Hypnosedative-induced complex behaviours : incidence, mechanisms and management

The clinical and forensic toxicology of Z-drugs

The Z-drugs zolpidem, zopiclone, and zaleplon were hailed as the innovative hypnotics of the new millennium, an improvement to traditional benzodiazepines in the management of insomnia. Increasing reports of adverse events including bizarre behavior and falls in the elderly have prompted calls for caution and regulation. Z-drugs have significant hypnotic effects by reducing sleep latency and improving sleep quality, though duration of sleep may not be significantly increased. Z-drugs exert their effects through increased γ-aminobutyric acid (GABA) transmission at the same GABA-type A receptor as benzodiazepines. Their pharmacokinetics approach those of the ideal hypnotic with rapid onset within 30 min and short half-life (1-7 h). Zopiclone with the longest duration of action has the greatest residual effect, similar to short-acting benzodiazepines. Neuropsychiatric adverse events have been reported with zolpidem including hallucinations, amnesia, and parasomnia. Poisoning with Z-drugs involves predominantly sedation and coma with supportive management being adequate in the majority. Flumazenil has been reported to reverse sedation from all three Z-drugs. Deaths from Z-drugs are rare and more likely to occur with polydrug overdose. Z-drugs can be detected in blood, urine, oral fluid, and postmortem specimens, predominantly with liquid chromatography-mass spectrometry techniques. Zolpidem and zaleplon exhibit significant postmortem redistribution. Zaleplon with its ultra-short half-life has been detected in few clinical or forensic cases possibly due to assay unavailability, low frequency of use, and short window of detection. Though Z-drugs have improved pharmacokinetic profiles, their adverse effects, neuropsychiatric sequelae, and incidence of poisoning and death may prove to be similar to older hypnotics.

In the Zzz zone: the effects of Z-drugs on human performance and driving

Despite their improved pharmacokinetic profile, the Z-drugs, zolpidem, zopiclone, and zaleplon, have a spectrum of adverse effects comparable to benzodiazepines. This review focuses on the impairment from Z-drugs on cognition, behavior, psychomotor performance, and driving ability. Z-drugs are short-acting GABA agonists that reduce sleep latency without disturbing sleep architecture. Bizarre behavioral effects have prompted warnings on the prescription, dispensation, and use of Z-drugs. Psychomotor impairment, falls, and hip fractures are more likely to occur with Z-drugs that have longer half-lives, that are taken at higher-than-recommended doses and when mixed with other psychoactive substances including alcohol. Zopiclone and higher doses of zolpidem are more likely to cause anterograde amnesia than zaleplon. Z-drugs, especially zolpidem, are associated with complex behaviors such as sleepwalking, sleep-driving, and hallucinations. Patients taking zopiclone and zolpidem have an increased risk of motor vehicle collisions, over double that of unexposed drivers. Driving impairment occurs with zopiclone and higher doses of zolpidem but is unlikely to occur after 4 h post-zaleplon administration. The residual effect of Z-drugs on next-day cognitive and psychomotor performance has significant impact on lifestyle, safety, and occupational considerations, including motor vehicle and machine operation. The risk-benefit analysis of Z-drugs in the treatment of insomnia, particularly in the elderly, may not favor treatment due to the increased risks of falls and motor vehicle collisions. Prescribers should warn patients taking Z-drugs of minimum time thresholds before they operate machinery or drive motor vehicles.

Managing insomnia: an overview of insomnia and pharmacologic treatment strategies in use and on the horizon

This review explores basic sleep physiology, the mechanism of action for each class of hypnotic agents, their clinical application based on pharmacodynamic and pharmacokinetic factors, and potential pharmacologic sleep-inducing mechanisms of future hypnotics. The paper challenges the reader to understand the neuroscientific basis of insomnia and use this knowledge to guide prescription of hypnotic agents. Currently indicated hypnotic agents are discussed with regard to their mechanism of drug action and clinical application. A broader discussion is developed throughout this paper regarding other non-indicated agents that may improve sleep and describing newer pharmacological treatments that may become available in the future for use in sleep disorders and their comorbid conditions.

Association between GABA(A) receptor subunit gene cluster and zolpidem-induced complex sleep behaviors in Han Chinese

STUDY OBJECTIVES

To investigate and elucidate the role of GABA(A) receptor subunits, specifically the 2 genetic markers at the GABA(A) α1 and GABA(A) α6 receptors, in zolpidem-induced complex sleep behaviors (CSBs).

DESIGN

Genetic association study.

SETTING

Kaohsiung Medical University-affiliated hospitals, Kaohsiung, Taiwan.

PATIENTS

30 zolpidem-induced CSB subjects and 37 controls.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

The χ(2) test demonstrated an association between the A15G variant at the GABA(A) α1 receptor subunit gene and zolpidem-induced CSBs (P = 0.007). The adjusted odds ratio of the GABA(A) α1 receptor subunit genotype for the risk of zolpidem-induced CSBs was approximately 10 (OR = 9.99, 95% CI = 1.82, 74.87; P = 0.013).

CONCLUSIONS

The finding reveals that the A15G variant at the GABA(A) α1 receptor subunit gene confers a high risk of zolpidem-induced CSBs and may be considered in clinical services.

A comparison of complex sleep behaviors with two short-acting Z-hypnosedative drugs in nonpsychotic patients

OBJECTIVE

Complex sleep behaviors (CSBs) are classified as "parasomnias" in the International Classifcation of Sleep Disorders, Second Edition (ICSD-2). To realize the potential danger after taking two short-acting Z-hypnosedative drugs, we estimated the incidence of CSBs in nonpsychotic patients in Taiwan.

METHODS

Subjects (N = 1,220) using zolpidem or zopiclone were enrolled from the psychiatric outpatient clinics of a medical center in Taiwan over a 16-month period in 2006-2007. Subjects with zolpidem (N = 1,132) and subjects with zopiclone (N = 88) were analyzed. All subjects completed a questionnaire that included demographic data and complex sleep behaviors after taking hypnotics.

RESULTS

Among zolpidem and zopiclone users, 3.28% of patients reported incidents of somnambulism or amnesic sleep-related behavior problems. The incidence of CSBs with zolpidem and zopiclone were 3.27%, and 3.41%, respectively, which was signifcantly lower than other studies in Taiwan.

CONCLUSION

These results serve as a reminder for clinicians to make inquiries regarding any unusual performance of parasomnic activities when prescribing zolpidem or zopiclone.

Two cases of zolpidem-associated homicide

Zolpidem is the most commonly prescribed medication for the short-term treatment of insomnia. Adverse reactions include nightmares, confusion, and memory deficits. Reported rare adverse neuropsychiatric reactions include sensory distortions such as hallucinations. Previous research has identified 4 factors that may place a patient at increased risk of zolpidem-associated psychotic or delirious reactions: (1) concomitant use of a selective serotonin reuptake inhibitor (SSRI), (2) female gender, (3) advanced age, and (4) zolpidem doses of 10 mg or higher. In this article, 2 cases are presented in which individuals killed their spouses and claimed total or partial amnesia. Neither individual had a history of aggressive behavior. Both had concomitantly taken 10 mg or more of zolpidem in addition to an SSRI (paroxetine).

Sleep and violence

OPINION STATEMENT

Treatment of violent behaviors in sleep depends on the underlying condition and a correct identification of the causative disorder is mandatory. After eliminating possible precipitating factors, pharmacological treatment is often required to control violent sleep behaviors. Although no drugs are specifically approved for the treatment of parasomnias and placebo-controlled trials are lacking in these patient populations, clonazepam is considered the drug of choice in the management of both Non-REM and REM parasomnias. Benzodiazepines may cause unwanted side effects especially in older individuals and tolerance is sometime observed. Melatonin and pramipexole may represent alternative options in REM sleep behavior disorder. Hypnosis therapy may be considered in arousal disorders when pharmacological treatment is contraindicated or ineffective. Management of nocturnal frontal lobe epilepsy include a first-step pharmacological approach with antiepileptic drugs (eg, carbamazepine, oxcarbazepine or other drugs effective on partial seizures), but surgical options may be considered in drug refractory patients. The published evidence for the efficacy of various treatments relies mostly upon case series or case reports.

Parasomnias: an updated review

Parasomnias are abnormal behaviors emanating from or associated with sleep. Sleepwalking and related disorders result from an incomplete dissociation of wakefulness from nonrapid eye movement (NREM) sleep. Conditions that provoke repeated cortical arousals, or promote sleep inertia lead to NREM parasomnias by impairing normal arousal mechanisms. Changes in the cyclic alternating pattern, a biomarker of arousal instability in NREM sleep, are noted in sleepwalking disorders. Sleep-related eating disorder (SRED) is characterized by a disruption of the nocturnal fast with episodes of feeding after an arousal from sleep. SRED is often associated with the use of sedative-hypnotic medications; in particular, the widely prescribed benzodiazepine receptor agonists. Recently, compelling evidence suggests that nocturnal eating may in some cases be a nonmotor manifestation of Restless Legs Syndrome (RLS). rapid eye movement (REM) Sleep Behavior Disorder (RBD) is characterized by a loss of REM paralysis leading to potentially injurious dream enactment. The loss of atonia in RBD often predates the development of Parkinson's disease and other disorders of synuclein pathology. Parasomnia behaviors are related to an activation (in NREM parasomnias) or a disinhibition (in RBD) of central pattern generators (CPGs). Initial management should focus on decreasing the potential for sleep-related injury followed by treating comorbid sleep disorders. Clonazepam and melatonin appear to be effective therapies in RBD, whereas paroxetine has been reported effective in some cases of sleep terrors. At this point, pharmacotherapy for other parasomnias is less certain, and further investigations are necessary.

Restless nocturnal eating: a common feature of Willis-Ekbom Syndrome (RLS)

STUDY OBJECTIVES

To determine the frequency of nocturnal eating (NE) and sleep related eating disorder (SRED) in restless legs syndrome (RLS) versus psychophysiological insomnia (INS), and the relationship of these conditions with dopaminergic and sedative-hypnotic medications.

DESIGN

Prospective case series.

SETTING

Sleep disorders center.

PATIENTS

Newly diagnosed RLS or INS.

INTERVENTION

RLS or INS pharmacotherapy with systematic follow up interview for NE/SRED.

MEASUREMENTS AND RESULTS

Patients presenting with RLS (n = 88) or INS (n = 42) were queried for the presence of NE and SRED. RLS patients described nocturnal eating (61%) and SRED (36%) more frequently than INS patients (12% and 0%; both p < 0.0001). These findings were not due to arousal frequency, as INS patients were more likely to have prolonged nightly awakenings (93%) than RLS patients (64%; p = 0.003). Among patients on sedative-hypnotics, amnestic SRED and sleepwalking were more common in the setting of RLS (80%) than INS (8%; p < 0.0001). Further, NE and SRED in RLS were not secondary to dopaminergic therapy, as RLS patients demonstrated a substantial drop (68% to 34%; p = 0.0026) in the frequency of NE after dopamine agents were initiated, and there were no cases of dopaminergic agents inducing novel NE or SRED.

CONCLUSION

NE is common in RLS and not due to frequent nocturnal awakenings or dopaminergic agents. Amnestic SRED occurs predominantly in the setting of RLS mistreatment with sedating agents. In light of previous reports, these findings suggest that nocturnal eating is a non-motor manifestation of RLS with several clinical implications discussed here.

Zolpidem ingestion, automatisms, and sleep driving: a clinical and legal case series

STUDY OBJECTIVES

To describe zolpidem-associated complex behaviors, including both daytime automatisms and sleep-related parasomnias.

METHODS

A case series of eight clinical patients and six legal defendants is presented. Patients presented to the author after an episode of confusion, amnesia, or somnambulism. Legal defendants were being prosecuted for driving under the influence, and the author reviewed the cases as expert witness for the defense. Potential predisposing factors including comorbidities, social situation, physician instruction, concomitant medications, and patterns of medication management were considered.

RESULTS

Patients and defendants exhibited abnormal behavior characterized by poor motor control and confusion. Although remaining apparently interactive with the environment, all reported amnesia for 3 to 5 hours. In some cases, the episodes began during daytime wakefulness because of accidental or purposeful ingestion of the zolpidem and are considered automatisms. Other cases began after ingestion of zolpidem at the time of going to bed and are considered parasomnias. Risk factors for both wake and sleep-related automatic complex behaviors include the concomitant ingestion of other sedating drugs, a higher dose of zolpidem, a history of parasomnia, ingestion at times other than bedtime or when sleep is unlikely, poor management of pill bottles, and living alone. In addition, similar size and shape of two medications contributed to accidental ingestion in at least one case.

CONCLUSIONS

Sleep driving and other complex behaviors can occur after zolpidem ingestion. Physicians should assess patients for potential risk factors and inquire about parasomnias. Serious legal and medical complications can occur as a result of these forms of automatic complex behaviors.

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.

Hypnotics' association with mortality or cancer: a matched cohort study

OBJECTIVES

An estimated 6%-10% of US adults took a hypnotic drug for poor sleep in 2010. This study extends previous reports associating hypnotics with excess mortality.

SETTING

A large integrated health system in the USA.

DESIGN

Longitudinal electronic medical records were extracted for a one-to-two matched cohort survival analysis.

SUBJECTS

Subjects (mean age 54 years) were 10 529 patients who received hypnotic prescriptions and 23 676 matched controls with no hypnotic prescriptions, followed for an average of 2.5 years between January 2002 and January 2007.

MAIN OUTCOME MEASURES

Data were adjusted for age, gender, smoking, body mass index, ethnicity, marital status, alcohol use and prior cancer. Hazard ratios (HRs) for death were computed from Cox proportional hazards models controlled for risk factors and using up to 116 strata, which exactly matched cases and controls by 12 classes of comorbidity.

RESULTS

As predicted, patients prescribed any hypnotic had substantially elevated hazards of dying compared to those prescribed no hypnotics. For groups prescribed 0.4-18, 18-132 and >132 doses/year, HRs (95% CIs) were 3.60 (2.92 to 4.44), 4.43 (3.67 to 5.36) and 5.32 (4.50 to 6.30), respectively, demonstrating a dose-response association. HRs were elevated in separate analyses for several common hypnotics, including zolpidem, temazepam, eszopiclone, zaleplon, other benzodiazepines, barbiturates and sedative antihistamines. Hypnotic use in the upper third was associated with a significant elevation of incident cancer; HR=1.35 (95% CI 1.18 to 1.55). Results were robust within groups suffering each comorbidity, indicating that the death and cancer hazards associated with hypnotic drugs were not attributable to pre-existing disease.

CONCLUSIONS

Receiving hypnotic prescriptions was associated with greater than threefold increased hazards of death even when prescribed <18 pills/year. This association held in separate analyses for several commonly used hypnotics and for newer shorter-acting drugs. Control of selective prescription of hypnotics for patients in poor health did not explain the observed excess mortality.

Sodium oxybate-induced sleep driving and sleep-related eating disorder

Hypnosedative-induced complex behaviors have gained increased attention in recent years as a potential complication of benzodiazepines and benzodiazepine-receptor agonist use. Sodium oxybate (SO), the sodium salt of γ-hydroxybutyrate, an inhibitory neurotransmitter, has been associated with dose-dependent rates of somnambulism; however, there is limited information about complex motor behaviors with SO. We describe a patient with narcolepsy-cataplexy who experienced one episode of sleep-driving and at least two sleep-related eating episodes with therapeutic doses of SO.

Risk of fractures requiring hospitalization after an initial prescription for zolpidem, alprazolam, lorazepam, or diazepam in older adults

OBJECTIVES

To determine whether zolpidem is a safer alternative to benzodiazepines.

DESIGN

Retrospective cohort study.

SETTING

Community based.

PARTICIPANTS

Health maintenance organization members with an initial prescription for zolpidem (n = 43,343), alprazolam (n = 103,790), lorazepam (n = 150,858), or diazepam (n = 93,618).

MEASUREMENTS

Zolpidem and benzodiazepine prescriptions were identified from pharmacy databases. Rates of nonvertebral fractures and hip fractures requiring hospitalization were compared before and after an initial prescription for each treatment, adjusting for confounders using doubly robust estimation.

RESULTS

In patients aged 65 and older, the rates of nonvertebral fractures and dislocations were similar in the pre- treatment intervals. The rate ratios (RRs) for the 90-day posttreatment interval relative to the pretreatment interval were 2.55 (95% confidence interval (CI) = 1.78-3.65; P < .001) for zolpidem, 1.14 (95% CI = 0.80-1.64; P = .42) for alprazolam, 1.53 (95% CI = 1.23-1.91; P < .001) for lorazepam, and 1.97 (95% CI = 1.22-3.18; P = .01) for diazepam. The ratio of RRs (RRR)-the RR in the posttreatment period adjusted for the corresponding RR in the pretreatment period-were 2.23 (95% CI = 1.36-3.66; P = .006) for zolpidem relative to alprazolam, 1.68 (95% CI = 1.12-2.53; P = .02) for zolpidem relative to lorazepam, and 1.29 (95% CI = 0.72-2.30; P = .32) for zolpidem relative to diazepam. The RRs decreased with time from the initial prescription (trend P < .001), as would be expected if the association is causal.

CONCLUSION

In older adults, the risk of injury with zolpidem exceeded that with alprazolam and lorazepam and was similar to that with diazepam. If the associations are causal, then the high incidence of these fractures implies that these treatment induce a substantial number of fractures and consequential costs. Further study of the association is imperative.

Prevalence and factors associated with off-label antidepressant prescriptions for insomnia

Background:

The primary objective of our study was to investigate the prevalence of off-label antidepressant drug use in insomnia. The secondary objective was to compare prescribing patterns between off-label antidepressants vs hypnotics approved by the US Food and Drug Administration for insomnia, with particular emphasis on socioeconomic characteristics of patients and physicians.

Methods:

We undertook a secondary data analysis using the national longitudinal database from the 2006 National Ambulatory Medical Care Survey. Subjects were identified from outpatient visits in which at least one insomnia drug was prescribed. A series of weighted Chi-squared statistics was used to compare drug use for insomnia across various patient and physician characteristics. Multivariate logistic regression was conducted to identify factors associated with off-label antidepressant drug use.

Results:

Among 901.95 million outpatient visits that took place in the US in 2006, an estimated 30.43 million visits included at least one drug prescription for insomnia. Off-label antidepressants were prescribed significantly more frequently (45.1%) than nonbenzodiazepine z-hypnotics (43.2%) and benzodiazepines (11.7%). Insomnia prescribing patterns were significantly influenced by physician specialty and physician office settings. Pediatricians (odds ratio [OR]: 65.892; 95% confidence interval [CI]: 5.536–810.564) and neurologists (OR: 4.784; 95% CI: 2.044–11.201) were more likely to prescribe off-label antidepressants than psychiatrists. Self-paying patients were more likely to receive off-label antidepressants as treatment for insomnia than patients with private insurance (OR 2.594; 95% CI: 1.128–5.967).

Conclusion:

Our findings indicate significant socioeconomic disparities in the use of off-label antidepressants. Future studies might explore interventional and educational strategies to ensure well informed clinical decisions that can withstand pharmaceutical marketing strategies and diagnostic uncertainties regarding the treatment of insomnia.

Desensitization of GABAergic receptors as a mechanism of zolpidem-induced somnambulism

Sleepwalking is a frequently reported side effect of zolpidem which is a short-acting hypnotic drug potentiating activity of GABA(A) receptors. Paradoxically, the most commonly used medications for somnambulism are benzodiazepines, especially clonazepam, which also potentiate activity of GABA(A) receptors. It is proposed that zolpidem-induced sleepwalking can be explained by the desensitization of GABAergic receptors located on serotonergic neurons. According to the proposed model, the delay between desensitization of GABA receptors and a compensatory decrease in serotonin release constitutes the time window for parasomnias. The occurrence of sleepwalking depends on individual differences in receptor desensitization, autoregulation of serotonin release and drug pharmacokinetics. The proposed mechanism of interaction between GABAergic and serotonergic systems can be also relevant for zolpidem abuse and zolpidem-induced hallucinations. It is therefore suggested that special care should be taken when zolpidem is used in patients taking at the same time selective serotonin reuptake inhibitors.

Sleepwalking, a possible side effect of antipsychotic medication

Two case examples and a review of the sleep literature illustrate the potential of antipsychotic medication to trigger sleepwalking episodes in the context of schizophrenia. Causative hypotheses are briefly reviewed, as well as risk factors, differential diagnosis, and management. Sleepwalking may contribute to delusions, aggression, and accidental suicide. It is important to investigate sleep disorders in schizophrenia. They are not rare and may contribute to behavior that increases the stigma and isolation of individuals with schizophrenia.

Good night and good luck: norepinephrine in sleep pharmacology

Sleep is a crucial biological process that is regulated through complex interactions between multiple brain regions and neuromodulators. As sleep disorders can have deleterious impacts on health and quality of life, a wide variety of pharmacotherapies have been developed to treat conditions of excessive wakefulness and excessive sleepiness. The neurotransmitter norepinephrine (NE), through its involvement in the ascending arousal system, impacts the efficacy of many wake- and sleep-promoting medications. Wake-promoting drugs such as amphetamine and modafinil increase extracellular levels of NE, enhancing transmission along the wake-promoting pathway. GABAergic sleep-promoting medications like benzodiazepines and benzodiazepine-like drugs that act more specifically on benzodiazepine receptors increase the activity of GABA, which inhibits NE transmission and the wake-promoting pathway. Melatonin and related compounds increase sleep by suppressing the activity of the neurons in the brain's circadian clock, and NE influences the synthesis of melatonin. Antihistamines block the wake-promoting effects of histamine, which shares reciprocal signaling with NE. Many antidepressants that affect the signaling of NE are also used for treatment of insomnia. Finally, adrenergic receptor antagonists that are used to treat cardiovascular disorders have considerable sedative effects. Therefore, NE, long known for its role in maintaining general arousal, is also a crucial player in sleep pharmacology. The purpose of this review is to consider the role of NE in the actions of wake- and sleep-promoting drugs within the framework of the brain arousal systems.

Zolpidem-induced sleep-related eating disorder

An association between zolpidem administration and sleep-related eating disorder (SRED) has been suggested. The authors observed zolpidem-induced SRED in restless legs syndrome (RLS). With the review of previous reports, we identified a common occurrence of RLS in zolpidem-induced SRED.

Parasomnias and movement disorders in children and adolescents

Childhood parasomnias and movement disorders arise from a variety of etiologic factors. For some children, psychopathology plays a causal role in sleep disorders; in other cases, recurrent parasomnia episodes induce psychopathology. Current research reveals complex interconnections between sleep and mental health. As such, it is important that clinicians consider the impact psychiatric disorders have on childhood parasomnias. This article describes common parasomnias and movement disorders in children and adolescents, with emphasis on psychologic and behavioral comorbidities.