Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Dayvigo (Lemborexant). If you are concerned about side effects, discuss the risks and benefits of Dayvigo (Lemborexant) with your doctor.

The following side effects have been reported by at least 1% of people taking Dayvigo (Lemborexant). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• abnormal dreams
• back pain
• fatigue
• headache
• nausea
• nightmares
• sleepiness during the day
• sore throat
• stuffy or runny nose

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• anxiety
• changes in behaviour (e.g., aggressiveness, agitation)
• hallucinations while falling asleep or waking up
• memory loss
• signs of Depression or worsening signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
• sleep paralysis (e.g., temporarily unable to move or talk for several minutes while waking up)
• symptoms of a urinary tract infection (e.g. pain when urinating, urinating more often than usual, low back or flank pain)
• temporary weakness in the legs

Stop taking the medication and seek immediate medical attention if any of the following occur:

• doing activities while sleeping such as walking, cooking, eating, driving, or sexual activity
• thoughts of suicide or self-harm

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Dayvigo (Lemborexant).

5 mg
Each pale yellow, round, biconvex tablet, debossed with “5” on one side and “LeM” on the other side, contains 5 mg of Dayvigo (Lemborexant). Nonmedicinal ingredients: hydroxypropyl cellulose, lactose monohydrate, low-substituted hydroxypropyl cellulose, magnesium stearate; film coating: hypromellose 2910, polyethylene glycol 8000, talc, titanium dioxide and ferric oxide yellow.

10 mg
Each orange, round, biconvex tablet, debossed with “10” on one side and “LeM” on the other side, contains 10 mg of Dayvigo (Lemborexant). Nonmedicinal ingredients: hydroxypropyl cellulose, lactose monohydrate, low-substituted hydroxypropyl cellulose, magnesium stearate; film coating: hypromellose 2910, polyethylene glycol 8000, talc, titanium dioxide, ferric oxide yellow and ferric oxide red.

Do not take Dayvigo (Lemborexant) if you:

• are allergic to Dayvigo (Lemborexant) or any ingredients of the medication
• have Narcolepsy

There may be an interaction between Dayvigo (Lemborexant) and any of the following:

• alcohol
• Apalutamide
• Aprepitant
• anti-arrhythmic medications (e.g., Amiodarone, Dronedarone, quinidine)
• antihistamines (e.g,. cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• azelastine
• “azole” antifungals (e.g., fluconazole, itraconazole, ketoconazole, Voriconazole)
• benzodiazepines (e.g., Alprazolam, Diazepam, Lorazepam)
• Bicalutamide
• Bosentan
• brimonidine
• Buprenorphine
• Bupropion
• calcium channel blockers (e.g., Amlodipine, Diltiazem, Verapamil)
• cannabis
• chloral hydrate
• Clonidine
• Cimetidine
• ciprofloxacin
• Cobicistat
• conivaptan
• Cyclosporine
• Danazol
• Deferasirox
• efavirenz
• Elagolix
• Entacapone
• Enzalutamide
• etravirine
• Everolimus
• Fluvoxamine
• glecavir and pibrentasvir
• grazoprevir
• HIV protease inhibitors (atazanavir, darunavir, indinavir, lopinavir, nelfinavir, ritonavir)
• isoniazid
• kava kava
• Lomitapide
• lumacaftor and Ivacaftor
• macrolide antibiotics (e.g., clarithromycin, erythromycin)
• melatonin
• Metoclopramide
• mifepristone
• Mirtazapine
• Modafinil
• muscle relaxants (e.g., Baclofen, Cyclobenzaprine, methocarbamol, orphenadrine)
• Nabilone
• narcotic pain relievers (e.g., Codeine, Fentanyl, Morphine, Oxycodone)
• Pramipexole
• protein kinase inhibitors (e.g., Ceritinib, Dabrafenib, imatinib, Lapatinib, Nilotinib, Pazopanib)
• rifabutin
• rifampin
• Ropinirole
• Rotigotine
• St. John’s wort
• Sarilumab
• scopolamine
• seizure medications (e.g., Carbamazepine, Clobazam, , Levetiracetam, Phenobarbital, Phenytoin, primidone, Topiramate, Valproic acid, zonisamide)
• siltuximab
• stiripenntol
• Tapentadol
• Tocilizumab
• Tramadol
• tricyclic antidepressants (e.g., Clomipramine, Desipramine, Imipramine)
• Zolpidem
• Zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with Dayvigo (Lemborexant). Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the Nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Dayvigo (Lemborexant).

Alcohol and other medications that cause drowsiness: Do not combine Dayvigo (Lemborexant) with alcohol or other medications (e.g., antidepressants, sleeping pills, anxiety medications) that cause drowsiness since additional drowsiness can occur, which can be dangerous. Taking Dayvigo (Lemborexant) with other medications that cause drowsiness increases the likelihood of experiencing drowsiness or decreased alertness during the day.

Breathing: Like other medications that affect the nervous system, Dayvigo (Lemborexant) can suppress breathing. If you have Asthma, or another lung disease that increases your risk for breathing difficulties, discuss with your doctor how Dayvigo (Lemborexant) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Dayvigo (Lemborexant), and whether any special monitoring is needed.

Daytime drowsiness/reduced alertness: Even when taken at the lowest effective dose, Dayvigo (Lemborexant) may cause drowsiness or mental impairment in the daytime. The risk of daytime drowsiness is increased if Dayvigo (Lemborexant) is taken with less than a full night of sleep remaining (at least 7 hours). Avoid driving, operating machinery, or performing other tasks that require sound judgement until you have determined how you are affected by Dayvigo (Lemborexant).

Depression: Dayvigo (Lemborexant), like other medications to help with sleep, may cause mood swings and symptoms of depression, including thoughts of self-harm or suicide. If you have depression or a history of depression, discuss with your doctor how Dayvigo (Lemborexant) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Dayvigo (Lemborexant), and whether any special monitoring is needed. 

If you experience worsening or new symptoms of depression or such as poor concentration, changes in weight, changes in sleep, decreased interest in activities, or notice them in a family member who is taking Dayvigo (Lemborexant) contact your doctor as soon as possible.

Inappropriate Use: Like other medications for help with sleep problems, Dayvigo (Lemborexant) can be abused or used inappropriately. If you have a history of past or current Substance Use Problems you may be at greater risk of developing abuse or addiction while taking Dayvigo (Lemborexant).

Lactose: Dayvigo (Lemborexant) contains lactose. If you have hereditary problems of galactose intolerance, lactase deficiency, or glucose-galactose malabsorption, discuss the appropriateness of Dayvigo (Lemborexant) with your doctor.

Liver function:  Liver disease or reduced liver function may cause Dayvigo (Lemborexant) to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how Dayvigo (Lemborexant) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Dayvigo (Lemborexant), and whether any special monitoring is needed.

Memory disturbance: Medications such as Dayvigo (Lemborexant) can cause memory loss (amnesia). Amnesia of varying severity has been reported following normal doses of Dayvigo (Lemborexant).

Performing activities while not fully awake: People taking Dayvigo (Lemborexant) may perform activities such as sleepwalking, driving, preparing and eating food, and making phone calls while not fully awake and are unaware of their actions. The next morning, they may not remember what happened. This may be more likely to occur if you use alcohol or other sedative medications. If you discover this has happened to you, contact your doctor immediately.

Family members or caregivers of people who are taking Dayvigo (Lemborexant) should contact the person's doctor immediately if they notice any of these unusual behaviours.

Other sleep conditions: Dayvigo (Lemborexant) may cause episodes of sleep paralysis, an inability to move or speak when you are awakening. These episodes may last seconds to several minutes before normal movement is possible. 

Dayvigo (Lemborexant) has also been associated with muscle weakness and waking dreams, mental images that occur during the transition from sleep to wakefulness and also when falling asleep.

Pregnancy: Dayvigo (Lemborexant) should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Dayvigo (Lemborexant), contact your doctor immediately.

Breast-feeding: It is not known if Dayvigo (Lemborexant) passes into breast milk. If you are a breast-feeding mother and are taking Dayvigo (Lemborexant), it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Dayvigo (Lemborexant) have not been established for children.