What the label lists and what reports show
Suvorexant side effects
Suvorexant's FDA label: “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 ).” FAERS holds 12,888 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is nightmare (740 reports).
- No generic listed
- DEA Schedule IV
Check it at the source: the suvorexant FDA label on DailyMed (effective March 10, 2025, Merck Sharp & Dohme LLC); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of BELSOMRA?See " What is the most important information I should know about BELSOMRA? " BELSOMRA may cause serious side effects including: worsening depression and suicidal thoughts have happened during treatment with BELSOMRA. Call your healthcare provider right away if you have any worsening depression or thoughts of suicide or dying. complex sleep behaviors such as sleep-walking, sleep-driving, preparing and eating food, making phone calls, having sex or doing other activities while not fully awake that you may not remember the next morning. Call your healthcare provider right away if you experience a complex sleep behavior. temporary inability to move or talk (sleep paralysis) for up to several minutes while you are going to sleep or waking up. temporary weakness in your legs that can happen during the day or at night. […]
Source: FDA drug label, Merck Sharp & Dohme LLC, effective March 10, 2025 (SPL set e5b72731-1acb-45b7-9c13-290ad12d3951), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe 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 ).
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)
| Reaction | Placebo n=767 | BELSOMRA (20 mg in non-elderly or 15 mg in elderly patients) n=493 |
|---|---|---|
| Diarrhea | 1 | 2 |
| Dry mouth | 1 | 2 |
| Upper respiratory tract infection | 1 | 2 |
| Headache | 6 | 7 |
| Somnolence | 3 | 7 |
| Dizziness | 2 | 3 |
| Abnormal dreams | 1 | 2 |
| Cough | 1 | 2 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe 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 ). …
Source: FDA drug label, Merck Sharp & Dohme LLC, effective March 10, 2025 (SPL set e5b72731-1acb-45b7-9c13-290ad12d3951), via openFDA; the full label on DailyMed
What do FAERS reports show?
12,888 reports list suvorexant among the medicines taken, each a report of something that happened, not proof the medicine caused it; 696 are coded as a death and 2,028 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Reports rose sharply in 2016 (2,499, against a median of 714 a year): FAERS counts follow reporting, which news, litigation and label changes can drive, not how often a reaction happens. Of the 17 reactions below, 9 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Suvorexant: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions