Last updated on RxList: 4/12/2021
Belsomra Side Effects Center

What Is Belsomra?

Belsomra (suvorexant) is a selective antagonist for orexin receptors OX1R and OX2R used to treat insomnia characterized by difficulties with sleep onset and/or sleep maintenance.

What Are Side Effects of Belsomra?

Common side effects of Belsomra include:

  • headache,
  • sleepiness,
  • next day drowsiness,
  • dizziness,
  • abnormal dreams,
  • diarrhea,
  • dry mouth,
  • cough, and
  • upper respiratory tract infection

Belsomra may cause serious side effects that you may not know are happening to you, including "sleep-walking" or doing other activities when you are asleep like eating, talking, having sex, or driving a car. Call your doctor right away if you find out you have done any of these activities after taking Belsomra.

Dosage for Belsomra

The recommended dose for Belsomra is 10 mg, taken no more than once per night and within 30 minutes of going to bed, with at least 7 hours remaining before the planned time of awakening.

What Drugs, Substances, or Supplements Interact with Belsomra?

Belsomra may interact with alcohol, azole antifungals, antibiotics, nefazodone, antiretrovirals, conivaptan, aprepitant, diltiazem, grapefruit juice, imatinib, verapamil, rifampin, carbamazepine, phenytoin, and digoxin. Tell your doctor all medications and supplements you use.

Belsomra During Pregnancy and Breastfeeding

During pregnancy, Belsomra should be taken only if prescribed. This drug passes into breast milk. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Additional Information

Our Belsomra (suvorexant) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Belsomra Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Some people using this medicine have engaged in activity while not fully awake and later had no memory of it. This may include walking, driving, eating, having sex, or making phone calls. If this happens to you, call your doctor right away.

Call your doctor at once if you have:

  • trouble moving or talking when you first wake up;
  • a weak feeling in your legs;
  • unusual thoughts or behavior;
  • anxiety, agitation, depression;
  • memory problems;
  • confusion, hallucinations; or
  • thoughts about hurting yourself.

You may be more likely to have side effects if you are overweight.

Common side effects may include:

  • strange dreams; or
  • drowsiness during the day after taking suvorexant.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Belsomra (Suvorexant Tablets)


Sleep Disorders: Foods That Help Sleep or Keep You Awake See Slideshow
Belsomra Professional Information


The following serious adverse reactions are discussed in greater detail in other sections:

  • CNS Depressant Effects and Daytime Impairment [see WARNINGS AND PRECAUTIONS]
  • Worsening of Depression/Suicidal Ideation [see WARNINGS AND PRECAUTIONS]
  • Complex Sleep Behaviors [see WARNINGS AND PRECAUTIONS]
  • Sleep Paralysis, Hypnagogic/Hypnopompic Hallucinations, Cataplexy-Like Symptoms [see WARNINGS AND PRECAUTIONS]
  • Patients with Compromised Respiratory Function [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

In 3-month controlled efficacy trials (Study 1 and Study 2), 1263 patients were exposed to BELSOMRA including 493 patients who received BELSOMRA 15 mg or 20 mg (see Table 1).

In a long-term study, additional patients (n=521) were treated with BELSOMRA at higher than recommended doses, including a total of 160 patients who received BELSOMRA for at least one year.

Table 1: Patient Exposure to BELSOMRA 15 mg or 20 mg in Study 1 and Study 2

Patients Treated BELSOMRA 15 mg BELSOMRA 20 mg
For ≥ 1 Day (n) 202 291
Men (n) 69 105
Women (n) 133 186
Mean Age (years) 70 45
For ≥ 3 Months (n) 118 172

The pooled safety data described below (see Table 2) reflect the adverse reaction profile during the first 3 months of treatment.

Adverse Reactions Resulting In Discontinuation Of Treatment

The incidence of discontinuation due to adverse reactions for patients treated with 15 mg or 20 mg of BELSOMRA was 3% compared to 5% for placebo. No individual adverse reaction led to discontinuation at an incidence ≥1%.

Most Common Adverse Reactions

In clinical trials of patients with insomnia treated with BELSOMRA 15 mg or 20 mg, the most common adverse reaction (reported in 5% or more of patients treated with BELSOMRA and at least twice the placebo rate) was somnolence (BELSOMRA 7%; placebo 3%).

Table 2 shows the percentage of patients with adverse reactions during the first three months of treatment, based on the pooled data from 3-month controlled efficacy trials (Study 1 and Study 2).

At doses of 15 or 20 mg, the incidence of somnolence was higher in females (8%) than in males (3%). Of the adverse reactions reported in Table 2, the following occurred in women at an incidence of at least twice that in men: headache, abnormal dreams, dry mouth, cough, and upper respiratory tract infection.

The adverse reaction profile in elderly patients was generally consistent with non-elderly patients. The adverse reactions reported during long-term treatment up to 1 year were generally consistent with those observed during the first 3 months of treatment.

Table 2: Percentage of Patients with Adverse Reactions Incidence ≥2% and Greater than Placebo in 3-Month Controlled Efficacy Trials (Study 1 and Study 2)

Placebo BELSOMRA (20 mg in non-elderly or 15 mg in elderly patients)
n=767 n=493
Gastrointestinal Disorders
Diarrhea 1 2
Dry mouth 1 2
Infections and Infestations
Upper respiratory tract infection 1 2
Nervous System Disorders
Headache 6 7
Somnolence 3 7
Dizziness 2 3
Psychiatric Disorders
Abnormal dreams 1 2
Respiratory, Thoracic and Mediastinal Disorders
Cough 1 2

Dose Relationship For Adverse Reactions

There is evidence of a dose relationship for many of the adverse reactions associated with BELSOMRA use, particularly for certain CNS adverse reactions.

In a placebo-controlled crossover study (Study 3), non-elderly adult patients were treated for up to one month with BELSOMRA at doses of 10 mg, 20 mg, 40 mg (2 times the maximum recommended dose) or 80 mg (4 times the maximum recommended dose). In patients treated with BELSOMRA 10 mg (n=62), the types of adverse reactions observed were similar to those observed in patients treated with BELSOMRA 20 mg. BELSOMRA was associated with a dose-related increase in somnolence: 2% at the 10 mg dose, 5% at the 20 mg dose, 12% at the 40 mg dose, and 11% at the 80 mg dose, compared to <1% for placebo. BELSOMRA was also associated with a dose-related increase in serum cholesterol: 1 mg/dL at the 10 mg dose, 2 mg/dL at the 20 mg dose, 3 mg/dL at the 40 mg dose, and 6 mg/dL at the 80 mg dose after 4 weeks of treatment, compared to a 4 mg/dL decrease for placebo.

Insomnia Study In Patients With Mild To Moderate Alzheimer's Disease

In a 4-week insomnia study of BELSOMRA in 285 patients (BELSOMRA n=142; placebo n=143) with mild to moderate Alzheimer's Disease, the adverse reactions occurring ≥2% and greater than placebo were somnolence (4% compared to 1% for placebo), dry mouth (2% compared to 1% for placebo), and falls (2% compared to 0% for placebo) [see Clinical Studies].

Post-Marketing Experience

The following adverse reactions have been identified during post-approval use of BELSOMRA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiac disorders: palpitations, tachycardia

Gastrointestinal disorders: nausea, vomiting

Nervous system disorders: psychomotor hyperactivity

Psychiatric disorders: anxiety

Skin and subcutaneous tissue disorders: pruritus


CNS-Active Agents

When BELSOMRA was co-administered with alcohol, additive psychomotor impairment was demonstrated. There was no alteration in the pharmacokinetics of BELSOMRA [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Effects Of Other Drugs On BELSOMRA

Metabolism by CYP3A is the major elimination pathway for suvorexant.

CYP3A Inhibitors

Concomitant use of BELSOMRA with strong inhibitors of CYP3A (e.g., ketoconazole, itraconazole, posaconazole, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, boceprevir, telaprevir, telithromycin and conivaptan) is not recommended [see CLINICAL PHARMACOLOGY].

The recommended dose of BELSOMRA is 5 mg in subjects receiving moderate CYP3A inhibitors (e.g., amprenavir, aprepitant, atazanavir, ciprofloxacin, diltiazem, erythromycin, fluconazole, fosamprenavir, grapefruit juice, imatinib, verapamil). The dose generally should not exceed 10 mg in patients receiving moderate CYP3A inhibitors [see CLINICAL PHARMACOLOGY].

CYP3A Inducers

Suvorexant exposure can be substantially decreased when co-administered with strong CYP3A inducers (e.g., rifampin, carbamazepine and phenytoin). The efficacy of BELSOMRA may be reduced [see CLINICAL PHARMACOLOGY].

Effects Of BELSOMRA On Other Drugs


Concomitant administration of BELSOMRA with digoxin slightly increased digoxin levels due to inhibition of intestinal P-gp. Digoxin concentrations should be monitored when co-administering BELSOMRA with digoxin [see CLINICAL PHARMACOLOGY].

Read the entire FDA prescribing information for Belsomra (Suvorexant Tablets)

© Belsomra Patient Information is supplied by Cerner Multum, Inc. and Belsomra Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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