Solriamfetol Shows Promise in Enhancing Alertness and Safety for Early Morning Shift Workers Suffering from Shift Work Disorder

A groundbreaking clinical trial led by researchers at Mass General Brigham has demonstrated that the wake-promoting medication solriamfetol, marketed under the brand name Sunosi, significantly improves alertness and functional performance in individuals working early morning shifts. The study, recently published in NEJM Evidence, marks the first time a clinical trial has specifically targeted the "early bird" demographic of shift workers—those who begin their duties between 3:00 a.m. and 7:00 a.m.—a group that represents the most common form of non-traditional work scheduling but remains largely underserved by medical research. While much of the existing literature on Shift Work Disorder (SWD) focuses on overnight or "graveyard" shifts, this new data suggests that the biological toll of starting work before dawn is equally severe and requires specialized therapeutic intervention.

Shift Work Disorder is a chronic circadian rhythm sleep-wake disorder characterized by excessive sleepiness during work hours and insomnia when the individual attempts to sleep. For those starting work in the early hours of the morning, the condition arises because they are forced to terminate their sleep during the period when the body’s internal biological clock is most strongly promoting rest. This misalignment leads to significant deficits in concentration, increased safety risks, and a diminished quality of life. The findings from Mass General Brigham provide a potential roadmap for mitigating these risks through pharmacological support that aligns more effectively with the modern workforce’s demands.

The Hidden Prevalence of Early Morning Shift Work

The modern global economy operates on a 24-hour cycle, necessitating that roughly 20% to 25% of the workforce operates outside the traditional 9-to-5 window. Within this group, early morning workers constitute a massive yet often overlooked segment. These individuals include healthcare professionals, transportation workers, bakers, stock traders, and manufacturing staff. Unlike overnight workers, many early morning workers do not identify as "shift workers," often viewing their schedules as merely an extension of the normal day. However, the physiological reality is far more taxing.

Dr. Charles A. Czeisler, chief and senior physician of the Division of Sleep and Circadian Medicine at Mass General Brigham and senior author of the study, noted that this study addresses a major gap in occupational health. He emphasized that early morning workers are often forced to wake up during their biological "circadian trough"—the time of day when core body temperature is lowest and the drive for sleep is highest. By focusing on this specific population, the researchers have highlighted a public health issue that affects millions but has lacked a validated clinical treatment protocol until now.

Understanding the Biological Conflict

The human circadian system is governed by the suprachiasmatic nucleus (SCN) in the brain, which regulates the release of hormones like melatonin and cortisol based on light exposure. For a person starting a shift at 4:00 a.m., the alarm clock usually rings around 2:30 a.m. or 3:00 a.m. At this hour, the brain is still in a phase of deep sleep and high melatonin production. Waking up at this time creates a state of "sleep inertia" that can persist for hours, significantly impairing cognitive function.

First author Kirsi-Marja Zitting, PhD, an investigator with the Division of Sleep and Circadian Medicine, explained that these workers face a "double burden." They must fight intense physiological pressure to sleep while performing high-stakes tasks, and then, when they return home in the early afternoon, they often struggle to find a quiet, dark environment conducive to the restorative sleep they missed. This cycle leads to chronic sleep deprivation, which is linked to metabolic disorders, cardiovascular disease, and mental health challenges.

Methodology of the Solriamfetol Clinical Trial

The clinical trial was designed as a randomized, double-blind, placebo-controlled study to evaluate the efficacy of solriamfetol in a real-world context. The researchers recruited 78 participants who met the clinical criteria for Shift Work Disorder and were currently employed in early morning shifts. Over a four-week period, half of the participants were administered solriamfetol on their workdays, while the other half received a placebo.

To measure the drug’s effectiveness, the team utilized the Maintenance of Wakefulness Test (MWT), a standardized assessment that measures an individual’s ability to remain awake in a dark, quiet environment. This test is considered the gold standard for evaluating wake-promoting agents because it simulates the "low-stimulation" environments where fatigue-related accidents are most likely to occur, such as long-haul driving or monitoring industrial equipment.

In addition to the objective MWT data, the researchers collected subjective reports from the participants and clinical assessments from physicians. These metrics focused on "Global Impression of Change," which tracks how much the patient’s overall condition has improved or worsened since the start of the treatment.

Key Findings and Statistical Outcomes

The results of the trial were conclusive. After four weeks, the group receiving solriamfetol demonstrated a marked increase in their ability to stay awake during simulated work hours compared to the placebo group. Specifically:

1. Increased Wakefulness: Participants on solriamfetol could remain awake significantly longer on the MWT, showing that the drug effectively countered the biological drive to sleep during the early morning hours.
2. Improved Occupational Functioning: Both clinicians and patients reported substantial improvements in work performance. Participants noted that they felt more "present" and less prone to the "brain fog" that typically plagued their early shifts.
3. Safety and Tolerability: The drug was generally well-tolerated. Crucially, unlike some older stimulants, solriamfetol did not appear to significantly interfere with the participants’ ability to fall asleep later in the day once their shift ended. This is a vital distinction, as many shift workers avoid stimulants because they fear being unable to rest during their designated sleep windows.

Dr. Czeisler remarked that the improvements were "clinically meaningful," suggesting that the drug does not merely mask sleepiness but actually restores a level of alertness comparable to that of a person working a standard daytime schedule.

The Pharmacological Advantage of Solriamfetol

Solriamfetol is a dual dopamine and norepinephrine reuptake inhibitor (DNRI). It was originally FDA-approved in 2019 for the treatment of excessive daytime sleepiness associated with narcolepsy and obstructive sleep apnea (OSA). Its mechanism of action differs from traditional stimulants like amphetamines, which can have a higher potential for abuse and cardiovascular strain.

In the context of shift work, solriamfetol offers a distinct advantage over modafinil, another commonly prescribed wake-promoting agent. While modafinil has been the primary treatment for overnight workers, some patients report that its effects last too long, making it difficult to transition back to sleep. Solriamfetol’s pharmacokinetic profile allows for a robust period of alertness that aligns well with an eight-to-ten-hour shift, tapering off in time for the worker to rest.

Implications for Public Safety and the Economy

The implications of this study extend far beyond the individual worker. Fatigue is a leading cause of workplace accidents and transportation disasters. According to the National Highway Traffic Safety Administration (NHTSA), drowsy driving is responsible for thousands of fatalities and tens of thousands of injuries annually in the United States alone. For early morning workers, the commute to work is often the most dangerous part of the day, as they are driving during the peak of their circadian sleepiness.

Furthermore, the economic cost of sleep disorders is staggering. Reduced productivity, absenteeism, and healthcare expenses related to fatigue-related illnesses cost the U.S. economy an estimated $411 billion per year. By providing an effective treatment for SWD in early morning workers, solriamfetol could potentially reduce these costs while improving the safety of essential services like public transit and emergency medical care.

Expert Reactions and Future Directions

The sleep medicine community has welcomed the findings as a necessary step toward personalized chronomedicine. While the results are promising, the researchers at Mass General Brigham have been careful to note the study’s limitations. The trial lasted only four weeks and involved a relatively small, healthy adult population. Long-term studies are required to determine if the efficacy of the drug remains stable over months or years and to monitor for any delayed side effects.

"Shift workers are essential to how our society functions," Dr. Czeisler stated. "They are the ones who ensure the power is on, the bread is baked, and the hospitals are staffed before the rest of the world wakes up. Yet, they often pay a hidden biological cost. This study shows we can do better for them by providing tools that help them manage the physiological strain of their essential roles."

The research team is currently moving forward with a follow-up clinical trial that will evaluate the effects of solriamfetol on overnight shift workers. This broader research initiative aims to secure comprehensive regulatory approval for solriamfetol as a primary treatment for all forms of Shift Work Disorder, potentially changing the standard of care for millions of non-traditional workers worldwide.

Conclusion

The Mass General Brigham study represents a pivotal moment in the treatment of circadian rhythm disorders. By validating the use of solriamfetol for early morning shift workers, the research provides a scientifically backed solution to a problem that has long been dismissed as "part of the job." As society continues to rely on around-the-clock labor, the integration of such pharmacological advancements will be crucial in balancing the demands of the modern economy with the fundamental biological needs of the human body. For the millions of workers who start their day in the dark, these findings offer the prospect of a safer, more alert, and more productive future.