Lemborexant, sold under the brand name Dayvigo, is an oral medication approved for the treatment of insomnia in adults, specifically addressing difficulties with sleep onset and/or sleep maintenance.[1] Developed by the pharmaceutical company Eisai, it represents a novel class of sleep aids known as dual orexin receptor antagonists (DORAs).[2] First approved by the U.S. Food and Drug Administration (FDA) on December 20, 2019, lemborexant is classified as a Schedule IV controlled substance due to its low potential for abuse and dependence.[3][1]Lemborexant exerts its therapeutic effects by competitively antagonizing the orexin receptors OX1R and OX2R in the central nervous system, thereby blocking the wake-promoting actions of endogenous orexins (also known as hypocretins) and promoting both non-REM and REM sleep stages.[1] This mechanism differs from traditional sleeping pills such as benzodiazepines (e.g., diazepam) and non-benzodiazepine Z-drugs (e.g., zolpidem, zopiclone), which act on GABA-A receptors to enhance central nervous inhibition, often causing abnormal sleep structure including REM suppression, next-day residual drowsiness, high risk of tolerance, dependence, and addiction, as well as rebound insomnia upon withdrawal.[1][4] In contrast, lemborexant promotes natural-like sleep onset by inhibiting the orexin system without direct GABA enhancement, preserving sleep architecture and improving NREM and REM quality, exhibiting very low abuse and addiction potential with no significant withdrawal or rebound effects even after 12 months of use, and minimal next-day residual effects, representing a safer profile for long-term use.[4][5][6] The drug is rapidly absorbed following oral administration, reaching peak plasma concentrations within 1 to 3 hours, with an elimination half-life of approximately 17 to 19 hours that supports sustained sleep without significant accumulation upon repeated dosing.[1] Available in 5 mg and 10 mg tablets, it is recommended to be taken once nightly immediately before bedtime, with at least 7 hours intended for sleep, and preferably on an empty stomach to optimize onset.[7][1]Clinical studies supporting its approval demonstrated significant improvements in sleep efficiency and reductions in sleep latency compared to placebo, with efficacy maintained over 6 to 12 months in long-term trials.[1] Common adverse effects include somnolence (affecting about 10% of users), headache, and fatigue, while more serious risks encompass complex sleep behaviors (such as sleepwalking), sleep paralysis, and potential worsening of depression or suicidal ideation.[1][7] Contraindicated in patients with narcolepsy, it requires caution in those with hepatic impairment, elderly individuals, or concurrent use of CYP3A inhibitors, as these can alter its pharmacokinetics.[1] As of 2025, research has shown promise for its use in Alzheimer's disease-related sleep disturbances, including preclinical studies demonstrating reduced tau pathology and improved nighttime behaviors in patients.[8][9]
Medical uses
Indications
Lemborexant is indicated for the treatment of insomnia in adult patients characterized by difficulties with sleep onset and/or sleepmaintenance.[10]The efficacy of lemborexant was demonstrated in two pivotal phase 3 clinical trials, SUNRISE 1 and SUNRISE 2. In SUNRISE 1, a randomized, double-blind study involving adults with insomnia disorder, lemborexant at doses of 5 mg and 10 mg significantly reduced sleep onset latency (sTSO) and wake after sleep onset (sWASO) compared to placebo, as measured by polysomnography over one month, while also improving sleep efficiency (SE).[11] Similarly, SUNRISE 2, a six-month randomized, double-blind trial, showed sustained improvements with lemborexant 5 mg and 10 mg versus placebo in sTSO, sWASO, and SE, with a higher percentage of responders for both sleep onset and maintenance outcomes.[12]Lemborexant is not indicated for use in pediatric patients, as safety and effectiveness have not been established in individuals under 18 years of age.[10] It is also not approved for other sleep disorders, such as sleep apnea, and patients with persistent insomnia should be reevaluated for potential comorbid conditions.[10] As of 2025, no new primary indications have been approved beyond adult insomnia, though off-label considerations remain limited to specific insomnia subtypes without additional supportive evidence.[10]
Dosage and administration
Lemborexant is available as oral tablets in 5 mg and 10 mg strengths.[10]The recommended starting dose is 5 mg taken no more than once per night, immediately before going to bed, with at least 7 hours remaining before the planned time of awakening; the dose may be increased to a maximum of 10 mg once nightly based on clinical response and tolerability.[10]Tablets should be swallowed whole and may be taken with or without food, although administration with or soon after a meal may delay the time to sleep onset.[10] Patients should avoid alcohol and other central nervous system depressants on the same night as lemborexant to minimize the risk of excessive sedation.[10]In elderly patients (≥65 years), the recommended dosing is the same as for adults, but caution is advised when using doses above 5 mg due to increased risk of somnolence.[10] For patients with moderate hepatic impairment, the maximum dose is 5 mg once nightly, while use is not recommended in those with severe hepatic impairment.[10]Dose adjustments are required with concomitant CYP3A inhibitors: strong and moderate inhibitors should be avoided, while weak inhibitors necessitate a maximum dose of 5 mg; strong and moderate CYP3A inducers should also be avoided.[10]
Adverse effects
Common side effects
The most common adverse reactions associated with lemborexant, occurring in at least 2% of patients and at a rate greater than placebo in clinical trials, include somnolence or fatigue, headache, and nightmare or abnormal dreams.[10] In pooled data from phase 3 studies (SUNRISE 1 and 2), somnolence or fatigue was reported in 6.9% of patients on 5 mg, 9.6% on 10 mg, and 1.3% on placebo, often manifesting as next-day drowsiness. This incidence of next-day drowsiness is lower compared to that observed with traditional GABAergic hypnotics such as benzodiazepines and non-benzodiazepine hypnotics (e.g., zolpidem), which often cause more pronounced residual effects and impairments.[10][13]Headache occurred in 5.9% of patients on 5 mg, 4.5% on 10 mg, and 3.4% on placebo.[10]Nightmare or abnormal dreams, which may be vivid or intense, were reported in 0.9% of patients on 5 mg, 2.2% on 10 mg, and 0.9% on placebo.[10] As a dual orexin receptor antagonist, lemborexant increases rapid eye movement (REM) sleep, during which dreaming occurs and dream content is more likely to be recalled, potentially contributing to these experiences.[14] There is no official or scientifically established spiritual meaning for these dreams. Anecdotal reports from users have sometimes interpreted them as subconscious messages, spiritual warnings, or signs of mental/emotional processing and healing, but such interpretations are personal, subjective, and lack medical or scientific support.These effects are generally mild to moderate and self-limiting, resolving without intervention in most cases. Unlike traditional sleeping pills such as benzodiazepines and zolpidem, lemborexant is not associated with rebound insomnia or significant withdrawal symptoms upon discontinuation, even after long-term use of up to 12 months.[10][13] Patients should be advised to avoid driving or operating machinery the day after taking lemborexant, particularly at the 10 mg dose, due to potential impairment from residual somnolence, and to monitor for risks like falls in older adults.[10]
Serious adverse effects
Lemborexant carries risks of complex sleep behaviors, such as sleepwalking, sleep-driving, and engaging in other activities while not fully awake, which can result in serious injury or death; patients should be instructed to discontinue the medication immediately if such events occur.[10] These behaviors have been reported in clinical trials, with two events noted in patients receiving the 10 mg dose.[10]Other serious effects include sleep paralysis and hypnagogic or hypnopompic hallucinations, occurring at incidences of 1.3% (5 mg) to 1.6% (10 mg) for sleep paralysis and 0.1% (5 mg) to 0.7% (10 mg) for hallucinations, compared to 0% for placebo.[10] These symptoms typically resolve upon discontinuation of the drug.[10]Worsening of depression and suicidal ideation occurred in 0.4% of patients on 5 mg and 0.3% on 10 mg, compared to 0.2% on placebo; close monitoring is recommended, especially in patients with a history of depression.[10]In patients with compromised respiratory function, such as those with chronic obstructive pulmonary disease (COPD) or obstructive sleep apnea (OSA), lemborexant may exacerbate respiratory depression, though short-term studies showed no significant impact on respiratory parameters in mild OSA.[10] Caution is advised, particularly with concomitant use of CNS depressants like alcohol, which can enhance these effects.[10]As a Schedule IV controlled substance under the Controlled Substances Act, lemborexant has a low potential for abuse and dependence compared to higher-scheduled substances, though misuse may occur in individuals with a history of substance abuse.[15][1]Overdose with lemborexant primarily manifests as excessive somnolence, with doses up to 75 mg (seven and a half times the maximum recommended) causing dose-dependent sedation but no serious outcomes in limited reports; there is no specific antidote, and treatment involves supportive care and monitoring.[10]
Contraindications and drug interactions
Contraindications
Lemborexant is contraindicated in patients with narcolepsy, as orexin receptor antagonists may exacerbate narcolepsy symptoms or induce cataplexy-like episodes.[16]Lemborexant should be avoided in individuals with known hypersensitivity to lemborexant or any of its excipients, as this may lead to serious allergic reactions including anaphylaxis or angioedema.[17]
Drug interactions
Lemborexant is primarily metabolized by the cytochrome P450 3A (CYP3A) enzyme in the liver, leading to potential pharmacokinetic interactions with modulators of this pathway.[10]Concomitant use of strong or moderate CYP3A inhibitors, such as ketoconazole, itraconazole, and fluconazole, is not recommended due to significantly increased lemborexant exposure (e.g., up to 4-fold increase in AUC with moderate inhibitors like fluconazole), raising the risk of adverse effects; if unavoidable, the dose should be limited to 5 mg. For weak CYP3A inhibitors like verapamil, a dose reduction to 5 mg should be considered.[10][18][1]In contrast, strong CYP3A inducers such as rifampin substantially decrease lemborexant exposure (e.g., >90% reduction in Cmax and AUC), potentially reducing its efficacy for insomnia treatment; coadministration should be avoided. Moderate inducers like carbamazepine also warrant avoidance.[10][18][1]Alcohol interacts with lemborexant through additive central nervous system (CNS) depression, resulting in greater impairment of postural stability and cognitive functions, such as memory, compared to alcohol alone; patients should avoid alcohol during treatment, including if intoxicated from recent consumption.[10]Other CNS depressants, including benzodiazepines like lorazepam, enhance the sedative effects of lemborexant, increasing risks of excessive drowsiness, dizziness, and impaired coordination; coadministration is not recommended, and dosage adjustments may be necessary if used together.[10][1]Lemborexant shows no significant pharmacokinetic interactions with common antidepressants (e.g., SSRIs) or antihypertensives, though pharmacodynamic effects with certain sedating antidepressants should be monitored.[18][1]