Key takeaways:
Dayvigo (lemborexant) is a prescription sleep medication. It has several side effects to be aware of.
Common Dayvigo side effects include drowsiness, headaches, and strange dreams. These side effects are generally mild and can be managed at home.
Dayvigo can also cause nightmares, sleep paralysis, and hallucinations while falling asleep or waking up. These side effects can be frightening but are typically harmless.
Serious Dayvigo side effects include suicidal thoughts and abnormal sleep behaviors, such as sleepwalking. Talk to your prescriber if you experience serious side effects.
Getting enough sleep is a key part of staying healthy and feeling your best. But this can feel impossible when you’re living with insomnia. If practicing good sleep hygiene isn’t enough to help you rest, it may be time to think about trying a sleep medication.
Dayvigo (lemborexant) is a prescription medication that can help you fall asleep and stay asleep longer. Dayvigo is meant to be taken every night on a schedule. But some people take it only when needed.
While Dayvigo can help you get the rest you need, it can also cause some side effects. Understanding Dayvigo side effects can help you decide if it’s right for you and how to use it safely.
Dayvigo side effects at a glance
It’s good to know what to expect when taking Dayvigo. Here’s a quick look at the common and serious side effects experienced by people who took the medication in clinical trials.
Common or mild Dayvigo side effects include:
Drowsiness, including next-day drowsiness
Fatigue
Headache
Unusual dreams or nightmares
Less common but serious Dayvigo side effects include:
Daytime impairment
Sleep paralysis (not being able to move or speak while falling asleep or waking up)
Hallucinations (seeing or hearing things others don’t) while falling asleep or waking up
Cataplexy-like symptoms (sudden loss of muscle control)
Complex sleep behaviors, such as sleepwalking or sleep eating
Depression
Suicidal thoughts or behaviors
Most Dayvigo side effects are mild and can be managed at home. But some need to be evaluated by a healthcare professional. Below are more details about eight notable Dayvigo side effects and how to manage them.
1. Drowsiness
Feeling drowsy, fatigued, or sluggish is the most common Dayvigo side effect. Although it’s expected at bedtime, it can be disruptive when it hangs around after waking up. Taking the higher dose (10 mg) of Dayvigo raises your risk of this side effect.
There are a few things you can do to help minimize next-day drowsiness from Dayvigo:
Take Dayvigo right before going to bed.
Don’t take Dayvigo unless you plan on sleeping for at least 7 hours.
Avoid taking Dayvigo with meals or snacks. Dayvigo takes longer to start working if you’ve recently eaten. This means its effects will likely last longer than usual.
Is Dayvigo a controlled substance? Read pharmacists’ answers to this and other frequently asked questions about Dayvigo (lemborexant).
Beating insomnia: Learn about experiences with insomnia and how three people were able to get the sleep they needed.
Dayvigo vs. Quviviq: Learn how Dayvigo compares with Quviviq (daridorexant), a similar sleep medication.
Don’t drive or perform other activities that require alertness until you know how Dayvigo affects you.
2. Daytime impairment
Next-day drowsiness from Dayvigo is usually mild and can be managed with the tips listed above. But for some people, this side effect can be severe, even when you take Dayvigo as prescribed.
Dayvigo (especially the 10 mg dose) can sometimes cause daytime impairment. This is a more severe form of drowsiness that also affects your physical abilities, like balance, coordination, and reaction time. It can put you at risk for injuries or falls and make it difficult to perform even simple tasks.
Taking Dayvigo with other substances or medications that cause drowsiness raises your risk of daytime impairment. Don’t take Dayvigo with other sleeping medications or sleep aids. And don’t drink alcohol if you plan on taking Dayvigo. Even small amounts of alcohol can raise your risk of experiencing severe impairment.
3. Headache
Headache is a possible Dayvigo side effect. Generally, this side effect isn’t severe enough for people to stop taking Dayvigo.
If Dayvigo causes headaches, consider these tips to help manage them:
Drink extra water or fluids.
Rest in a dark or quiet space if possible.
Apply an ice pack to your head.
Ask a healthcare professional if you can safely take over-the-counter pain relievers, such as ibuprofen (Motrin, Advil).
If your headache doesn’t get better or feels severe, tell your prescriber. Dayvigo may not be the best option for you.
4. Unusual dreams or nightmares
Dayvigo can cause unusual dreams or nightmares. Some people might experience more intense or vivid dreams, which can be unsettling. While this Dayvigo side effect is uncomfortable, it isn’t dangerous.
If these Dayvigo side effects are disturbing or affect your sleep quality, it might help to maintain a relaxing bedtime routine. Other tips for good sleep include avoiding heavy meals or caffeine before bedtime and creating a calm, dark sleep environment.
If unusual dreams or nightmares become a significant concern, talk to your prescriber. They may have additional advice for managing this Dayvigo side effect. They might also suggest trying a different sleep medication.
5. Sleep paralysis
Dayvigo can sometimes cause sleep paralysis. This is when you feel awake but are unable to move or speak. It can last just a few seconds or for several minutes. Then you wake up or fall asleep naturally.
Less commonly, Dayvigo can also cause hallucinations when drifting to sleep or waking up. During the transition between sleep and wake, you may see or feel something that others don’t. These types of hallucinations happen when your brain is transitioning between wakefulness and sleep. They aren’t related to mental health conditions.
Although they can be concerning, these Dayvigo side effects are generally harmless. If you experience sleep paralysis, try to stay calm and remember that it will pass. Talk to your prescriber if you experience sleep paralysis or hallucinations. They may prefer you to take another sleep medication.
6. Loss of muscle control
Rarely, Davigo can cause sudden loss of muscle control (cataplexy-like symptoms). This typically occurs as leg weakness, and it can happen at any time of day. This Dayvigo side effect is temporary and lasts from a few seconds to a few minutes.
If you experience this, sit down or remain in a safe position to prevent injury. Tell your prescriber if you have sudden muscle weakness while taking Dayvigo. This medication might not be right for you.
7. Sleepwalking
Like other sleep medications, Dayvigo can cause sleepwalking and other abnormal sleep behaviors. There are reports of people performing complex activities while not fully awake, including eating, cooking, or making phone calls. You’re not usually aware you’re doing these activities and typically have no memory of them afterward.
This rare but serious Dayvigo side effect can happen even if you’ve been taking it for a while without issues. If you experience sleepwalking or other abnormal sleep behaviors, stop taking Dayvigo, and tell your prescriber. Abnormal sleep behaviors can be dangerous to you and the people around you.
8. Suicidal thoughts
Rarely, Dayvigo can cause or worsen depression or suicidal thoughts. During clinical trials, people taking Dayvigo reported having more thoughts of self-harm than people taking a placebo (a pill containing no medication).
This rare but serious Dayvigo side effect should be evaluated by a healthcare professional right away. Tell your prescriber about any changes in your mood or behavior. You’ll likely need to stop taking Dayvigo if you experience this side effect.
If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.
Frequently asked questions
No, Dayvigo isn’t known to cause changes to your body weight. This includes weight loss and weight gain. But in general, getting enough good-quality sleep can help you maintain a body weight that’s comfortable for you.
Dayvigo side effects are usually strongest shortly after taking it and while waking up. They should fade during the day. But this isn’t the case for everyone who takes it. Dayvigo can sometimes cause next-day drowsiness and impairment that can last for several days. The risk of this goes up if you’re taking the higher dose (10 mg) of Dayvigo.
No, Dayvigo isn’t known to cause changes to your body weight. This includes weight loss and weight gain. But in general, getting enough good-quality sleep can help you maintain a body weight that’s comfortable for you.
Dayvigo side effects are usually strongest shortly after taking it and while waking up. They should fade during the day. But this isn’t the case for everyone who takes it. Dayvigo can sometimes cause next-day drowsiness and impairment that can last for several days. The risk of this goes up if you’re taking the higher dose (10 mg) of Dayvigo.
The bottom line
Dayvigo (lemborexant) can be a helpful medication for insomnia, but it does have some side effects. Common Dayvigo side effects include drowsiness, headaches, and strange dreams. These side effects are generally mild and can be managed at home. Dayvigo can also cause nightmares, sleep paralysis, and hallucinations while falling asleep or waking up. These side effects can seem scary, but they’re generally harmless.
Rare but serious Dayvigo side effects include suicidal thoughts and abnormal sleep behaviors, such as sleepwalking. If you experience these side effects, stop taking Dayvigo and contact your prescriber right away.
Why trust our experts?
References
Canadian Agency for Drugs and Technology in Health. (2023). Lemborexant (Dayvigo): CADTH reimbursement review. National Center for Biotechnology Information.
Eisai. (2025). Dayvigo- lemborexant tablet, film coated [package insert].
Mayleben, D., et al. (2021). Assessment of morning sleep propensity with lemborexant in adults with insomnia disorder in a randomized, placebo-controlled crossover study. Sleep Advances.
Rhodes, M. A. (2021). Lemborexant (Dayvigo) for the treatment of insomnia. American Family Physician.
Roberts, T., et al. (2023). Acute emergence of suicidal thoughts following lemborexant initiation: An adverse reaction case report. CNS Spectrums.
Shibata, S., et al. (2022). Narcolepsy-like symptoms triggered by lemborexant in the context of hyperactive delirium in a patient with bipolar depression: A case report. Journal of Clinical Sleep Medicine.
Waters, F., et al. (2016). What is the link between hallucinations, dreams, and hypnagogic-hypnopompic experiences? Schizophrenia Bulletin.
