Safety and subjective sleep effects of ramelteon administration in adults and older adults with chronic primary insomnia: a 1-year, open-label study.

OBJECTIVE: To evaluate the long-term safety and subjective sleep effects of ramelteon in adults with chronic insomnia. METHOD: Subjects with primary insomnia (DSM-IV-TR criteria) for >or= 3 months received ramelteon nightly for 1 year; a 3-day placebo run out followed. Subjects aged >or=65 years received open-label ramelteon 8 mg (N = 248); those aged 18 to 64 years received ramelteon 16 mg (N = 965). Subjects completed sleep diaries and returned to the clinic at week 1 and at months 1, 2, 3, 4, 6, 8, 10, and 12 for safety assessments and investigator-performed Clinical Global Impressions. The study was conducted from February 2003 through September 2004. RESULTS: There were no noteworthy changes in vital signs, physical examinations, clinical chemistry, hematology, or urinalysis values and no electrocardiogram changes to suggest adverse cardiac effects. Endocrine values remained within normal range throughout treatment. Consistent statistically significant (p

Circadian phase-shifting effects of repeated ramelteon administration in healthy adults.

STUDY OBJECTIVES: To assess the ability of repeated daily oral ramelteon to facilitate re-entrainment of human circadian rhythms after an imposed phase advance of the sleep-wake cycle. METHODS: A total of 75 healthy adult volunteers aged 18-45 years remained in a sleep laboratory for 6 days and 5 nights; a 5-h phase advance in their sleep-wake cycle was imposed under dim-light conditions. Oral ramelteon (1,2, 4, or 8 mg once daily for 4 days) or placebo was administered 30 min before bedtime. The primary endpoint was the phase of the circadian rhythm as assessed by the time at which salivary melatonin concentrations declined below 3 pg/mL after morning awakening (dim-light melatonin offset [DLMoff]). RESULTS: After 4 days of once-daily treatment, participants receiving 1, 2, or 4 mg ramelteon exhibited statistically significant phase shifts in DLMoff of -88.0 (16.6), -80.5 (14.8), and -90.5 (15.2) minutes respectively, versus -7.1 (18.6) minutes for placebo (least-squares mean(SEM), p = 0.002, p = 0.003, p = 0.001, respectively). Change in DLMoff for the 8 mg dose of ramelteon, -27.9 (16.4) minutes, was not significantly different than that for placebo (p = 0.392). CONCLUSIONS: Ramelteon (1, 2, or 4 mg per day) administered before bedtime significantly advanced the phase of the circadian rhythm after a 5-h phase advance in the sleep-wake cycle. These findings suggest that ramelteon has potential as a specific therapy for circadian rhythm sleep disorders.

Circadian rhythmicity and the pharmacologic management of insomnia.

The circadian clock modulates timing of sleep and wakefulness. In certain situations, the circadian potentiation of wakefulness may interfere with desired sleep-scheduling, particularly in the elderly and shift workers. Known abnormalities of circadian regulation are defined by their impact on sleep-wake state expression. In delayed sleep phase syndrome, patients have trouble going to sleep and arising at reasonable hours and are alert in the evening and sleepy in the morning. Patients with advanced sleep phase syndrome are sleepy in the evening and awaken very early and alert in the morning. In shift-work sleep disorder, individuals attempt to wake and sleep out of phase with the circadian clock. As with jet lag, the clock is functioning normally, but the requirements on the clock are abnormal. Typical insomnia can also be associated with circadian rhythm alterations. Practice guidelines and clinical studies data are needed to lead appropriate therapy selection and effective management.

Human physiological models of insomnia.

Despite the wide prevalence and important consequences of insomnia, remarkably little is known about its pathophysiology. Available models exist primarily in the psychological domain and derive from the demonstrated efficacy of behavioral treatment approaches to insomnia management. However, these models offer little specific prediction about the anatomic or physiological foundation of chronic primary insomnia. On the other hand, a growing body of data on the physiology of sleep supports a reasonably circumscribed overview of possible pathophysiological mechanisms, as well as the development of physiological models of insomnia to guide future research. As a pragmatic step, these models focus on primary insomnia, as opposed to comorbid insomnias, because the latter is by its nature a much more heterogeneous presentation, reflecting the effects of the distinct comorbid condition. Current understanding of the regulation of sleep and wakefulness in mammalian brain supports four broad candidate areas: 1) disruption of the sleep homeostat; 2) disruption of the circadian clock; 3) disruption of intrinsic systems responsible for the expression of sleep states; or 4) disruption (hyperactivity) of extrinsic systems capable of over-riding normal sleep-wake regulation. This review examines each of the four candidate pathophysiological mechanisms and the available data in support of each. While studies that directly test the viability of each model are not yet available, descriptive data on primary insomnia favor the involvement of dysfunctional extrinsic stress-response systems in the pathology of primary chronic insomnia.

The human circadian system in normal and disordered sleep.

The human circadian system regulates rhythmicity in the human body and establishes normal sleep and wake phases. The suprachiasmatic nuclei (SCN), located in the hypothalamus above the optic chiasm, make up the human pacemaker known as the circadian or biological clock, but other essential parts of the circadian system include the pineal gland, retina, and retinohypothalamic tract. The importance of light in resetting the intrinsic human circadian cycle, the intrinsic period of which is slightly longer than 24 hours, ensures that the human cycle will stay entrained to the earth's 24-hour daily cycle. Within the SCN neurons, circadian rhythmicity is generated by the regular transcription of proteins. Since the circadian system is the foundation of the sleep-wake cycle, disorders and abnormalities in sleep are often connected with disorders or abnormalities in the circadian system. Circadian rhythm sleep disorders, such as jet lag syndrome and shift work sleep disorder, are those specifically attributed to dysfunctions or insufficiencies in the circadian system. Taking into consideration the preeminence of the circadian clock in timing sleep, it is likely that other sleep disorders, such as insomnia, are also linked to circadian system abnormalities.

Long-term use of sedative hypnotics in older patients with insomnia.

BACKGROUND AND PURPOSE: Insomnia is a common problem that increases with age and can last months to years. While substantial data establish the efficacy and safety of short-acting hypnotic therapy for the management of short-term insomnia using benzodiazepines receptor agonists (BzRAs), there are few studies on the continued efficacy and safety of these drugs when used for sustained periods. This paper reports the results of a 1-year open-label extension phases of two randomized, double-blind trials of zaleplon. PATIENTS AND METHODS: In the open-label phase, older patients self-administered zaleplon nightly from 6 to 12 months and were then followed through a 7-day single-blind placebo-controlled run-out period. RESULTS: The safety profile in this population of older adults was similar to that observed in a short-term trial of an equivalent population. The data also suggested that long-term therapy produced and maintained statistically significant improvement in time to persistent sleep onset, duration of sleep and number of nocturnal awakenings (P<0.001 for each variable) for treatment durations of up to 12 months. Discontinuation was not associated with rebound insomnia. CONCLUSION: The open-label trial of long-term hypnotic therapy with zaleplon 5 and 10 mg suggests that they are safe and effective for the treatment of insomnia in older patients. Placebo-controlled, double-blind trials are needed in zaleplon and other BzRAs to confirm these results.

Brief wake episodes modulate sleep-inhibited luteinizing hormone secretion in the early follicular phase.

To determine the influence of sleep, sleep stage, and time of day on the dynamics of pulsatile LH secretion in the early follicular phase (EFP) of the menstrual cycle, 11 normal women underwent simultaneous polysomnographic monitoring of sleep and measurement of LH in frequent sampling studies during a 40-h protocol that consisted of one night of normal sleep and one night of sleep deprivation followed by an afternoon nap. The interpulse interval of LH was longer during sleep than wake whether it occurred at night or during the day (P < 0.002), implying a decrease in GnRH pulse frequency associated with sleep in the EFP. LH pulse amplitude was greater during sleep than wake (P < 0.001) and greater pulse amplitudes were associated with longer interpulse intervals during sleep (P < 0.005), but not wake. An interaction between sleep and time of day was observed for mean LH, with lower mean LH levels during sleep than wake at night (P < 0.02), but not during the day. Wakefulness was more likely to be associated with an LH pulse than were stages I/II, III/IV (slow wave), or rapid eye movement sleep (P < 0.005). In addition, the probability of wakefulness within the sleep episode increased 5-15 min before the onset of LH pulses (relative to randomly selected nonpulse LH; P < 0.05), suggesting that wakefulness was the primary event. In the absence of sleep, there was an effect of time of day on mean LH (P < 0.02) and LH pulse amplitude (P < 0.03), with greatest values seen during the evening. In conclusion, in the EFP, inhibition of LH pulse frequency is related to sleep rather than time of day. During periods of sleep, LH pulses occur most commonly in association with brief awakenings, suggesting that interruptions from sleep allow escape from the inhibitory effect of sleep on pulsatile GnRH secretion. A separate effect of time of day on LH pulse dynamics in the absence of sleep was also observed with evening augmentation of LH pulse amplitude and mean level; however, additional studies will be required to determine whether this represents a true circadian effect.

Epidemiology of insomnia and the need for diagnosis and treatment.

Insomnia is a common complaint of patients, yet not all patients have primary insomnia. Insomnia can be a significant health problem and may also accompany aging, stress, depression, and other illnesses. Several barriers exist to treatment, but incorporating simple questions may serve as step in guiding diagnosis and treatment.

Tolerance to daytime sedative effects of H1 antihistamines.

Sedation is the principal side effect of first generation H1 antihistamines, and recent studies have suggested that this side effect should limit the clinical application of these drugs. The sedative effect also underlies the use of these first-generation drugs as nonprescriptive remedies for insomnia. In both cases, the potential for tolerance to the sedative effect of these drugs is an important issue for which there are few objective data. In the study reported here, 15 healthy men age 18 to 50 years received either diphenhydramine 50 mg or placebo twice a day for 4 days in a randomized, double-blind, crossover trial design. Dependent measures included objective and subjective assessments of sleepiness and computer-based tests of psychomotor performance. Both objective and subjective measures of sleepiness showed significantly higher levels on day 1 for diphenhydramine compared to placebo. By day 4, however, levels of sleepiness on diphenhydramine were indistinguishable from placebo. Similarly, diphenhydramine produced significant impairment of performance that was completely reversed by day 4. These data provide the first objective confirmation that tolerance develops to the sedative effect of a prototypical first-generation H1 antihistamine, diphenhydramine. On this dosing regimen, tolerance was complete by the end of 3 days of administration. While other antihistamines and dosing regimens may differ, these results suggest that tolerance to the sedation produced by these drugs develops with remarkable rapidity.

Management of insomnia--the role of zaleplon.

CONTEXT: Insomnia is the most frequently reported sleep symptom, severely affecting up to 15% of the US population. The need to effectively treat this disorder is underscored by the significant adverse consequences on the productivity, safety, overall health, and quality of life of the affected individual. Pharmacologic intervention has traditionally involved the use of benzodiazepine receptor agonists (BzRAs), for which efficacy and general safety have been established. OBJECTIVE: The purpose of this paper is to examine the potentially unique role of zaleplon in the treatment of insomnia. DATA SOURCE: The clinical experience of the authors was critically applied to peer-reviewed published papers or abstracts regarding zaleplon, which were identified via MEDLINE (1995-September 2000). RESULTS: Adverse effects, usually related to residual sedation, impose limits on the use of older BzRAs and have prompted the development of new sleep medications with advantageous adverse event profiles. Zaleplon demonstrates a very rapid onset and offset of effect that permits symptomatic rather than prophylactic administration, resulting in comparable efficacy and reduced risk of the adverse effects associated with longer half-life agents. CONCLUSIONS: The characteristics of zaleplon may translate into distinct and significant clinical advances in the treatment of insomnia.