Recognition and management of excessive sleepiness in the primary care setting

BACKGROUND

Excessive sleepiness often goes unrecognized in the primary care setting despite its high prevalence and deleterious effects on both individual and public safety. Patients with neurologic and psychiatric illnesses, as well as those with acute and chronic medical conditions, plus those with sleep disorders, often have symptoms of excessive sleepiness, tiredness, and fatigue. Recognition and prompt treatment of these symptoms are important, even though their etiology may not be immediately understood. This review focuses on the underlying causes, consequences, identification, and treatment of excessive sleepiness.

DATA SOURCES

A search of the literature to 2007 was performed using the PubMed search engine. English-language articles were identified using the following search terms: excessive sleepiness, fatigue, circadian rhythm, obstructive sleep apnea, shift work disorder, narcolepsy, drowsy driving, and wakefulness. Additional references were identified through bibliography reviews of relevant articles.

DATA SYNTHESIS

Current assessments of the prevalence, consequences, and etiologies of excessive sleepiness, with leading treatment strategies, were extracted, reviewed, and summarized to meet the objectives of this article.

CONCLUSIONS

Excessive sleepiness is associated with a wide range of medical, neurologic, and psychiatric disorders frequently seen in primary care practice. Excessive sleepiness is a serious, debilitating, potentially life-threatening condition, yet also treatable, and it is important to initiate appropriate intervention as early as possible. Physicians should place increasing emphasis on the substantial benefits that accompany improvements in wakefulness.

Tolerability and efficacy of armodafinil in naïve patients with excessive sleepiness associated with obstructive sleep apnea, shift work disorder, or narcolepsy: a 12-month, open-label, flexible-dose study with an extension period

STUDY OBJECTIVES

This 12-month, open-label, flexible-dose study with an extension period evaluated the tolerability and efficacy of armodafinil in patients with excessive sleepiness associated with treated obstructive sleep apnea (OSA), shift work disorder (SWD), or narcolepsy.

METHODS

Armodafinil-naïve, adult patients with excessive sleepiness associated with treated OSA (n = 170), SWD (n = 108), or narcolepsy (n = 50) received armodafinil (100-250 mg) once daily (treated OSA or narcolepsy) or before night shifts (SWD). Patients with OSA were regular users of continuous positive airway pressure (CPAP) therapy. Efficacy measures included the Clinical Global Impression of Improvement (CGI-I) and the Epworth Sleepiness Scale (ESS).

RESULTS

Across the diagnosis groups, the most commonly occurring adverse event was headache (14%-24%). Forty-three patients (13%) and 13 patients (4%) were withdrawn because of adverse events and insufficient efficacy, respectively. Armodafinil did not adversely affect CPAP therapy. At the final visit, 80% (95% CI: 74.1, 86.7) of patients with treated OSA and 84% (72.7, 94.8) of patients with narcolepsy were rated on the CGI-I as at least minimally improved with regard to overall clinical condition; 98% (95.2, 100.0) of patients with SWD were rated as improved with regard to sleepiness during night shifts, including the commute to and from work. Armodafinil improved ESS total scores in patients with treated OSA (mean [SD] [95% CI] change from baseline, -7.3 [5.6] [-8.39, -6.30]) and patients with narcolepsy (-4.7 [6.0] [-7.41, -1.93]).

CONCLUSIONS

Armodafinil administered for 12 months or more was generally well tolerated and improved wakefulness in patients with excessive sleepiness associated with treated OSA, SWD, or narcolepsy. Armodafinil improved the overall clinical condition of patients with treated OSA or narcolepsy.

Neurophysiology of sleep and wakefulness: basic science and clinical implications

Increased attention to the prevalence of excessive sleepiness has led to a clear need to treat this symptom, thus reinforcing the need for a greater understanding of the neurobiology of sleep and wakefulness. Although the physiological mechanisms of sleep and wakefulness are highly interrelated, recent research reveals that there are distinct differences in the active brain processing and the specific neurochemical systems involved in the two states. In this review, we will examine the specific neuronal pathways, transmitters, and receptors composing the ascending arousal system that flow from the brainstem through the thalamus, hypothalamus, and basal forebrain to the cerebral cortex. We will also discuss the mutually inhibitory interaction between the core neuronal components of this arousal system and the sleep-active neurons in the ventrolateral preoptic nucleus, which serves as a brainstem-switch, regulating the stability of the sleep-wake states. In addition, we will review the role of homeostatic and circadian processes in the sleep-wake cycle, including the influence of the suprachiasmatic nucleus on coordination of sleep-wake systems. Finally, we will summarize how the above processes are reflected in disorders of sleep and wakefulness, including insomnia, narcolepsy, disorders associated with fragmented sleep, circadian rhythm sleep disorders, and primary neurological disorders such as Parkinson’s and Alzheimer’s diseases.

Modafinil in the treatment of excessive sleepiness

The wake-promoting agent modafinil is approved for the treatment of excessive sleepiness associated with obstructive sleep apnea (OSA), shift work disorder (SWD), and narcolepsy. In OSA, modafinil is recommended for use as an adjunct to standard therapies that treat the underlying airway obstruction. This article reviews the literature on modafinil (pharmacology, pharmacokinetics, efficacy, tolerability, and abuse potential), with emphasis on use of modafinil in the treatment of excessive sleepiness in patients with OSA, SWD, and narcolepsy. In large-scale, double-blind, placebo-controlled studies, modafinil improved objectively determined sleep latency, improved overall clinical condition related to severity of sleepiness, and reduced patient-reported sleepiness. Improvements in wakefulness were accompanied by improvements in behavioral alertness, functional status, and health-related quality of life. In patients with SWD, diary data showed modafinil reduced the maximum level of sleepiness during night shift work, level of sleepiness during the commute home, and incidence of accidents or near-accidents during the commute home when compared with placebo. Modafinil was well tolerated, without adversely affecting cardiovascular parameters or scheduled sleep. These findings and those of extension studies which reported improvements were maintained suggest modafinil has a beneficial effect on daily life and well-being in patients with excessive sleepiness associated with OSA, SWD, or narcolepsy.

Evaluation of the safety of modafinil for treatment of excessive sleepiness

STUDY OBJECTIVES

Modafinil is a wake-promoting agent shown to improve wakefulness in patients with excessive sleepiness (hypersomnolence) associated with shift work sleep disorder, obstructive sleep apnea, or narcolepsy. Safety and tolerability data from 6 randomized, double-blind, placebo-controlled studies were combined to evaluate modafinil across these different patient populations.

METHODS

One thousand five hundred twenty-nine outpatients received modafinil 200, 300, or 400 mg or placebo once daily for up to 12 weeks. Assessments included recording of adverse events and effects of modafinil on blood pressure/heart rate, electrocardiogram intervals, polysomnography, and clinical laboratory parameters.

RESULTS

Two hundred seventy-three patients with shift work sleep disorder, 292 with obstructive sleep apnea, and 369 with narcolepsy received modafinil; 567 received placebo. Modafinil was well tolerated versus placebo, with headache (34% vs 23%, respectively), nausea (11% vs 3%), and infection (10% vs 12%) the most common adverse events. Adverse events were similar across all patient groups. Twenty-seven serious adverse events were reported (modafinil, n = 18; placebo, n = 9). In modafinil-treated patients, clinically significant increases in diastolic or systolic blood pressure were infrequent (n = 9 and n = 1, respectively, < 1% of patients). In the studies, 1 patient in the modafinil group and 1 in the placebo group had a clinically significant increase in heart rate. New clinically meaningful electrocardiogram abnormalities were rare with modafinil (n = 2) and placebo (n = 4). Clinically significant abnormalities in mean laboratory parameters were observed in fewer than 1% of modafinil-treated patients at final visit. Modafinil did not affect sleep architecture in any patient population according to polysomnography.

CONCLUSIONS

Modafinil is well tolerated in the treatment of excessive sleepiness associated with disorders of sleep and wakefulness and does not affect cardiovascular or sleep parameters.

Modafinil: new indications for wake promotion

In January 2004, the wake-promoting agent, modafinil, was approved in the US for the treatment of excessive sleepiness (ES) associated with obstructive sleep apnoea/hypopnoea syndrome (OSAHS) and shift-work sleep disorder (SWSD), representing an expansion of its labelling from the initial indication for ES associated with narcolepsy. A total of five randomised, placebo-controlled studies in these three disorders showed statistically significant benefits on various objective measures and subjective estimates of ES, including the Multiple Sleep Latency Test, Maintenance of Wakefulness Test, Epworth Sleepiness Scale and Karolinska Sleepiness Scale. Significant improvement was also seen in overall clinical condition (on the Clinical Global Impression of Change) and measures of sustained attention and reaction time (on the Psychomotor Vigilance Task). The clinical efficacy of modafinil, combined with improved safety over CNS stimulants, has made it the most prescribed medication for the treatment of ES associated with narcolepsy. Modafinil is the only medication approved for ES associated with OSAHS and SWSD (for OSAHS, it is indicated as an adjunct to standard treatments for the under-lying obstruction). Unlike many other medications used for ES, modafinil is not known to be abused. The most common adverse event reported in clinical studies was headaches; most were transient and mild-to-moderate in severity. Modafinil also has the potential for interactions with other drugs metabolised via cytochrome P450 enzyme pathways. Potential obstacles to the use of modafinil include an under-recognition of ES and its consequences. Increased education, both of the public and the medical community, should improve the recognition and therapy of ES.

Shift Work Sleep Disorder

More than 6 million Americans work night shifts on a regular or rotating basis. The negative consequences of shift work have been established, and recent evidence suggests that patients with shift work sleep disorder (SWSD) are at increased risk of these consequences and co-morbidities. SWSD is a relatively common but under-recognised, and hence undertreated, condition with potentially serious medical, social, economic and quality-of-life consequences. In addition to increased risk of gastrointestinal and cardiovascular disease, patients with SWSD experience clinically significant excessive sleepiness or insomnia associated with work during normal sleep times, which has important safety implications. A number of studies have evaluated countermeasures or interventions in shift workers; proposed treatments include chronobiotic interventions, such as light exposure, melatonin, hypnotic agents, caffeine and CNS stimulants (amphetamine), and the wake-promoting agents modafinil and armodafinil. However, most studies evaluating pharmacological therapies and nonpharmacological interventions simulate night-shift work under conditions that may not accurately reflect real-world activities. Pharmacological and nonpharmacological countermeasures evaluated mostly in simulated laboratory conditions have been shown to improve alertness or sleep in shift workers but have not yet been evaluated in patients with SWSD. To date, three randomised, double-blind clinical studies have evaluated pharmacological therapies in patients with SWSD. These studies showed that modafinil and armodafinil significantly improve the ability to sustain wakefulness during waking activities (e.g. working, driving), overall clinical condition, and sustained attention or memory in patients with SWSD. In conclusion, SWSD is a common condition that remains under-recognised and undertreated. Further research is needed to evaluate different treatment approaches for this condition, to clarify the substantial health and economic consequences of SWSD, and to determine the potential for interventions or treatments to reduce the negative consequences of this condition.

Dose effects of modafinil in sustaining wakefulness in narcolepsy patients with residual evening sleepiness

Excessive sleepiness associated with narcolepsy lasts throughout the waking day. The authors conducted two randomized, double-blind studies to compare the efficacy of modafinil once-daily versus split doses in maintaining wakefulness throughout the day. Fifty-six patients received modafinil. The split-dose regimens were significantly more effective than the 200-mg once-daily regimen for sustaining wakefulness in the late afternoon/evening. All modafinil dosing regimens were well tolerated. In patients who experience excessive sleepiness in the late afternoon/evening, despite satisfactory treatment earlier in the day, a split dose of modafinil may promote wakefulness throughout the waking day.

Modafinil for excessive sleepiness associated with shift-work sleep disorder

BACKGROUND

Patients with shift-work sleep disorder chronically have excessive sleepiness during night work and insomnia when attempting to sleep during the day. We evaluated the use of modafinil for treating sleepiness in patients with this disorder.

METHODS

In a three-month, double-blind trial, we randomly assigned 209 patients with shift-work sleep disorder to receive either 200 mg of modafinil or placebo before the start of each shift. Assessments were performed with the use of the nighttime Multiple Sleep Latency Test, the Clinical Global Impression of Change, the Psychomotor Vigilance Test, diaries of patients, and daytime polysomnography. After randomization, we conducted monthly assessments.

RESULTS

Treatment with modafinil, as compared with placebo, resulted in a modest improvement from baseline in mean (+/-SEM) nighttime sleep latency (the interval between the time a person attempts to fall asleep and the onset of sleep) (1.7+/-0.4 vs. 0.3+/-0.3 minutes, respectively; P=0.002), and more patients had improvement in their clinical symptoms (74 percent vs. 36 percent, respectively; P<0.001). Patients who were receiving modafinil also had a reduction in the frequency and duration of lapses of attention during nighttime testing of their performance on the Psychomotor Vigilance Test (change from baseline, a reduction in lapse frequency of 2.6 vs. an increase of 3.8, respectively; P<0.001), and proportionally fewer patients reported having had accidents or near accidents while commuting home (29 percent vs. 54 percent, respectively; P<0.001). Despite these benefits, patients treated with modafinil continued to have excessive sleepiness and impaired performance at night. Modafinil did not adversely affect daytime sleep as compared with placebo. Headache was the most common adverse event.

CONCLUSIONS

Treatment with 200 mg of modafinil reduced the extreme sleepiness that we observed in patients with shift-work sleep disorder and resulted in a small but significant improvement in performance as compared with placebo. However, the residual sleepiness that was observed in the treated patients underscores the need for the development of interventions that are even more effective.

Pharmacologic management of daytime sleepiness

Excessive daytime sleepiness and abnormal sleep-wake patterns are becoming increasingly pervasive in modern society. The major causes of excessive daytime sleepiness include pathologic abnormalities of the central nervous system, such as narcolepsy and idiopathic hypersomnia; deficiencies in quality or quantity of sleep, such as those caused by sleep apnea and poor sleep hygiene; disturbances to the body's natural circadian rhythm, such as those caused by shift work or jet lag; and drugs, which can increase sleepiness either therapeutically or as a side effect. Determining the cause of daytime sleepiness is the first step in treating it. Setting appropriate and realistic treatment goals with the patient and initiating treatment are the next steps. Although the medications available to improve daytime wakefulness (e.g., amphetamines, methylphenidate, pemoline, and modafinil) are effective, they are not a substitute for sleep. Finally, timely follow-up is necessary to monitor treatment adherence, response, and side effects.

Effects of modafinil on wakefulness and executive function in patients with narcolepsy experiencing late-day sleepiness

OBJECTIVES

A modafinil daily dosing strategy promotes wakefulness in narcolepsy patients experiencing excessive daytime sleepiness; however, some patients may continue to experience late-day sleepiness. Excessive sleepiness in narcolepsy is associated with cognitive impairment. Modafinil has improved executive function in other models of excessive sleepiness. This study evaluated the effects of once-daily vs. split doses of modafinil on wakefulness and of combined doses on executive function in narcolepsy patients experiencing late-day sleepiness despite satisfactory modafinil treatment earlier in the day.

METHODS

After a 2-week washout, 24 patients received 3 weeks of double-blind treatment with modafinil 400-mg once daily (7 AM) plus placebo (noon) or modafinil 600-mg split dose (400 mg, 7 AM; 200 mg, noon). Assessments included a Maintenance of Wakefulness Test (MWT) for individual regimens and the Wisconsin Card Sort Test (WCST) for treatments combined.

RESULTS

Modafinil 600-mg split dose was significantly more effective than modafinil 400-mg once daily in improving late-day MWT scores (5 PM-7 PM; P < 0.05). Significant mean (+/- SEM) reductions from baseline of 8.2 +/- 2.7 in the total number of errors and 5.9 +/- 1.9 in total percent of errors (P < 0.05, both) were demonstrated for modafinil on the WCST. Modafinil was well tolerated; adverse events included headache (n = 1), emotional lability (n = 1), bronchitis (n = 1), and accidental injury (n = 2), with no reports of insomnia.

CONCLUSIONS

For patients with residual late-day sleepiness associated with narcolepsy, an additional 200-mg dose of modafinil taken at midday was effective in sustaining wakefulness throughout the entire waking day. Treatment with modafinil also significantly improved executive function.

Modafinil as adjunct therapy for daytime sleepiness in obstructive sleep apnea: a 12-week, open-label study

STUDY OBJECTIVES

The purpose of this 12-week study was to evaluate the efficacy and safety of adjunct modafinil to treat excessive sleepiness in patients with obstructive sleep apnea (OSA) who experience residual sleepiness despite regular nasal continuous positive airway pressure (nCPAP) use.

DESIGN

Twelve-week, open-label trial.

SETTING

Twenty-two centers in the United States.

PATIENTS

We studied 125 patients with moderate-to-severe OSA (ie, respiratory disturbance index > or =15) before nCPAP therapy and residual daytime sleepiness (Epworth sleepiness scale [ESS] score > or =10) despite effective and regular nCPAP therapy. Patients were studied after completing a 4-week, double-blind, placebo-controlled trial of nCPAP plus modafinil for the treatment of residual daytime sleepiness.

INTERVENTIONS AND MEASUREMENTS

Patients received individually titrated doses of modafinil (200 to 400 mg qd). Sleepiness was assessed using the ESS, quality of life was evaluated using the Functional Outcomes of Sleep Questionnaire (FOSQ), and the overall clinical effect was indexed using the clinical global impression of change scale. Adverse events, nCPAP use, and vital sign measurements were also recorded.

RESULTS

The significant improvements in daytime wakefulness and sleep-related functional status observed with modafinil treatment during the 4-week, double-blind study were maintained throughout 12 weeks of open-label treatment: week 12 ESS, 7.8 (4.7) vs 14.4 (3.1) at double-blind baseline; week 12 FOSQ, 3.3 (0.6) vs 14.4 (2.7) at double-blind baseline (mean [SD]). The percentage of patients rated as clinically improved increased from 83% after 1 week to > or =93% after 2 to 12 weeks of open-label treatment. Mean (SD) nCPAP use decreased from 6.3 (1.3) h/night at baseline to 5.9 (1.4) h/night (p = 0.004) during open-label treatment. The most common adverse events were headache (28%), anxiety (16%), and nervousness (14%).

CONCLUSIONS

Modafinil remained effective and well tolerated as an adjunct therapy for residual daytime sleepiness even after 12 weeks of daily dosing in patients with OSA receiving nCPAP therapy.

Efficacy and safety of modafinil for improving daytime wakefulness in patients treated previously with psychostimulants

OBJECTIVES

To assess the efficacy and safety of modafinil for improving wakefulness in narcolepsy patients treated previously with psychostimulants.

BACKGROUND

Modafinil has become a standard therapy for improving daytime wakefulness in narcolepsy patients and may be a useful therapeutic alternative to psychostimulants used to improve waking function in other medical conditions. Modafinil is chemically dissimilar to and has a pharmacological profile that differs from the psychostimulants. Modafinil has a low abuse potential and is well tolerated.

METHODS

Patients (N=151) with narcolepsy who had been unsatisfactorily treated with dextroamphetamine (N=48), methylphenidate (N=66), or pemoline (N=37) were enrolled in this 6-week, open-label, multicenter study. Following a 2-week washout period, patients received modafinil once daily (Week 1, 200 mg; Weeks 2-6, 200 or 400 mg). Efficacy was evaluated at Weeks 1, 2, and 6 using the Epworth Sleepiness Scale and the Clinical Global Impression of Change. Adverse events were monitored throughout the study.

RESULTS

Treatment with modafinil improved daytime wakefulness versus baseline regardless of which psychostimulant was taken previously. Mean ESS scores were improved after 1 week of treatment with modafinil. Improvements were maintained throughout the 6 weeks of treatment (all P<0.001 versus baseline after washout). At Week 6, 79% of all patients were considered to be clinically improved relative to post-washout baseline. The most frequent adverse events were headache, nausea, and insomnia; the majority of adverse events were mild or moderate in nature. Approximately 70% of patients were receiving 400 mg of modafinil once daily at the end of the study.

CONCLUSION

During this 6-week, open-label study, modafinil was an effective and well-tolerated treatment for improving daytime wakefulness in narcolepsy patients previously treated with psychostimulants.

Effect of modafinil on fatigue, mood, and health-related quality of life in patients with narcolepsy

INTRODUCTION

In addition to excessive sleepiness, patients with narcolepsy often have significant fatigue, depressed mood, and decreased quality of life.

OBJECTIVE

To determine whether treatment with modafinil for excessive sleepiness improves fatigue, mood, and health-related quality of life (HRQOL) in patients with narcolepsy.

MATERIALS AND METHODS

Outpatients with narcolepsy underwent a 14-day washout of psychostimulants and then were enrolled in this 6-week, open-label, multicenter study. Patients received modafinil starting at 200 mg once daily for week 1, and then 200 or 400 mg daily for weeks 2 through 6. Efficacy was evaluated using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Profile of Mood States (POMS). Safety was assessed by monitoring adverse events (AE).

RESULTS

At baseline, 151 patients had moderate to severe excessive sleepiness (mean Epworth Sleepiness Scale score=17.8+/-4.4). Most patients (> or =70% of 123 who completed the study) received 400 mg modafinil once daily during weeks 2 through 6. Modafinil significantly improved HRQOL, based on SF-36 measures of mental and physical component summary scores and subdomain scores of role-physical, social functioning, and vitality (each P<0.001). Modafinil treatment was also associated with significantly reduced fatigue and significantly improved vigor and cognition as assessed by the POMS (each P<0.001) from weeks 1 through 6. The most frequent AE with modafinil treatment were headache, nausea, and insomnia; most AE were mild or moderate in nature. Only seven patients (5%) withdrew from the study because of AE.

CONCLUSION

In narcolepsy patients who were switched from psychostimulants, modafinil therapy improved HRQOL and subjective feelings of vigor and cognitive functioning and reduced fatigue.

Dosing regimen effects of modafinil for improving daytime wakefulness in patients with narcolepsy

In a multicenter, randomized, double-blind study the authors compared the efficacy of modafinil 400 mg once daily, 400 mg given in a split dose, or 200 mg once daily for maintaining wakefulness throughout the day in patients (N = 32) with narcolepsy reporting a positive daytime response to modafinil but late-afternoon/evening sleepiness. Efficacy evaluations included an extended Maintenance of Wakefulness Test (9:00 am to 9:00 pm), the Clinical Global Impression of Change scale, and the Epworth Sleepiness Scale. Modafinil demonstrated significant improvement in wakefulness as assessed by the Epworth Sleepiness Scale compared with placebo at baseline (all P < 0.001). Modafinil significantly improved patients' ability to sustain wakefulness, as demonstrated by mean sleep latency at week 3 compared with placebo at baseline (all P < 0.001). The 400-mg split-dose regimen improved wakefulness significantly in the evening compared with the 200-mg and 400-mg once-daily regimen (both P < 0.05). The percentage of patients rated as "much improved" or "very much improved" with respect to evening sleepiness was 27%, 82%, and 80% in the 200-mg, 400-mg once-daily, and 400-mg split-dose groups, respectively. Adverse events were mild to moderate in nature and included headache, nausea, nervousness, dyspepsia, pain, and vomiting (all 6%). Some patients may benefit from 400-mg doses of modafinil taken once daily compared with 200-mg doses. A split-dose 400-mg regimen may be superior to once-daily dosing for sustaining wakefulness throughout the entire waking day.

Initiating treatment with modafinil for control of excessive daytime sleepiness in patients switching from methylphenidate: an open-label safety study assessing three strategies

RATIONALE

Modafinil is a first-line wake-promoting medication and a useful therapeutic alternative to psychostimulant medications for excessive daytime sleepiness.

OBJECTIVE

This 5-week, randomized, open-label study evaluated three strategies for switching patients from methylphenidate, a commonly used psychostimulant, to modafinil.

METHODS

Patients ( n=40) with excessive daytime sleepiness related to narcolepsy, who had received previous treatment with methylphenidate, were switched from methylphenidate to modafinil (200 mg/day followed by 400 mg/day) without a washout period between treatments, with a 2-day washout period between treatments, or by using a taper-down/titrate-up protocol. Adverse events were recorded throughout the study, and Epworth Sleepiness Scale scores were determined at the end of the study.

RESULTS

The majority of patients (95%) were successfully switched to modafinil. At the study end point, mean Epworth Sleepiness Scale scores were <12 for each treatment group. All three switching strategies were well tolerated, with adverse events mild or moderate in nature. Adverse events most frequently reported during modafinil treatment were among those seen previously in large-scale, placebo-controlled studies. There were no meaningful differences among the treatment groups in the frequency or severity of adverse events or in their relationship to modafinil treatment. Only one patient discontinued modafinil treatment because of a treatment-related adverse event (i.e. moderate headache); another patient discontinued due to insufficient efficacy.

CONCLUSIONS

Switching from methylphenidate to modafinil was well tolerated with or without a washout period or when the methylphenidate dose is gradually tapered during initiation of modafinil therapy. Daytime wakefulness was maintained in patients who have switched from methylphenidate to modafinil. These data suggest that patients with narcolepsy may be switched from methylphenidate to modafinil with few complications and inconveniences.