Rutgers study finds troubling side effects lead some patients to stop newer insomnia medication
NEW JERSEY — A new study involving Rutgers researchers found that about one in four people who reviewed a newer prescription insomnia medication online had stopped taking it or planned to stop, often citing frightening sleep experiences and next-day grogginess.
The study examined patient experiences with lemborexant, sold under the brand name Dayvigo, a medication approved in the United States in 2019 to treat insomnia. Researchers found that while some patients reported significant improvements in their sleep, others described troubling side effects, including sleep paralysis, vivid nightmares and lingering drowsiness.
Researchers from the Rutgers Brain Health Institute, Virginia Commonwealth University and the University of Sydney analyzed 260 online reviews of lemborexant posted between 2020 and 2023. Their findings were published in the journal Sleep Medicine.
Insomnia, which involves difficulty falling asleep or staying asleep, affects approximately 30% of adults, according to previous sleep research. Lemborexant belongs to a newer class of insomnia medications that block orexin, a chemical messenger that helps keep people awake, rather than broadly sedating the brain like many older sleeping medications.
Clinical trials have shown that lemborexant can help patients fall asleep faster and remain asleep longer compared with a placebo. However, the Rutgers-led analysis sought to better understand how patients experience the medication outside controlled clinical trials, particularly the side effects that may influence their decisions to continue treatment.
Of the 260 online reviewers, researchers identified 70 who had stopped taking the medication or planned to discontinue it. Those individuals were less likely to report improvements in their sleep, although complaints about poor or interrupted sleep were nearly as common among people who continued taking the drug.
Side effects were a more significant difference between the two groups. Sleep paralysis, a temporary condition in which someone is awake but unable to move or speak, appeared in 40% of reviews from people who stopped or planned to stop taking the medication, compared with 15% of reviews from others. Vivid dreams, nightmares and next-day grogginess were also more frequently reported among those considering discontinuation.
“What surprised us most was how unsettling some patients found certain side effects,” said Abanoub J. Armanious, a pharmacoepidemiologist and neuropsychiatry researcher with the Rutgers Brain Health Institute and lead author of the study. “For these individuals, stopping the medication was not simply about it failing to improve sleep.”
Patient experiences varied considerably, with the most common rating being 1 out of 10, followed by 10 out of 10. Approximately one-third of reviewers said the medication meaningfully improved their sleep, while half reported little or no benefit. About two-thirds mentioned at least one side effect.
“It feels like I am sleeping naturally like I did once upon a time,” one person wrote online about lemborexant, rating it 10 out of 10.
Another reviewer described a frightening episode of sleep paralysis and rated the medication a 1.
“Felt paralyzed to move. Wanted to scream and could not make a sound,” the reviewer noted. “Was able to touch my husband’s arm and waken him. He said he never saw such terror in my eyes.”
Other reviewers described unusually intense dreams and nightmares that influenced their decisions to stop treatment.
“The dreams [nightmares] are VERY vivid and that’s the reason I can no longer take this medication,” one reviewer wrote.
Researchers said a possible explanation for the nightmares and sleep paralysis involves rapid eye movement sleep, the stage of sleep associated with dreaming. During this stage, the brain normally prevents most muscles from moving. Because blocking orexin can increase dreaming sleep, researchers suggested that vivid dreams and temporary muscle paralysis may sometimes carry over into moments of wakefulness.
Not all patients considered the unusual dreams unpleasant. One reviewer who rated the medication a 9 out of 10 said they looked forward to the “wild crazy dreams.”
“One of the important messages from our study is that lemborexant was reported to work very well for some people,” said Morgan James, senior author of the study, adjunct assistant professor at the Rutgers Brain Health Institute and Horizon Fellow and senior lecturer at the University of Sydney’s Brain and Mind Centre and School of Psychology.
The researchers cautioned that the online reviews cannot establish how frequently side effects occur among all patients taking lemborexant. People who have particularly positive or negative experiences may be more likely to post reviews, making the comments unrepresentative of the broader patient population.
In the medication’s two main clinical trials, which monitored all enrolled participants, fewer than 2% of those taking lemborexant experienced sleep paralysis, while approximately 1% to 3% reported nightmares or abnormal dreams. By comparison, about one in five online reviewers mentioned sleep paralysis, and nearly one-third described vivid dreams or nightmares.
“A clinical trial can tell you how often side effects occur,” Armanious said. “It is less equipped to tell you how much that side effect matters to the person living it. A side effect can be rare and still be the reason someone discontinues treatment.”
Most people who posted reviews had taken the medication for less than a month, particularly those who stopped or planned to stop. Patients who reported longer-term use generally gave the medication higher ratings, although researchers said the study could not determine why those differences occurred.
The findings highlight the importance of discussing potential side effects and individual treatment needs with health care providers. Researchers emphasized that patients should be informed about possible reactions without becoming unnecessarily alarmed and should consult a clinician before stopping or changing any prescribed sleep medication.
“What really stands out is how different people’s experiences with this medication can be, which highlights the importance of setting expectations and finding the right treatment for the individual,” James said.
The research was funded in part by the National Institute on Drug Abuse, part of the National Institutes of Health, through grants DA045765 and DA063103, as well as a Horizon Fellowship from the University of Sydney. The researchers noted that the findings do not necessarily represent the official views of the National Institutes of Health.
The Rutgers Brain Health Institute is also investigating whether orexin-based sleep medications could potentially be used to treat sleep disturbances associated with psychiatric conditions, including addiction.
