately using ANOVA for crossover designs. Zaleplon 10 and 20 mg did not significantly impair driving ability 4 hours after middle-of-the-night administration. Relative to placebo, after zolpidem 10 mg, SDLP was significantly elevated, but the magnitude of the difference was small and not likely to be of clinical importance. Memory and psychomotor test performance was unaffected after both doses of zaleplon and zolpidem 10 mg. In contrast, zolpidem 20 mg significantly increased SDLP and speed variability. Further, zolpidem 20 mg significantly impaired performance on all psychomotor and memory tests. Finally, driving performance, Digit Symbol Substitution Test, Divided Attention Test, and immediate and delayed free recall of the Word Learning Test were significantly impaired after ethanol. The results show that zaleplon (10 and 20 mg) is a safe hypnotic devoid of next-morning residual impairment when used in the middle of the night.

Treatment of insomnia in hospitalized patients

OBJECTIVE

To provide recommendations for the short-term management of insomnia in hospitalized patients and review patient assessment, nonpharmacologic treatment modalities, and selection of hypnotic medications.

DATA SOURCES

Review articles and primary literature representative of current knowledge regarding the treatment of insomnia were identified by MEDLINE search (1966-January 2001). Search terms included insomnia (sleep initiation and maintenance disorders), benzodiazepines, zaleplon, zolpidem, and trazodone.

DATA SYNTHESIS

Literature regarding the management of insomnia in hospitalized patients is limited; therefore, data pertinent to the treatment of ambulatory patients must be extrapolated to the inpatient setting. When evaluating insomnia in hospitalized patients, it seems reasonable to obtain a thorough history and physical examination to identify potential underlying etiologies. Treatment of these underlying etiologies should be considered. When the use of a sedative-hypnotic agent is necessary, medication and dose selection should be based on the pharmacokinetic and adverse effect profiles of each agent. Patent-specific characteristics should also be considered to provide effective treatment while minimizing adverse effects.

CONCLUSIONS

Nonpharmacologic approaches to the treatment of insomnia should be considered for hospitalized patients. When sedative-hypnotic medications must be administered, the pharmacokinetic profile of intermediate-acting benzodiazepines (e.g., lorazepam, temazepam) makes them good first-line agents. Zaleplon and zolpidem are also attractive hypnotic agents; however, they are typically reserved for second-line therapy due to cost. Trazodone may be an alternative for patients unable to take benzodiazepines.

Pharmacodynamic profile of Zaleplon, a new non-benzodiazepine hypnotic agent

The challenge in developing hypnotic agents for the treatment of insomnia is to balance the sedative effect needed at bedtime with the residual sedation on awakening. Zaleplon is a novel pyrazolopyrimidine hypnotic agent that acts as a selective agonist to the brain omega(1) receptor situated on the alpha(1) subunit of the GABA(A) receptor complex. Zaleplon was proven to be an effective hypnotic drug as it consistently and significantly reduced latency to persistent sleep in insomniac patients for doses of 10 mg and above in polysomnography studies. The pharmacodynamic profile of zaleplon on psychomotor performance, actual driving and cognitive function, including memory, was assessed in several randomized, double-blind, placebo-controlled studies in healthy young subjects as well as insomniac patients by using various positive controls (zolpidem, zopiclone, triazolam and flurazepam). The recommended hypnotic dose of zaleplon in young adults (10 mg) produced minimal or no impairment of psychomotor and memory performance even when administered during the night as little as 1 h before waking. No impairment of actual driving was observed when zaleplon 10 mg was administered either at bedtime or in the middle of the night as little as 4 h before waking. Zaleplon 20 mg, twice the recommended dose, generally produced significant impairment of performance and cognitive functions when these functions were measured at the time of peak plasma concentration, i.e. 1 h after dose administration, and no impairment of driving abilities was observed 4 h after a middle-of-the-night administration. In contrast, consistent detrimental residual effects on various aspects of psychomotor and cognitive functions were observed with the therapeutic doses of the various commonly prescribed hypnotic agents used as comparators, e.g. zolpidem 10 mg up to 5 h after dose administration, zopiclone 7.5 mg up to 10 h after, flurazepam 30 mg up to 14 h after and triazolam 0.25 mg up to 6 h after. Also, zolpidem 10 mg and zopiclone 7.5 mg were also shown to significantly impair driving ability the next morning when this was measured 4 h and up to 10 h after dose administration, respectively. The present review shows that zaleplon 10 mg has little or no residual effect when administered in the middle of the night, as late as 1 h before waking, and is devoid of impairment of driving abilities as assessed by actual driving 4 h after dose administration. The lack of clinically significant or minimally statistically significant residual effects of zaleplon even at its peak concentration may be explained by its unique pharmacokinetic (rapid elimination half-life) and pharmacodynamic (low affinity, and specific binding profile to various subunits of the GABA(A)receptor) profiles. These properties allow zaleplon to be used for treatment of symptoms only when they occur, either at bedtime or later in the night, without incurring significant risk of developing next-day impairment of psychomotor and cognitive functioning. Copyright 2001 John Wiley & Sons, Ltd.

Multiple-dose tolerability, pharmacodynamics, and pharmacokinetics of the quinolizinone hypnotic Ro 41-3696 in elderly subjects

The objectives of this double-blind, placebo-controlled study were to assess the multiple-dose tolerability, pharmacodynamics, and pharmacokinetics of the hypnotic agent Ro 41-3696 in elderly men and women (55-75 y of age). On day 1 and days 3-8, doses of 1, 3, 5, and 10 mg were administered sequentially to 4 groups of 10 subjects, 2 of whom received placebo. Psychomotor performance tests (tracking and attention) were conducted just before and at 1.5, 4, and 8 hours after drug intake on days 1, 4, 6, and 8. Memory was assessed at 24 hours after drug intake on days 1 and 8 by recall of a list of 10 words, which had been learned at 2 hours after intake. Ro 41-3696 was well tolerated at all dose levels. One subject dropped out of the study because of a hypersensitive skin reaction during treatment with 10 mg. Performance in both a tracking test and a memory search test was significantly affected by a dose of 10 mg and moderately affected by doses of 3 and 5 mg. The results of the 1-mg dose were indistinguishable from those of placebo. Long-term memory, as assessed by a word learning and recall test, showed the same pattern. Partial tolerance to the impairing effects in the psychometric tests developed over the course of treatment. Pharmacokinetics of both Ro 41-3696 and its O-desethyl metabolite Ro 41-3290 were dose proportional and time independent. Ro 41-3696 was absorbed and eliminated rapidly (time of maximum plasma concentration, approximately 1 hour; elimination half-life, approximately 2 hours). Plasma levels of Ro 41-3290 were higher than those of the parent drug, and it was more slowly eliminated (values for time of maximum plasma concentration and elimination half-life, approximately 2 and approximately 7 hours, respectively).