“About 20 percent of adults in the United States report a level of daytime sleepiness sufficient to interfere with daily activities, and excessive daytime sleepiness is the leading symptom of patients presenting to sleep clinics,” writes J.F. Pagel, MD, MS, from Rocky Mountain Sleep Disorders Center in Pueblo, Colorado.

“The prevalence of excessive daytime sleepiness is highest in adolescents, older persons, and shift workers, but assessment of its true prevalence is difficult because of the subjective nature of the symptoms, inconsistencies in terminology, and a lack of consensus on methods of diagnosis and assessment,” Dr. Pagel writes. “Some persons use subjective terminology (e.g., drowsiness, languor, inertness, fatigue, sluggishness) when describing symptoms of excessive daytime sleepiness.”

Excessive daytime sleepiness is one of the most prevalent causes of sleep-related patient symptoms, affecting approximately 20% of the population. Persons with excessive daytime sleepiness generally have poorer health vs adults of similar age. The Stanford Sleepiness Scale and the Epworth Sleepiness Scale are useful tools to screen for excessive daytime sleepiness.

The consequences of excessive daytime sleepiness can be varied and sometimes serious or even fatal, largely because of increased risk for motor vehicle crashes and work-related injuries. Sleep problems contribute to more than 100,000 motor vehicle crashes, resulting in 71,000 personal injuries and 1500 deaths annually, with more than half of single-vehicle crashes involving heavy trucks being fatigue related. Adolescent and young adult male drivers are involved in most sleep-related crashes.

Sleep deprivation, obstructive sleep apnea (OSA), and sedating medications are the most common causes of excessive daytime sleepiness. Other potential causes may include certain medical and psychiatric conditions and sleep disorders, such as narcolepsy, periodic limb movement disorder, and restless legs syndrome. Neurologic causes include head trauma, stroke, brain tumors, encephalitis, and genetic and neurodegenerative conditions.

OSA is a frequent cause of excessive daytime sleepiness, as well as the potentially most dangerous and physiologically disruptive cause. Polysomnography should typically be used to confirm the diagnosis. In patients diagnosed with OSA, possible comorbid conditions of hypertension, diabetes, and coronary disease should be identified and managed. Current prevalence of the risk for, or presence of, OSA is estimated to be 26% to 32% of adults, but this is anticipated to increase.

Sedating medications that may cause excessive daytime sleepiness include alpha- and beta-adrenergic blockers, antiepileptic drugs such as hydantoins and succinimides, antidiarrheal agents, antiemetics, antihistamines, antimuscarinics and antispasmodics, antiparkinsonian agents, antipsychotics, cough suppressants, genitourinary smooth muscle relaxants, opiate agonists and partial opiate agonists, and skeletal muscle relaxants.

Antidepressant medications with sedating effects include monoamine oxidase inhibitors, tricyclics, and selective serotonin reuptake inhibitors. Sedative-hypnotics and anxiolytics include barbiturates, benzodiazepines, and other drugs acting on γ-aminobutyric acid receptors.

The cornerstone of evaluating and managing excessive daytime sleepiness is to identify and treat OSA and/or other underlying conditions. In some patients, the appropriate use of activating medications may be indicated.

Most patients with OSA will experience reduction in symptoms of daytime sleepiness when treated with positive pressure devices, such as continuous positive airway pressure (CPAP) during sleep. There is less evidence supporting effects of medications, dental appliances, surgery, and other treatments of OSA.

For the treatment of excessive daytime sleepiness, modafinil is considered to be the first-line choice of activating agent because of its generally benign adverse effect profile. Because it is pharmacologically distinct from the amphetamines, it has a much lower potential for abuse (schedule IV). In addition to its indication for the treatment of persistent sleepiness associated with OSA in patients already being treated with CPAP, modafinil is also indicated for the treatment of daytime sleepiness in patients with shift work disorder.

As schedule II prescription drugs, the amphetamines are thought to have a high potential for abuse and must therefore be used with caution to promote alertness in sleepy patients. These include dextroamphetamine, methylphenidate, and pemoline. Personality changes, tremor, hypertension, headaches, and gastroesophageal reflux may be associated with amphetamine use.

“The use of activating agents is inappropriate in hypersomnolent patients with untreated OSA — although daytime sleepiness may be improved with these agents, the patient remains at risk from the pathophysiologic consequences of untreated OSA,” Dr. Pagel writes.

Specific clinical recommendations for practice, all rated level of evidence B, are as follows:

• Treating patients who have OSA with CPAP therapy is associated with decreased daytime sleepiness and a reduced risk for motor vehicle crashes.
• In patients with OSA who are already being treated with CPAP, modafinil therapy has been associated with reduction in symptoms of persistent sleepiness. Modafinil also appears to reduce daytime sleepiness in patients with shift work disorder.

“The physician treating patients with excessive daytime sleepiness (or patients using drugs likely to affect driving performance) has the responsibility to make a clinical assessment of the patient’s overall risk of unsafe driving, and to document driving recommendations and precautions,” Dr. Pagel concludes. “A physician should report patients who fail to comply with treatment, particularly high-risk persons such as airline pilots, truck, bus, and occupational drivers, and those with a history of recent sleepiness-associated incidents.”

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