What to Know About Dayvigo (Lemborexant)

An Orexin Antagonist Drug Used to Treat Insomnia

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Dayvigo (lemborexant) is a prescription sleep medication used for the treatment of insomnia. It is unique as a dual orexin receptor antagonist (DORA) drug that acts as a central nervous system depressant.

Dayvigo binds to both the orexin-1 and orexin-2 receptors in the brain. Orexin receptors normally respond to orexin neurotransmitters and are important to the waking part of the sleep-wake cycle. When blocked by Dayvigo, these receptors become less active, allowing for better sleep at night.

Dayvigo is restricted as a schedule IV (CIV) drug, meaning that it is a controlled substance. It requires a prescription from a doctor. Even though its use is controlled, it has a lower likelihood of abuse compared to other controlled substances with lower schedule numbers. 

Dayvigo comes in a tablet form and is taken once at night close to your intended bedtime. Dayvigo is the branded form of lemborexant. There is currently no generic form of lemborexant available in the US, with the drug patent not set to expire until 2035.

Ailing Woman Rests in Bed
Grace Cary / Getty Images


Dayvigo is approved by the U.S. Food and Drug Administration (FDA) to treat insomnia. This condition is often associated with difficulty initiating or maintaining sleep, or sleep that is not refreshing in the absence of another sleep disorder (such as sleep apnea, restless legs syndrome, or narcolepsy). Insomnia may cause other symptoms, including:

  • Fatigue
  • Decreased energy
  • Poor concentration
  • Mood problems (anxiety or depression)
  • Headache or pain complaints
  • Malaise (generally feeling unwell)
  • Upset stomach (dyspepsia)

Insomnia is the most common sleep disorder, affecting about 10% of the population. People who experience chronic sleeplessness due to insomnia may be able to optimize their ability to fall or stay asleep by taking Dayvigo before going to bed.

Before Taking

When difficulty sleeping persists, it is natural to seek treatment. After home remedies have been exhausted, this may lead to a conversation with a primary care provider or a referral to a board-certified sleep physician.

The doctor may ask questions about insomnia, trying to understand about environmental factors (often noise, light, and temperature of the bedroom environment), physical factors (such as risk factors for coexisting conditions like sleep apnea), and behavioral factors (role of stress, exercise or activity levels, or screen use before bedtime). 

The American College of Physicians, the national board of internal medicine doctors, recommends cognitive behavioral therapy for insomnia (CBTI) as the first-line treatment for chronic insomnia. This may be done with the help of a psychologist or sleep specialist, in a class, online, or with a book.

In some cases, medication is required to resolve difficulties in sleeping. Drugs used to treat insomnia vary in purpose (short-term vs. long-term), drug class, potential drug interactions, and side effects. It may be necessary to try several treatments before settling on the right one. A novel treatment, such as the use of Dayvigo, may be helpful.

Precautions and Contraindications

People with impaired liver function may need to reduce the dose of Dayvigo. In the case of severe hepatic impairment (liver failure), it should be avoided entirely. A weakened ability to eliminate the drug from the body can increase the frequency of side effects as Dayvigo lingers, potentially causing daytime sleepiness the following day.

Dayvigo has not yet been tested in pregnant women. For this reason, it is recommended that use be avoided during pregnancy.

In animal tests, lemborexant was present in breast milk after being taken. Impacts of Dayvigo on development or behavior in babies has not been studied. Babies who may have ingested Dayvigo through breast milk should be monitored closely for any sedative effects (increased sleeping, decreased responsiveness, changes in breathing, etc.).

Other Orexin Antagonists

Another orexin receptor blocking drug used to treat insomnia is Belsomra (suvorexant). This drug has similar effects and side effects to Dayvigo.


Dayvigo comes in 5 and 10 milligram (mg) tablets. The standard dosage is 5 mg. However, it may be increased in consultation with the prescribing provider if it is believed that the ability to sleep could benefit from the increase and the risks associated with the higher dose are tolerable.

All listed dosages are according to the drug manufacturer. Never change a medication dose or frequency without discussing this with the prescribing doctor. Review the documentation accompanying the prescription and talk to the doctor to make sure the dose is proper.


People who are older than age 65 are advised by Dayvigo’s manufacturers not to take a dose higher than 5 mg.

How to Take and Store

Dayvigo should be taken close to bedtime and with the intent to sleep for at least seven hours. Taking Dayvigo with a meal or immediately after a meal can delay its effects.

There are no immediate consequences of missing a dose of Dayvigo. However, the return of insomnia and sleep loss may increase the chances of side effects once taking Dayvigo again. Dayvigo is most effective, and the least disruptive, when taken once per night on a continuous basis.

There is no effective treatment for overdose. However, the main outcome of Dayvigo overdose in studies using doses up to 75 mg was simply an increase in the risk of daytime sleepiness and similar side effects. The side effects may not be dramatic, but being in a state of fatigue and frequently losing consciousness can put you at risk of self-injury, especially if driving. 

If you have overdosed on Dayvigo, seek help getting medical attention. Do not drive yourself anywhere. Once you are in a medical setting, you will be monitored to make sure you fully recover. Unlike some drugs, Dayvigo is not easily flushed from your body, so it will need to be metabolized over time.

Dayvigo should be stored at room temperature (68 F to 77 F). Doctors may prescribe small quantities of Dayvigo at a time to minimize the risk of abuse and maintain communication about Dayvigo’s effectiveness and any potential side effects. It may require closer follow up when it is started, and annual visits subsequently once the therapy is established.

Side Effects

Daytime sleepiness or fatigue occur in some people who take Dayvigo. Side effects can be more likely to occur if Dayvigo is taken in a high dose, in combination with other CNS depressants, or after a night of poor sleep.

Around 1 in 20 people taking 5 mg of Dayvigo experience daytime sleepiness or similar side effects, while 1 in 10 people taking 10 mg of Dayvigo experience them.

There is a dose-dependent decrease in balance, memory, and attention for the four hours after taking Dayvigo. Therefore, it should only be taken right before going to sleep. The impacts on balance and memory are increased if alcohol and Dayvigo are taken together, and this is discouraged. 

Less common side effects include:

  • Sleep paralysis (inability to move during sleep-wake transition, often associated with hallucinations)
  • Cataplexy (temporary loss of muscle strength, usually affecting the limbs)

These symptoms are often associated with narcolepsy, and since this condition is caused by a loss of neurons in the brain’s hypothalamus that secrete orexin, this is a logical association.


Complex sleep behaviors, defined as sleepwalking (somnambulism) and other unconscious activities, are a serious side effect to Dayvigo. If someone experiences complex sleep behaviors while taking Dayvigo, it should be stopped to prevent harm.

A small number of people taking Dayvigo experience worsened depression or suicidal ideation, especially when taken in excess of their required dose. If taking Dayvigo, and an onset of new or worsened depressive thoughts occurs, contact the prescribing doctor as soon as possible to consider changing dosage or medication.

If you are having suicidal thoughts, dial 988 to contact the 988 Suicide & Crisis Lifeline and connect with a trained counselor. If you or a loved one are in immediate danger, call 911.

Warnings and Interactions

Dayvigo should not be taken by someone with narcolepsy

People taking Dayvigo should not operate vehicles or heavy machinery while the medication is in their system, especially if they have experienced side effects of drowsiness or lack of focus when taking the medication.

Clinical studies have found that people taking the higher dose (the 10 mg Dayvigo tablet), or those who exceed their normal dose, may have an impaired ability to operate vehicles or other machinery. It may impair tasks that require focus.

Importantly, lack of sleep the night before taking Dayvigo can increase the risk of impaired alertness the morning after.

Some individuals with genetic changes affecting their ability to metabolize certain drugs that would normally be cleared by the liver may be at higher risk of side effects. Cytochrome P450, also called CYP3A, is a group of genes that code for enzymes often involved in the metabolism of drugs. In addition, drugs that alter CYP3A can negatively interact with Dayvigo.

Medications that are moderate and strong CYP3A inhibitors can increase the side effects of Dayvigo. Moderate and strong CYP3A inhibitors include anti-fungal, antibiotic, and anti-hypertensive medications, including:

  • Fluconazole
  • Itraconazole
  • Clarithromycin
  • Verapamil

Dayvigo’s manufacturer suggests that weak CYP3A inhibitors such as the muscle relaxant chlorzoxazone or ranitidine(sold as Zantac and used for heartburn or GERD) may be taken with a 5 mg dose of Dayvigo.

Moderate and strong CYP3A inducers may weaken the desired effect of Dayvigo. Moderate and strong CYP3A inducers include:

  • Rifampin
  • Carbamazepine
  • St. John’s wort
  • Bosentan
  • Efavirenz
  • Etravirine
  • Modafinil

Dayvigo has not yet been studied for use in moderate to severe obstructive sleep apnea (OSA), even though this condition may be associated with sleep fragmentation and insomnia. It is unknown if there are benefits or risks associated with taking Dayvigo with OSA.

Taking doses beyond the maximum recommended dose (10 mg) can have sedative-like effects and can lead to the potential for abuse. Physical dependence, withdrawal, or addiction to Dayvigo have not been observed in studies.

A Word From Verywell

If you are experiencing difficulties with insomnia, seek evaluation by a board-certified sleep physician. It may be important to rule out other potential causes of the condition, including sleep apnea.

Although cognitive behavioral therapy for insomnia (CBTI) may be recommended as the initial treatment, in some cases the long-term use of a prescription medication may be necessary. Dayvigo may have a role to ease insomnia in people who experience an ongoing problem.

1 Source
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Qaseem A, et al. Management of chronic insomnia disorder in adults: a clinical practice guideline from the American College of PhysiciansAnn Intern Med. 2016;165(2):125-133.

Additional Reading

By Brandon Peters, MD
Brandon Peters, MD, is a board-certified neurologist and sleep medicine specialist.