Suvorexant

The mechanism of action of suvorexant in the treatment of insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system plays a role in wakefulness.

• BELSOMRA ® (suvorexant) is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance. BELSOMRA is an orexin receptor antagonist indicated for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance ( 1 ).ICD-10: G47.00

• BELSOMRA is contraindicated in patients with narcolepsy. BELSOMRA is contraindicated in patients with narcolepsy ( 4 ).contraindicated

Use the lowest dose effective for the patient ( 2.1 ). Recommended dose is 10 mg, no more than once per night taken within 30 minutes of going to bed, with at least 7 hours remaining before the planned time of awakening. If the 10 mg dose is well-tolerated but not effective, the dose can be increased, not to exceed 20 mg once daily ( 2.1 , 2.2 ). Time to effect may be delayed if taken with or soon after a meal ( 2.1 ). 2.1 Dosing Information Use the lowest dose effective for the patient. For all BELSOMRA doses, take no more than once per night within 30 minutes of going to bed (with at least 7 hours remaining prior to planned awakening). Time to effect of BELSOMRA may be delayed if taken with or soon after a meal [see Clinical Pharmacology (12.3) ]. The recommended dose for BELSOMRA is 10 mg, taken no more than once per night. If the 10 mg dose is well-tolerated but not effective, the dose can be increased. The maximum recommended dose of BELSOMRA is 20 mg taken no more than once per night. 2.2 Special Populations Exposure to BELSOMRA is increased in obese compared to non-obese patients, and in women compared to men. Particularly in obese women, the increased risk of exposure-related adverse effects should be considered before increasing the dose [see Clinical Pharmacology (12.3) ] . 2.3 Use with CNS Depressants When BELSOMRA is combined with other CNS depressant drugs, dosage reduction of BELSOMRA and/or the other drug(s) may be necessary because of potentially additive effects [see Warnings and Precautions (5.1) ] .

CNS Depressant Effects and Daytime Impairment: Risk of impaired alertness and motor coordination, including impaired driving; risk increases with dose; caution patients taking 20 mg against next-day driving and other activities requiring complete mental alertness ( 5.1 ). Worsening of Depression/Suicidal Ideation: Worsening of depression or suicidal thinking may occur. Risk increases with dose. Immediately evaluate any new behavioral changes ( 5.2 ). Complex Sleep Behaviors: Behaviors including sleep-walking, sleep-driving, and engaging in other activities while not fully awake may occur. Discontinue immediately if a complex sleep behavior occurs ( 5.3 ). Sleep Paralysis, Hypnagogic/Hypnopompic Hallucinations, and Cataplexy-like Symptoms: May occur with the use of BELSOMRA. Risk increases with dose ( 5.4 ). Compromised Respiratory Function: Effect on respiratory function should be considered ( 5.5 , 8.6 ). Need to Evaluate for Co-morbid Diagnoses: Reevaluate if insomnia persists after 7 to 10 days of treatment ( 5.6 ). 5.1 CNS Depressant Effects and Daytime Impairment BELSOMRA is a central nervous system (CNS) depressant that can impair daytime wakefulness even when used as prescribed. Prescribers should monitor for somnolence and CNS depressant effects, but impairment can occur in the absence of symptoms, and may not be reliably detected by ordinary clinical exam (i.e., less than formal testing of daytime wakefulness and/or psychomotor performance). CNS depressant effects may persist in some patients for up to several days after discontinuing BELSOMRA.

The following serious adverse reactions are discussed in greater detail in other sections: CNS Depressant Effects and Daytime Impairment [see Warnings and Precautions (5.1) ] Worsening of Depression/Suicidal Ideation [see Warnings and Precautions (5.2) ] Complex Sleep Behaviors [see Warnings and Precautions (5.3) ] Sleep Paralysis, Hypnagogic/Hypnopompic Hallucinations, Cataplexy-Like Symptoms [see Warnings and Precautions (5.4) ] Patients with Compromised Respiratory Function [see Warnings and Precautions (5.5) ] The most common adverse reaction (reported in 5% or more of patients treated with BELSOMRA and at least twice the placebo rate) with BELSOMRA was somnolence ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Merck Sharp & Dohme LLC at 1-877-888-4231 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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.

Patients with severe hepatic impairment: Not recommended ( 8.7 ). 8.1 Pregnancy Risk Summary Available data from postmarketing reports with BELSOMRA use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, oral administration of suvorexant to pregnant rats and rabbits during the period of organogenesis decreased maternal body weight and/or weight gain at doses ≥ 30 and 28 times the maximum recommended human dose (MRHD) of 20 mg based on AUC in the rat and rabbit, respectively. Suvorexant caused decreased fetal weight at doses ≥ 86 times the MRHD based on AUC in the rat and did not cause significant fetal toxicity at doses up to 28 times the MRHD based on AUC in the rabbit. The no observed adverse effect levels (NOAELs) for fetal toxicity are 25 and 28 times the MRHD based on AUC in the rat and rabbit, respectively. Oral administration of suvorexant to pregnant rats during pregnancy and lactation caused decreased maternal and pup body weight or weight gain at approximately 48 times the MRHD based on AUC. The NOAEL for development toxicity in the rat is 25 times the MRHD based on AUC (see Data ) . The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.

Metabolism

Suvorexant exposure increases in a less than strictly dose-proportional manner over the range of 10-80 mg because of decreased absorption at higher doses. Suvorexant pharmacokinetics are similar in healthy subjects and patients with insomnia.

There is limited premarketing clinical experience with an overdosage of BELSOMRA. In clinical pharmacology studies, healthy subjects who were administered morning doses of up to 240 mg of suvorexant showed dose-dependent increases in the frequency and duration of somnolence. General symptomatic and supportive measures should be used, along with immediate gastric lavage where appropriate. Intravenous fluids should be administered as needed. As in all cases of drug overdose, vital signs should be monitored and general supportive measures employed. The value of dialysis in the treatment of overdosage has not been determined. As suvorexant is highly protein-bound, hemodialysis is not expected to contribute to elimination of suvorexant. As with the management of all overdosage, the possibility of multiple drug ingestion should be considered. Consider contacting a poison control center for up-to-date information on the management of hypnotic drug product overdosage.

• Aug 13, 2014NDANDA204569Merck Sharp Dohme

1. 1Drug Ineffective3,01324%
2. 2Nightmare7385.8%
3. 3Somnolence7295.7%
4. 4Insomnia6765.3%
5. 5Abnormal Dreams6004.7%
6. 6Headache5414.2%
7. 7Feeling Abnormal4863.8%
8. 8Nausea3843.0%
9. 9Hallucination3732.9%
10. 10No Adverse Event3632.8%
11. 11Fatigue3562.8%
12. 12Dizziness3282.6%
13. 13Anxiety3122.4%
14. 14Fall2642.1%
15. 15Off Label Use2622.0%

The 10 most recently updated of 68 ClinicalTrials.gov registrations naming Suvorexant as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Suvorexant and Alcohol
  Recruiting · Early phase 1 · Interventional · 30 enrolled · William Stoops
  NCT06326684updated 2026-06-08
• The Effects of Orexin Antagonism on Fear Extinction in PTSD
  Not yet recruiting · Phase 4 · Interventional · 40,120 enrolled · VA Office of Research and Development
  NCT06788522updated 2026-06-02
• Orexin s Role in the Neurobiology of Substance Use Disorder
  Recruiting · Interventional · 140 enrolled · National Institute on Drug Abuse (NIDA)
  NCT05630781updated 2026-05-28
• A Study of Suvorexant (MK-4305) for the Treatment of Insomnia Disorder in Participants With Opioid Use Disorder (MK-4305-098)
  Recruiting · Phase 3 · Interventional · 300 enrolled · Merck Sharp & Dohme LLC
  NCT06655883updated 2026-05-15
• Suvorexant for Alcohol Use Disorder (AUD): Neural Mechanisms
  Recruiting · Phase 1 · Phase 2 · Interventional · 180 enrolled · National Institute on Alcohol Abuse and Alcoholism (NIAAA)
  NCT06484075updated 2026-05-15
• Treating Insomnia and Improving Metabolic Health in Midlife Women With Insomnia
  Completed · Phase 4 · Interventional · 31 enrolled · Brigham and Women's Hospital
  NCT05593653updated 2026-04-16
• Trial of Suvorexant for Sleep in Children With Autism
  Recruiting · Phase 2 · Interventional · 26 enrolled · Stanford University
  NCT05546554updated 2026-03-27
• Double-blind Randomized Controlled Trial Comparing Suvorexant 20 mg to Placebo for Treatment of Insomnia in Cancer Survivors
  Terminated · Phase 4 · Interventional · 5 enrolled · Medical University of South Carolina
  NCT06162663updated 2026-02-27
• Measuring Acute Drug Demand in Humans
  Suspended · Early phase 1 · Interventional · 75 enrolled · University of Maryland, Baltimore
  NCT05829655updated 2026-02-18
• Evaluation of Suvorexant for Reduction of Brain Reactivity in Patients With Cannabis Use Disorder (Pilot Study)
  Recruiting · Phase 4 · Interventional · 20 enrolled · Massachusetts General Hospital
  NCT06584942updated 2026-01-20

Frequently asked questions

How does Suvorexant work?

The mechanism of action of suvorexant in the treatment of insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system plays a role in wakefulness.

What is Suvorexant used for?

According to FDA labeling, Suvorexant carries indications including: BELSOMRA ® (suvorexant) is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance. BELSOMRA is an orexin receptor antagonist indicated for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance ( 1 ).. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Suvorexant?

Suvorexant is classified as Orexin receptor antagonists, Orexin Receptor Antagonist, Cytochrome P450 3A Inhibitors, Orexin Receptor Antagonists, P-Glycoprotein Inhibitors, Central Nervous System Depression.

What are the brand names for Suvorexant?

Suvorexant is marketed under brand names including Belsomra.

What are the contraindications for Suvorexant?

Suvorexant labeling lists contraindications including: BELSOMRA is contraindicated in patients with narcolepsy. BELSOMRA is contraindicated in patients with narcolepsy ( 4 ).. Always consult the full prescribing information and a clinician.