Dayvigo (lemborexant) is a brand-name tablet that’s prescribed for insomnia. As with other drugs, Dayvigo can cause side effects, such as sleepiness.

Dayvigo belongs to a drug class called dual orexin receptor antagonists. The drug isn’t available in a generic version. Dayvigo is approved to treat insomnia in adults who have difficulty falling asleep or staying asleep.

Read on to learn about potential common, mild, and serious side effects of Dayvigo. For a general overview of the drug, including details about its uses, see this article.

Dayvigo can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Dayvigo in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Dayvigo use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Dayvigo’s prescribing information.

Mild side effects that have been reported with Dayvigo include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Dayvigo and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Dayvigo. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Dayvigo may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Dayvigo’s prescribing information.

If you develop serious side effects while taking Dayvigo, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

  • Sleep paralysis. Symptoms can occur when you’re falling asleep or waking up, and can include:
    • being unable to move or speak
    • sweating
    • difficulty breathing
  • Temporary muscle weakness, commonly in the leg. Symptoms can include muscle weakness that lasts from a few seconds to a few minutes.
  • Heart palpitations. Symptoms can include a:
    • sensation that your heart is pounding
    • fluttery feeling in your chest
  • Hallucinations that happen when you first fall asleep or wake up. These symptoms can include:
    • feeling like you’re falling or floating
    • sensing, seeing, or hearing things that aren’t real
  • Suicidal thoughts or behaviors. Symptoms can include:
    • changes in your mood or behavior
    • a loss of interest in your usual activities
    • sadness that doesn’t go away
  • Unusual sleep behaviors, such as sleepwalking.*
  • Severe allergic reaction.†

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Dayvigo. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Dayvigo may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Are there side effect reviews of Dayvigo?

Yes, there are side effect reviews. The manufacturer’s website has patient reviews that you can watch.

If you have questions about side effects with Dayvigo, talk with your doctor or pharmacist. They can provide more details about any side effects you may experience.

How do the side effects of Dayvigo compare with those seen with Ambien?

Dayvigo and Ambien (zolpidem)aredrugs prescribed to treat insomnia. Because of this, they may cause similar side effects. For example, both drugs can cause daytime sleepiness, headache, heart palpitations, and behavior changes.

However, they can also cause different side effects. In Ambien’s clinical trials, certain side effects were reported that didn’t occur with Dayvigo:

Can the different strengths, 5 mg and 10 mg, of Dayvigo cause different side effects?

No, different side effects weren’t reported at different strengths. However, some side effects may be more likely to occur with certain strengths. In clinical trials, headache was reported more by people who took 5 milligrams (mg) of Dayvigo. However, daytime sleepiness and nightmares were reported more often by people who took 10 mg of Dayvigo.

For more information about side effects and different strengths of Dayvigo, talk with your doctor.

Will Dayvigo make you feel “high”?

No, it’s not likely. Euphoria (feeling “high”) was not reported in Dayvigo’s clinical trials. If you notice mood or behavior changes while taking Dayvigo, let your doctor know. They may recommend a different treatment option for you.

Do Dayvigo side effects go away?

It’s possible. When you start taking a new medication, it can take time for your body to adjust.

If you notice side effects that become bothersome or don’t improve over time, talk with your doctor.

Learn more about some of the side effects that Dayvigo may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Dayvigo.

Excessive sleepiness, including daytime sleepiness

In Dayvigo’s clinical trials, excessive sleepiness was common. This includes daytime sleepiness, which was the most commonly reported side effect.

Dayvigo is meant to be taken at bedtime, at least 7 hours before you need to start your day. For this reason, you may feel sleepy the day after you take Dayvigo the night before. Symptoms can include sluggishness, fatigue, or not having enough energy to do your typical activities.

What you can do

Because of this possible side effect, you should avoid driving or operating heavy machinery until you know how Dayvigo affects you. In clinical trials, difficulty driving was more common in people who took 10 milligrams of Dayvigo. Do not take Dayvigo unless you have time to sleep for at least the next 7 hours. If you continue to experience daytime sleepiness after taking Dayvigo, talk with your doctor.

Nightmares or strange dreams

Nightmares or strange dreams were commonly reported in Dayvigo’s clinical trials. During a nightmare, you may experience:

What you can do

Talk with your doctor if you have nightmares or strange dreams that become troubling. To help prevent nightmares, you can exercise, meditate, and stick to a regular sleep schedule.

Headache

It’s possible to develop a headache while taking Dayvigo. In clinical trials, this was a commonly reported side effect. Symptoms can include:

  • pain in your neck, back, or around your head
  • dull or throbbing pain in your head

What you can do

To prevent headaches, you can try exercising, staying hydrated, or keeping a regular sleep schedule.

If you have headaches that worsen over time, talk with your doctor. They may recommend taking an over-the-counter pain reliever, such as Tylenol (acetaminophen) or Advil (ibuprofen).

Unusual sleep behaviors, such as sleepwalking

Medications that treat insomnia, such as Dayvigo, can cause unusual sleep behaviors. In addition to sleepwalking, these behaviors can include:

  • driving while asleep
  • cooking and eating food
  • making phone calls
  • having sex

What you can do

Because these activities happen when you’re asleep, you may not remember doing them the next morning. If you think you’ve experienced any of the behaviors listed above, talk with your doctor. They’ll likely recommend that you stop taking Dayvigo.

Allergic reaction

As with most drugs, Dayvigo can cause an allergic reaction in some people. However, this side effect wasn’t reported in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Dayvigo. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects if it’s safe to do so.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

Be sure to talk with your doctor about your health history before you take Dayvigo. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Suicidal thoughts and mental health conditions. Dayvigo can cause mood changes, including suicidal thoughts. If you have depression or another condition affecting your mood, talk with your doctor. Taking Dayvigo may worsen your condition. Also tell your doctor about any medications you may take to treat these conditions. They’ll decide whether Dayvigo is safe for you to take.

Allergic reaction. If you’ve had an allergic reaction to Dayvigo or any of its ingredients, your doctor will likely not prescribe Dayvigo. Ask your doctor what other medications may be better options for you.

Being an older adult. If you’re 65 years or older, you may have an increased risk of certain side effects from Dayvigo. This includes excessive sleepiness, particularly daytime sleepiness, which can cause difficulty driving. It can also increase your risk of falling and injury. For this reason, your doctor may recommend a different treatment for your insomnia. If they do prescribe Dayvigo, they’ll likely prescribe a lower dosage.

Daytime sleepiness. If you have a condition known as narcolepsy, taking Dayvigo may worsen it. With narcolepsy, people have difficulty staying awake during the day. Similarly, Dayvigo can cause excessive sleepiness, particularly daytime sleepiness. If you have narcolepsy, Talk with your doctor about treatment options for your insomnia.

Alcohol or substance misuse. Dayvigo is a controlled substance, meaning It carries the potential for misuse and psychological dependence. With dependence, your body needs the drug to function as usual. It’s possible to become dependent on a drug even if you take it exactly as prescribed. However, having a history of alcohol or substance misuse can increase this risk. For this this reason, you should not take Dayvigo if you have a history of substance misuse.

Lung or breathing problems. Dayvigo may cause respiratory depression, which is slow, shallow breathing. For this reason, If you have certain lung conditions, such as chronic obstructive pulmonary disease (COPD), let your doctor know. They’ll decide if Dayvigo is safe for you to take.

Liver problems. Dayvigo is broken down by the liver. Before starting treatment with this drug, tell your doctor if you have any liver problems. They may prescribe a lower dosage or recommend a different medication for your insomnia.

Alcohol with Dayvigo

You should not drink alcohol with Dayvigo. Doing so can increase your risk of certain side effects, such as memory problems, walking or coordination problems, and excessive sleepiness.

If you have questions about drinking alcohol taking Dayvigo, talk with your doctor or pharmacist.

Pregnancy and breastfeeding while taking Dayvigo

It’s unknown whether Dayvigo is safe to take during pregnancy. In animal studies, high doses of the drug caused fetal harm. However, it’s not known whether taking a recommended dose of Dayvigo would cause fetal harm. Additionally, animal studies don’t always predict what may happen in humans.

You and your doctor can decide whether it’s safe for you to take Dayvigo during pregnancy. If so, your doctor may enroll you in Dayvigo’s pregnancy registry by calling 888-274-2378. This registry collects information about any side effects experienced when taking Dayvigo during pregnancy.

Dayvigo passes into human breast milk. Children who are breastfed should be monitored for excessive sleepiness. Talk with your doctor to determine if Dayvigo is safe for you to take while breastfeeding.

Dayvigo, like other drugs, can cause side effects. The most common one is excessive sleepiness, particularly daytime sleepiness. If you’d like to learn more about Dayvigo, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Dayvigo. For details about other aspects of Dayvigo, refer to this article.
  • A look at insomnia. For details about insomnia, see our science of sleep hub.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.