Lemborexant

Introduction Overview

Generic Name

lemborexant

Brand Name

Dayvigo

Dosage Form

oral tablet

Drug Class

Miscellaneous anxiolytics, sedatives and hypnotics (Dual Orexin Receptor Antagonist - DORA)

Pharmacokinetics

Absorption:
Lemborexant, the active ingredient in Dayvigo, is rapidly absorbed following oral administration. Peak plasma concentrations are typically reached within 1 to 3 hours after dosing under fasting conditions. However, the rate of absorption may be delayed if the drug is taken with or shortly after a meal, particularly high-fat meals, which can prolong the time to peak concentration without substantially impacting overall bioavailability. This delayed absorption should be considered clinically, as taking Dayvigo on an empty stomach is recommended to optimize therapeutic onset for insomnia treatment.

Distribution:
Following absorption, lemborexant is extensively distributed throughout the body with a large volume of distribution, indicating significant tissue penetration, especially in the central nervous system where it exerts its pharmacological effects. Lemborexant is highly bound to plasma proteins, primarily albumin (greater than 90%), which may influence both its free active concentration and potential drug interactions. Its lipophilic nature facilitates crossing the blood-brain barrier, enabling effective antagonism of orexin receptors localized in the hypothalamus.

Metabolism:
Lemborexant undergoes extensive hepatic metabolism predominantly via the cytochrome P450 enzyme CYP3A4. The major metabolic pathways include oxidative biotransformation leading to several inactive metabolites. The involvement of CYP3A4 means that lemborexant's plasma levels can be significantly affected by concomitant use of strong CYP3A4 inhibitors or inducers, necessitating dose adjustments or contraindications in certain clinical scenarios. There is no evidence that lemborexant forms active metabolites contributing to its hypnotic effect.

Elimination:
The elimination of lemborexant primarily occurs through fecal excretion of metabolites, with a minor proportion eliminated renally. The mean terminal elimination half-life ranges between approximately 17 to 19 hours, supporting once-daily dosing at bedtime. However, prolonged half-life may contribute to residual next-day sleepiness in some patients. Hepatic impairment, especially moderate impairment, reduces clearance, warranting dosage adjustments. In contrast, severe hepatic impairment is a contraindication due to significantly altered pharmacokinetics and increased risk of adverse effects.

Dosage Forms

Available Dosage Forms:
Dayvigo is available exclusively as an oral tablet, film-coated for ease of administration. The tablets come in two strengths to accommodate varying therapeutic needs:
- 5 mg film-coated oral tablet
- 10 mg film-coated oral tablet

Dosages for Adults and Adolescents:
Dayvigo is indicated for adults with insomnia characterized by difficulties in sleep onset and/or maintenance. The recommended initial dose is 5 mg orally once per night immediately before bedtime, with at least 7 hours dedicated to sleep before planned awakening. Based on efficacy and tolerability, the dose may be increased to a maximum of 10 mg once nightly. Use in adolescents under 18 years is not established and is not recommended due to lack of safety and efficacy data.

Specific Patient Populations:
- Hepatic Impairment: For patients with moderate hepatic impairment (Child-Pugh class B), the maximum recommended dose is 5 mg once nightly, with careful monitoring. Dayvigo is not recommended for patients with severe hepatic impairment (Child-Pugh class C).
- Renal Impairment: No dose adjustment is necessary for mild to moderate renal impairment; data is limited in severe renal impairment.
- Geriatric Patients: No specific dosage adjustment is mandated, but increased sensitivity to the sedative effects should be considered.
- Pediatric Population: Safety and efficacy in children and adolescents under 18 years remain unestablished; thus, Dayvigo is not recommended.

Clinical guidelines emphasize administration immediately before bedtime when the patient can commit to an uninterrupted sleep period of 7 or more hours, optimizing therapeutic benefits and minimizing residual daytime sedation.

Mechanism Of Action

Dayvigo (lemborexant) exerts its pharmacological effect through selective antagonism of orexin receptors, specifically OX1R and OX2R, which are G-protein coupled receptors located principally in the lateral hypothalamus. Orexin neuropeptides (orexin A and orexin B) regulate wakefulness and arousal by binding to these receptors, promoting sustained alertness and preventing transitions into sleep.

By blocking the binding of orexin A and B to their receptors, lemborexant suppresses the wake-promoting signaling downstream in the central nervous system. This inhibition facilitates the natural onset of sleep and helps maintain sleep continuity by diminishing the brain’s alert state intensity, differing mechanistically from traditional sedative-hypnotics that primarily potentiate gamma-aminobutyric acid (GABA) transmission.

Cellularly, orexin receptor antagonism reduces neuronal excitability in arousal-related pathways, including monoaminergic and glutamatergic circuits, thereby shifting the sleep-wake balance in favor of sleep. This targeted receptor-specific mechanism reduces common side effects associated with benzodiazepines and non-benzodiazepine hypnotics, such as cognitive impairment and dependence potential.

Clinical trials have demonstrated that dual orexin receptor antagonists like lemborexant bring about improved sleep onset latency and increased total sleep time without significant alterations to sleep architecture. This pharmacodynamic profile relates to its differentiated mode of action, offering an effective therapeutic option for insomnia with a relatively favorable safety and tolerability profile compared to other hypnotics.

Pharmacological Actions

Selective antagonism of orexin type 1 and type 2 receptors inhibiting orexin-mediated wakefulness.
Promotion of sleep initiation and maintenance through suppression of central nervous system arousal pathways.
Reduction of sleep latency by facilitating transition from wakefulness to sleep.
Enhancement of sleep continuity, decreasing nocturnal awakenings and improving overall sleep quality.
Lack of significant modulation of GABAergic systems, resulting in reduced cognitive impairment and dependence risk.
Minimal impact on respiratory function, making it safer in patients with mild respiratory conditions compared to other sedatives.
Absence of active metabolites contributing to primary pharmacological effects, supporting predictable dose-response relationships.
Rapid onset of action, typically within 20 minutes under fasting conditions.
Prolonged half-life supporting once-daily dosing and sustained efficacy throughout the night.
Demonstrated anxiolytic-sedative profile unique to orexin receptor antagonism.

Therapeutic Or Clinical Uses

Treatment of adult patients with insomnia characterized by difficulties with sleep onset and/or sleep maintenance.
Improvement of sleep latency to reduce time taken to fall asleep.
Extension of total sleep time to enhance sleep continuity and quality.
Management of chronic insomnia with demonstrated efficacy over extended treatment periods up to six months.
Alternative treatment option for patients who are intolerant or unresponsive to traditional benzodiazepine or non-benzodiazepine hypnotics.
Use in patients where minimizing next-day residual sedation and cognitive dysfunction is clinically important.
Therapeutic utility in patients at risk of dependence with other hypnotics due to lower abuse potential.
Potential treatment adjunct in patients with concomitant anxiety disorders requiring sedative support.
Considered for patients with sleep difficulties inadequately managed by non-pharmacologic interventions.
Limited evidence for use in populations with mild to moderate liver impairment with appropriate dose adjustments.

Side Or Adverse Effects

Somnolence and excessive daytime sleepiness, the most commonly reported adverse effect.
Headache, often mild to moderate in intensity.
Abnormal or vivid dreams including nightmares.
Sleep paralysis episodes occurring at sleep onset or upon awakening, characterized by temporary inability to move or speak.
Complex sleep behaviors such as sleepwalking, sleep-driving, and performing activities while not fully awake, sometimes with amnesia for the events.
Worsening of depression or emergence of suicidal ideation during treatment necessitating immediate medical evaluation.
Dizziness and impaired coordination, increasing fall risk especially in elderly patients.
Potential for rebound insomnia or withdrawal symptoms if abruptly discontinued after prolonged use.
Rare but serious events of impaired driving or activity requiring patient education regarding next-day impairment.
Gastrointestinal disturbances including nausea or dry mouth reported infrequently.
Respiratory depression risk is low but caution advised in patients with underlying respiratory conditions.
Allergic reactions such as rash or hypersensitivity are rare but possible.
Dependence and abuse potential, albeit lower than benzodiazepines, especially in patients with history of substance abuse.
Dayvigo may cause decreased alertness and impaired cognition the morning after dosing when patient fails to allocate sufficient sleep duration.

Precautions

Advise that Dayvigo should only be taken when the patient can stay in bed for a full night (at least 7 hours) before being active again.
Avoid activities requiring complete mental alertness, such as driving or operating machinery, if the patient has not had adequate sleep after dosing.
Use with caution in patients with a history of depression, mental illness, or suicidal ideation due to potential exacerbation.
Assess patients for history of substance abuse or addiction before prescribing due to the potential for dependence.
Caution in patients with moderate hepatic impairment; dose adjustment to 5 mg is recommended, and avoid use in severe hepatic impairment.
Monitor patients with respiratory diseases including sleep apnea; sedative effects of Dayvigo may exacerbate breathing difficulties.
Avoid concomitant use with other CNS depressants or medications that cause somnolence unless advised by healthcare provider.
Educate patients regarding the risk of complex sleep behaviors and instruct to report such events immediately.
Do not use in patients diagnosed with narcolepsy due to increased risk of adverse outcomes.
Consider risk-benefit in elderly, as increased sensitivity to sedatives and falls risk may exist.
Patients should report any worsening mood symptoms, including depression or suicidal thoughts promptly.
Alcohol consumption should be strictly avoided during treatment as it potentiates sedative and cognitive impairment effects.
Inform patients about the schedule IV controlled substance status and the importance of secure storage to prevent misuse.
Avoid abrupt discontinuation to prevent potential withdrawal or rebound insomnia symptoms.

Warnings

Dayvigo is a Schedule IV controlled substance with potential for abuse and dependence.
Decreased awareness and alertness the morning after administration can impair driving and operating machinery.
Risk of complex sleep behaviors including sleepwalking, sleep-driving, and other activities without full awareness.
Risk of sleep paralysis episodes that can cause temporary inability to move or talk during the transition between sleep and wakefulness.
Worsening depression, suicidal ideation, or behavioral changes may occur; close monitoring is essential.
Not recommended for use in patients with narcolepsy due to potential exacerbation of symptoms.
Use caution in patients with moderate to severe hepatic impairment; contraindicated in severe hepatic impairment.
Concurrent use with other sedatives or CNS depressants may potentiate sedative effects, increasing risk of respiratory depression and overdose.
Potential next-day impairment warrants that patients ensure a full 7 hours of sleep after taking Dayvigo.
Avoid use in pregnancy and breastfeeding unless clearly needed; insufficient data on safety.
Misuse, diversion, or recreational use poses serious legal and health risks.
Risk of somnambulism and other parasomnias requires patient education and prompt reporting.
Potential drug interactions may alter efficacy or safety profile.
Careful patient selection and adherence to dosing instructions must be emphasized to minimize adverse outcomes.

Contraindication

Known hypersensitivity to lemborexant or any component of Dayvigo formulation.
Patients with narcolepsy or a history of narcolepsy; Dayvigo is contraindicated due to risk of severe adverse effects.
Severe hepatic impairment (Child-Pugh class C) due to significantly altered pharmacokinetics and increased toxicity risk.
Concomitant use with strong CYP3A4 inhibitors when dose modifications or alternative therapies are not feasible.
Patients who have experienced complex sleep behaviors with previous hypnotics should avoid Dayvigo.
Use in pediatric patients under 18 years has not been established and is thus contraindicated.
Avoid use in patients with active or severe respiratory impairment unless under specialist supervision.
Known history of severe allergic reactions to orexin receptor antagonists or formulation excipients.
Primary hypersensitivity to ingredients in the film coating such as hypromellose, polyethylene glycol, talc, titanium dioxide, or ferric oxides.
Co-administration with other sedative-hypnotics without physician guidance.

Drug Interactions

Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole) can significantly increase lemborexant plasma concentrations and risk of adverse effects.
CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin) may decrease lemborexant levels, reducing efficacy.
Co-administration with other CNS depressants including benzodiazepines, opioids, alcohol, and other sedative agents may enhance sedation and respiratory depression.
Concomitant use with moderate CYP3A4 inhibitors requires monitoring and possible dose adjustments.
Potential pharmacodynamic interaction with drugs affecting neuropsychiatric status, requiring close monitoring.
Antidepressants like SSRIs or SNRIs could augment CNS effects necessitating careful clinical evaluation.
No significant interaction observed with common medications like antihypertensives and most non-CYP3A4 metabolized drugs.
Drugs altering gastric pH or gastrointestinal motility minimally affect lemborexant absorption.
Avoid combining with other orexin receptor antagonists or experimental agents targeting sleep-wake regulation.
Dayvigo does not have significant inhibitory or inductive effects on CYP enzymes affecting other drugs.
Herbal supplements such as St. John's Wort (a CYP3A4 inducer) can reduce Dayvigo efficacy.
Veterinary or other off-label interactions unknown and should be approached with caution.
Patients should maintain an updated medication list and consult healthcare providers before starting new drugs.
Interactions with other sedative medications may lead to amplified cognitive and motor impairment.

Preparations Of The Drug

Film-coated tablets formulated for oral administration to provide controlled release and stability.
5 mg tablet contains active lemborexant and inactive ingredients including hydroxypropyl cellulose, lactose monohydrate, low-substituted hydroxypropyl cellulose, magnesium stearate, and coating agents (hypromellose 2910, polyethylene glycol 8000, talc, titanium dioxide, ferric oxide yellow).
10 mg tablet shares the same composition except the film coating contains both ferric oxide yellow and ferric oxide red for differentiation.
Packaged in blister packs or bottles with child-resistant closures to prevent accidental ingestion.
Distributed by Eisai Inc., stored at controlled room temperature (68°F to 77°F or 20°C to 25°C), protected from moisture and light.
Available only by prescription as a controlled substance due to potential for abuse and dependence.
Prescribed with dosage titration guidelines and patient counseling on safe use, storage, and disposal.
No liquid or injectable formulations currently available; oral tablets are the sole marketed preparation.
Instructions emphasize administration immediately before bedtime with adequate sleep duration to optimize safety and efficacy.
Patient information leaflets provide comprehensive details on dosing, side effects, warnings, and precautions.