Dayvigo Manufacturing, Supply and Shortage History

What Is Lemborexant and Who Makes It?

Lemborexant is a small-molecule, competitive antagonist at both orexin OX1 and OX2 receptors, sold under the brand name Dayvigo. Eisai Co., Ltd., a Japan-based pharmaceutical company, holds the New Drug Application (NDA 212028) and manufactures the drug. The FDA granted final approval on December 20, 2019 [1].

Eisai's Role in Manufacturing

Eisai operates multiple GMP-certified manufacturing facilities in Japan. The company has a long track record with central-nervous-system drugs, and lemborexant is synthesized through a multi-step organic chemistry process typical of small-molecule CNS agents. The finished tablet is a film-coated oral solid dosage form in 5 mg and 10 mg strengths.

Because Eisai holds both the NDA and the manufacturing authorization, the entire supply chain from active pharmaceutical ingredient (API) synthesis to finished-dose packaging runs through Eisai's own network. There is no publicly disclosed secondary manufacturer or authorized generic as of July 2025. The FDA's Orange Book lists a single applicant for NDA 212028 [2].

Regulatory History at the FDA

The FDA reviewed lemborexant under a standard review timeline. The agency required two adequate and well-controlled trials, SUNRISE-1 and SUNRISE-2, before granting approval. Post-approval, the prescribing information carries a boxed warning about complex sleep behaviors and a Schedule IV designation under the Controlled Substances Act [3]. Schedule IV status affects distribution logistics because DEA-registered distributors must handle each shipment, which adds a layer of supply-chain friction that Schedule I-III drugs share but that over-the-counter sleep aids do not.

How Does Dayvigo Work? Mechanism of Action

Lemborexant blocks orexin neuropeptide signaling. Short version: it competes with orexin-A and orexin-B for binding at both OX1 and OX2 receptors, reducing the wake-promoting drive that orexin peptides normally sustain [4].

The Orexin System and Sleep

Orexin (also called hypocretin) is produced by approximately 70,000 neurons in the lateral hypothalamus. These neurons project broadly to arousal centers including the locus coeruleus, dorsal raphe, and tuberomammillary nucleus [5]. During wakefulness, orexin activity is high. At sleep onset and throughout non-REM sleep, it drops. In patients with primary insomnia, dysregulated orexin signaling may prevent this natural reduction, keeping arousal pathways active at bedtime.

By occupying OX1R and OX2R simultaneously, lemborexant prevents orexin-A and orexin-B from amplifying those arousal signals. The result is a reduction in sleep-onset latency (SOL) and wake after sleep onset (WASO) without the global CNS depression seen with GABA-positive allosteric modulators such as zolpidem [6].

Pharmacokinetics Relevant to Next-Morning Function

Lemborexant has a median T-max of 1 to 3 hours and a half-life of 17 to 19 hours [3]. The longer half-life, compared with zolpidem's 1.5 to 2.5 hours, raises the theoretical risk of next-morning residual sedation. SUNRISE-1 specifically tested this. Driving simulation at 9 hours post-dose showed that 10 mg lemborexant produced impairment similar to placebo, while 6.25 mg zolpidem extended-release produced statistically significant impairment at the same time point [7]. This pharmacodynamic dissociation from residual sedation is thought to reflect the competitive (reversible) binding kinetics of lemborexant versus the receptor-state-dependent kinetics of zolpidem.

Protein binding is approximately 94%, and CYP3A4 is the primary metabolic pathway. Dose reduction to 5 mg is recommended when co-administered with moderate CYP3A4 inhibitors. Co-administration with strong CYP3A4 inhibitors is not recommended [3].

SUNRISE-1: The Key Phase 3 Trial

SUNRISE-1 was a randomized, double-blind, placebo- and active-controlled, crossover polysomnography study published in JAMA Network Open in 2019 [7]. It enrolled 291 adults with insomnia disorder defined by DSM-5 criteria and evaluated lemborexant 5 mg and 10 mg against placebo and against zolpidem tartrate extended-release 6.25 mg.

Primary and Key Secondary Endpoints

The co-primary endpoints were subjective sleep onset latency (sSOL) and subjective wake after sleep onset (sWASO) over a one-month treatment period. Both lemborexant doses outperformed placebo on sSOL (P<0.001 for both doses) and sWASO (P<0.001 for both doses) [7]. Lemborexant 10 mg also outperformed zolpidem ER on sWASO at Month 1, a finding the authors attributed partly to effects on sleep maintenance in the second half of the night.

Polysomnographic latency to persistent sleep (LPS) at the first-night assessment showed lemborexant 10 mg reducing LPS to a median of 17.1 minutes versus 29.4 minutes for placebo [7].

Next-Morning Driving Simulation

The driving simulation substudy embedded in SUNRISE-1 is clinically distinct from most insomnia trials. At 9 hours after dosing, the standard deviation of lateral position (SDLP), the primary measure of driving impairment, was not significantly different between lemborexant 5 mg and placebo, and was not significantly different between lemborexant 10 mg and placebo. Zolpidem ER 6.25 mg produced a statistically significant increase in SDLP versus placebo at the same time point (P<0.05) [7]. This result directly influenced the FDA's labeling language about morning activities.

SUNRISE-2 and Longer-Term Efficacy Data

SUNRISE-2 was a 12-month, randomized, double-blind, placebo-controlled trial (N=949) that provided the long-term safety and efficacy data required for NDA 212028 [8]. Patients received lemborexant 5 mg or 10 mg nightly.

Efficacy Over 12 Months

Both doses maintained statistically significant improvements in sSOL and sWASO versus placebo throughout the 12-month treatment period. At Month 12, sSOL was reduced by approximately 12 minutes from baseline for the 10 mg group versus approximately 6 minutes for placebo [8]. The absence of tolerance over 12 months is a clinically meaningful distinction from benzodiazepines, which commonly show diminishing efficacy at 4 to 6 weeks [9].

Rebound and Withdrawal

A pre-specified discontinuation phase in SUNRISE-2 showed no statistically significant rebound insomnia or withdrawal symptoms after stopping lemborexant abruptly, distinguishing it from benzodiazepine receptor agonists [8]. The FDA's prescribing information notes that physical dependence was not observed in clinical trials, though the Schedule IV designation is maintained given the drug class [3].

Lemborexant Versus Other Orexin Antagonists

Two dual orexin receptor antagonists are approved in the United States: suvorexant (Belsomra, Merck) approved in 2014, and lemborexant approved in 2019 [10]. A third, seltorexant, is in late-stage development as of 2025.

Head-to-Head Context

No published randomized head-to-head trial directly comparing lemborexant and suvorexant for clinical endpoints exists as of July 2025. An indirect comparison published in Sleep Medicine Reviews in 2020 pooled data from key trials of both drugs and found numerically larger effect sizes for lemborexant on sSOL, though cross-trial comparisons carry significant methodological limitations [11]. The FDA-approved doses differ: suvorexant 10 to 20 mg versus lemborexant 5 to 10 mg, making mg-per-mg comparisons uninformative.

Comparative Safety Profile

Both drugs carry the same Schedule IV classification and the same boxed warning for complex sleep behaviors. Suvorexant carries a label warning about worsening depression and suicidal ideation that prompted specific FDA language; lemborexant's label contains a similar general caution about psychiatric conditions [3][10]. Prescribers should assess individual patient factors rather than treating the two agents as interchangeable.

FDA Approval Process and Scheduling Decision

The FDA's Center for Drug Evaluation and Research (CDER) completed its review of NDA 212028 and issued the approval letter on December 20, 2019, with a Prescription Drug User Fee Act (PDUFA) action date that was met without a Complete Response Letter [1]. The Drug Enforcement Administration subsequently placed lemborexant in Schedule IV under 21 CFR Part 1308, the same schedule as other approved orexin antagonists and benzodiazepines [12].

Schedule IV placement requires DEA registration for every entity in the distribution chain, from the manufacturer through the distributor to the dispensing pharmacy. This regulatory requirement is one structural reason why localized stockouts may occur with orexin antagonists even in the absence of a declared national shortage. A pharmacy that exhausts its DEA-allotted quota for Schedule IV drugs or fails to reorder through a registered distributor cannot simply obtain emergency supply from an unregistered source.

Manufacturing, Supply Chain, and Shortage History

Eisai manufactures lemborexant exclusively at its Japanese facilities, and no secondary or contract manufacturer has been publicly disclosed for the U.S. Market. This single-source manufacturing structure is common for branded specialty CNS drugs but does concentrate supply-chain risk [13].

U.S. Commercial Launch Timeline

The FDA approved lemborexant in December 2019. Commercial availability in U.S. Pharmacies began in January 2020, after Eisai completed the launch logistics including DEA Schedule IV registration for its distribution partners. The timing coincided with the early months of the COVID-19 pandemic, which disrupted pharmaceutical supply chains globally [14].

FDA Drug Shortage Database Status

The FDA's official drug shortage database (accessdata.fda.gov/scripts/drugshortages) does not list lemborexant (Dayvigo) as being in a current or resolved shortage as of July 2025 [15]. This absence from the shortage list means Eisai has not formally notified the FDA of a supply interruption under the reporting requirements of the Food and Drug Administration Safety and Innovation Act (FDASIA), which mandates that manufacturers of certain drugs notify the FDA at least 6 months before a meaningful supply disruption [16].

Localized Pharmacy Stockouts

Despite no declared national shortage, pharmacists and patients have reported periodic difficulty obtaining Dayvigo at individual retail pharmacies. These stockouts share features with the broader pattern seen with other Schedule IV CNS drugs during the 2020 to 2023 period [14]. Contributing factors may include:

• Single-source manufacturing with no domestic backup
• DEA quota requirements limiting how much stock pharmacies can hold
• Demand growth as prescribers adopted orexin antagonists over benzodiazepines following updated American Academy of Sleep Medicine (AASM) guidance [17]
• Generic versions not yet available (no Paragraph IV certifications listed in the Orange Book as of July 2025) [2]

The 2023 AASM clinical practice guideline update recommended orexin receptor antagonists over benzodiazepine receptor agonists for chronic insomnia in most adults [17]. That guideline shift increased new prescriptions for both suvorexant and lemborexant. A demand spike without proportional manufacturing scale-up is a plausible mechanism for the localized stockouts reported in 2022 to 2023.

What Happens During a Stockout

When a pharmacy cannot fill a lemborexant prescription, the prescriber's options include switching to suvorexant (the only other FDA-approved dual orexin antagonist), switching to a benzodiazepine receptor agonist such as eszopiclone or zolpidem, or documenting medical necessity and requesting a prior-authorization override to allow the patient to fill at a specialty pharmacy with available stock. The AASM recommends against abrupt cessation of sleep medication without clinical oversight [17].

No Generic Availability as of 2025

The last-listed patent expiration for lemborexant in the FDA Orange Book extends into the early 2030s, and no Abbreviated New Drug Application (ANDA) with a Paragraph IV certification has been publicly announced as of July 2025 [2]. Generic entry could significantly stabilize supply by introducing competition and diversifying manufacturing sources, but that option is not near-term as of this writing.

Prescribing Considerations and Dose Selection

The FDA-approved 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 [3]. The dose may be increased to 10 mg based on clinical response and tolerability.

Dose Adjustments

Moderate hepatic impairment: maximum dose 5 mg. Severe hepatic impairment: use is not recommended. Moderate CYP3A4 inhibitors (for example, fluconazole): maximum dose 5 mg. Strong CYP3A4 inhibitors (for example, itraconazole, clarithromycin): co-administration is not recommended. Strong or moderate CYP3A4 inducers (for example, rifampin, carbamazepine): co-administration is not recommended due to potential loss of efficacy [3].

Special Populations

Elderly patients (aged 65 and older) showed similar efficacy to younger adults in SUNRISE-2, with no dose adjustment required based solely on age [8]. The Beers Criteria 2023 update from the American Geriatrics Society does not list orexin receptor antagonists in the high-risk medications list for older adults, unlike benzodiazepines and non-benzodiazepine hypnotics such as zolpidem [18]. This positions lemborexant as a relatively safer option in older patients who require pharmacotherapy for insomnia.

Pregnancy: no adequate data exist. The drug is present in animal milk; use during breastfeeding is not recommended [3].

Clinical Positioning Within Sleep Medicine

The 2023 AASM clinical practice guideline states: "We recommend orexin receptor antagonists (suvorexant, lemborexant) over benzodiazepine receptor agonists for chronic insomnia disorder in adults" [17]. This recommendation reflects the favorable next-morning cognitive and psychomotor profile demonstrated in SUNRISE-1 and the absence of rebound insomnia in SUNRISE-2.

Cognitive behavioral therapy for insomnia (CBT-I) remains the first-line treatment per AASM, the American College of Physicians, and the European Sleep Research Society [17][19]. Lemborexant is positioned as the preferred pharmacological option when CBT-I is not accessible, not effective, or not acceptable to the patient.

Comparison With Older Sleep Agents

Benzodiazepines such as temazepam act via GABA-A receptor positive allosteric modulation, producing global CNS depression that carries risks of dependence, next-day cognitive impairment, and rebound insomnia [9]. Non-benzodiazepine GABA modulators (zolpidem, eszopiclone) share most of those risks. Orexin antagonists instead reduce the active drive to wakefulness rather than globally suppressing brain activity, a mechanistic difference that accounts for the cleaner next-morning profile observed in SUNRISE-1 [7][6].

Real-World Use Data

Post-marketing data from insurance claims databases published between 2021 and 2024 suggest that lemborexant prescriptions have grown steadily since the 2020 launch, with most new prescriptions written by psychiatrists and primary care physicians [20]. The average fill duration in commercial insurance cohorts is approximately 3 months, shorter than the 12-month trial duration in SUNRISE-2. Whether shorter real-world use reflects patient preference, cost barriers, or prescriber hesitation is not clear from claims data alone.

Cost, Insurance Coverage, and Access Barriers

Lemborexant is a branded drug with no generic equivalent as of July 2025. Cash-pay cost at major U.S. Pharmacy chains ranges from approximately $350 to $450 for a 30-day supply. Most commercial insurance plans require a prior authorization, and many require step therapy through a generic benzodiazepine receptor agonist before approving lemborexant [21].

Manufacturer Patient Assistance

Eisai offers a co-pay card program for commercially insured patients. Patients without insurance may apply to Eisai's patient assistance program for free or reduced-cost drug. Eligibility criteria and program details are subject to change; prescribers should verify current availability at Eisai's official program portal.

Medicare Part D Coverage

Medicare Part D plans are not permitted to use manufacturer co-pay coupons to satisfy beneficiary cost-sharing. Lemborexant's tier placement on Part D formularies varies by plan year. Some Part D plans have placed lemborexant on a specialty tier with cost-sharing exceeding $100 per month, a significant barrier for fixed-income patients.