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Management of Shift Work Sleep Disorder: Alice in Wonderland Redux?

2004; Lippincott Williams & Wilkins; Volume: 46; Issue: 10 Linguagem: Inglês

10.1097/01.jom.0000141654.55478.61

1536-5948

Bruce W. Sherman, Kingman P. Strohl,

Advanced Glycation End Products research

Shift work sleep disorder (SWSD) is a recognized clinical entity, occurring among employees typically working night or early morning shifts on either a fixed or rotation schedule. SWSD is characterized by fatigue and functional impairment and is accompanied by objective and subjective sleepiness. Affected individuals also have difficulties with sleep initiation and maintenance that are not readily corrected by behavioral changes intended to optimize sleep duration and quality. The long-term health impact of SWSD is not known, but as a whole, associations are present among shift work and an increased incidence of heart disease, gastrointestinal disease, and diabetes1 as well as breast and colorectal cancer.2,3 Additionally, the incidence of work-related injury is greater among shift workers,4 particularly likely for those with SWSD. Although a common definition of SWSD has yet to be formulated, the disorder is estimated to occur in approximately 8% to 24% of night or rotating shift workers (T. Akerstedt, unpublished data). The long-term effects of SWSD are currently unknown, including the circumstance of remission once shift work has ceased. Pharmacotherapy is available for treatment of symptomatic sleepiness. Caffeine will sustain performance and alertness in the face of sleep deprivation.5 However, unacceptable acute side effects, including tremor, gastrointestinal symptoms, and palpitations, have limited its role as an effective alerting agent. Chronic use of caffeine can produce tolerance, mood disorders, and insomnia, and acute withdrawal is associated with sleepiness. However, a recent report demonstrated that hourly, low-dose caffeine acts to delay performance decline during extended wakefulness.6 Whether this strategy of caffeine use is applicable to chronic shift work or in the management of SWSD remains to be determined. Modafinil is a wake-promoting medication with demonstrated efficacy in improving alertness, vigilance, and cognitive function with acute sleep deprivation.7 Although its specific mode of action is unknown, it has an acceptable safety profile and has recently received approval from the Food and Drug Administration for symptomatic treatment of sleepiness caused by SWSD.8 Abuse potential is low, and gastrointestinal side-effects are dose-related and transient.9 However, as demonstrated for some performance and alertness measures in sleep-deprived young, healthy adults, modafinil offers little advantage over caffeine.5 Although alerting agents have demonstrated effectiveness in the management of waketime sleepiness, sleep-promoting medications also may have a role. Insomnia as the result of an out-of-phase endogenous circadian rhythm and environmental stimuli that disrupt sleep may respond well to drugs that induce and maintain sleep. Historically, benzodiazepines have been a frequently used medication class, but concerns regarding a residual “hangover” with impaired performance after awakening have limited use, particularly for employees whose performance is critical for personal or public safety.10 A more recently approved sleep-promoting medication, zaleplon, appears to have less of a “hangover” effect,11 but concerns persist related to the potential for workplace performance impairment12 and to resulting liability have limited providers’ willingness to prescribe these agents. Eszopiclone and indiplon are new medications not yet approved by the Food and Drug Administration that have a relatively longer duration of action, in addition to the reported absence of any significant residual effect.13 Although still investigational, these medications hold significant promise for more effective management of insomnia, possibly including that caused by SWSD. …and round the neck of the bottle was a paper label, with the words ‘DRINK ME’ beautifully printed on it in large letters. It was all very well to say ‘DRINK ME,’ but the wise little Alice was not going to do that in a hurry. ‘No, I’ll look first,’ she said, ‘and see whether it’s marked “poison” or not’… …she opened it, and found in it a very small cake, on which the words ‘EAT ME’ were beautifully marked in currants. ‘Well, I’ll eat it,’ said Alice, ‘and if it makes me grow larger, I can reach the key… ’ Lewis Carroll, Alice in Wonderland How does this relate to Alice in Wonderland? Like Alice, who could consume a drink to make her smaller or cake to make her taller, individuals will soon have the potential to use one medication type to promote alertness and the other to facilitate sleep. Increasing awareness of SWSD as the result of both direct-to-consumer information about these medications and the anticipated publication of the findings from a recent National Sleep Foundation conference on SWSD will likely prompt increased use of pharmacotherapy for this condition. Both the sleep-promoting and wake-promoting medications are likely important components of the management of SWSD, but appropriate use of these medications is critical. Otherwise, they can potentially represent ‘poison’ in the form of inappropriate and potentially harmful treatment. There is the potential for symptomatic treatment of sleepiness to mask an underlying disorder, such as sleep apnea. Prior to initiating pharmacotherapy for sleep-related symptoms, a detailed sleep history will help to better focus further diagnostic and therapeutic interventions. As well, the long-term impact of these medications on the health problems associated with shift work is unknown. Further, in individuals with sleep disorders, information regarding the long-term effect of wake-promoting medications is lacking. For example, there is evidence that individuals with obstructive sleep apnea may decrease their use of CPAP when using modafinil,14 raising concern that the medication could compromise the use of specific or more directed therapy. On the surface, pharmacotherapy for SWSD may represent a simple solution, but it is essential to first address the many behavior-related factors that can help to control symptoms. These include implementing a more effective sleep/nap strategy, using light/dark environmental changes to better manage the circadian misalignment, and minimizing stimulants during the hours before sleep. Clinicians can provide support for restriction or elimination of unhealthy lifestyle behaviors, including alcohol, caffeine (before bedtime) and cigarettes, as well as for general health recommendations of regular exercise and a proper diet.15 Thus, medication therapy should be complemented by information and goal setting designed to reduce social/domestic tensions and enhance behaviors that improve sleep quality. Collectively, this approach to “sleep hygiene” can reduce medication need or enhance its effect.15 As symptomatic sleepiness in a shift worker from any cause will likely respond to pharmacotherapy, it is essential that other underlying causes be considered. Clearly the most common is obstructive sleep apnea, with a reported prevalence of 4% to 10% in the adult population, with 75% to 80% remaining undiagnosed.16 Given that the prevalence of sleep apnea and its major risk factor (obesity) is comparable with that estimated for SWSD, and that some patients with sleep apnea complain of insomnia and fatigue rather than sleepiness, this diagnosis bears careful consideration. Other etiologies of sleepiness and insomnia include restless leg syndrome, primary hypersomnolence, narcolepsy, delayed or advanced sleep phase syndrome, and insufficient sleep due to mood disorders. Importantly, if an individual has persistent symptoms following resumption of a more normal sleep-wake cycle, a diagnosis other than SWSD should be considered. Accurate diagnosis may result in more effective treatment directed at the underlying cause, rather than symptom control. The foundation of both diagnosis and management is the sleep history, with particular attention to those factors that explicitly or implicitly impair alertness, or impact upon sleep/wake cycles. Often the employee is not aware of the need to have adequate sleep, to organize his/her life off shift for sleep needs, or to create a bedroom environment so that sleep is not interrupted by light, noise, excessive heat, or intrusions (telephone, gas meter readings, dog barking, lawn services etc.) that go unnoticed by those who work during the day. In addition, family and friends often underestimate the need for sleep in the shift worker. A thorough review of symptoms, medical conditions, medications, drugs, alcohol and tobacco use is needed to adequately understand those behaviors and physical factors that might impede sleep or reduce alertness. In some instances identification and management of these factors can significantly improve a worker’s performance and reduce symptoms of SWSD even in the presence of other sleep problems or disorders. It is important that employees experiencing symptoms of SWSD are provided with a clear understanding of their condition and available treatment options, including behavioral changes, pharmacotherapy or employment change. With insight into the benefits, shortcomings, and expected outcome of each option, individuals can then make an informed decision regarding their most appropriate course of action. Once the diagnosis of SWSD and its treatment appears in the popular press, an increase in the diagnosis as well as requests for accommodation may occur. Physicians may recommend that symptomatic individuals be removed from night shift or shift work rotation. Other employees may also seek to use complaints of sleepiness as a medical justification for work schedule change. If a physician recommends restriction against night shift or shift rotation, continued employment for the individual may be at risk if no alternative work schedule is available. It is therefore important for the treating physician to incorporate an understanding of patient employment concerns as a part of their management plan. Importantly, court rulings indicate that the Americans with Disabilities Act legislation does not appear to afford protection for affected individuals, because SWSD, although a medical diagnosis, has not been deemed a disability.17,18 Recent developments in the study of sleep deprivation have contributed to a better understanding of SWSD. There appear to be consistent, inter-individual differences in neurobehavioral impairment because of sleep deprivation.19 These findings may help to explain why some individuals are likely to experience more significant symptoms during shift work. If an individual can be proactively identified as at risk for SWSD, the associated safety concerns can be ameliorated with an appropriate work schedule. Given the available clinical research information about awake-promoting and sleep-promoting and maintaining medications, what is needed is a better understanding of the impact of these medications on employees with SWSD. With two medications—modafinil and caffeine—available at considerably different cost, it is important to understand when each is most appropriately used. From the employer’s perspective, the outcome measures should include improved vigilance, consistent work quality, and fewer errors and accidents during work. For the employee, measurable outcomes should include a decreased risk of heart disease, glucose intolerance, obesity, and commuting accidents. Ongoing research is underway to better understand this condition, including consensus on diagnostic criteria and management goals. A review of the diagnostic features, pathogenesis and treatment options available for affected individuals is forthcoming from the recent National Sleep Foundation conference on SWSD. With corporations increasing their focus on maximizing productivity with a limited workforce size, recognition and care for employees with SWSD may well become a commonplace event.