spec sheet12 rows
Suvorexant merck's belsomra; the first fda-approved dual orexin receptor antagonist (2014), a proof-of-concept that blocking the wake signal treats insomnia; effective but its longer half-life makes next-day grogginess more of an issue.
- improves both time to fall asleep and total sleep time versus placebo
- strong sleep-maintenance coverage from the longer half-life
- no rebound insomnia or withdrawal syndrome on stopping, even after a year
- preserves sleep architecture; not a broad sedative like benzodiazepines
- validated over 12 months of continuous nightly use
- headache, dry mouth, abnormal dreams
- rare: sleep paralysis, hypnagogic hallucinations, cataplexy-like weakness, complex sleep behaviors
Overview
the drug that opened the orexin class. it works and it is validated over a full year of use, but the half-life is on the long side (~12 h), so morning sleepiness and next-day driving impairment are the main knocks; the approved doses (10-20 mg) ended up lower than the doses used in the pivotal safety study partly for that reason.
- belsomra was the first genuinely new mechanism approved for insomnia in decades when it launched in 2014; everything before it was essentially gaba-ergic or antihistamine/melatonergic.
- the fda approved lower doses (10-20 mg) than the doses used in some pivotal trials, largely over next-day impairment concerns.
- in the one-year trial, abruptly stopping suvorexant did not cause rebound insomnia or a withdrawal syndrome, a key advantage over benzodiazepines and z-drugs.
- merck ran suvorexant against placebo for a full 12 months, which is unusually long for a hypnotic trial.
Mechanism
suvorexant is a dual receptor ; it competitively and reversibly blocks OX1R and OX2R, the receptors for the wake-promoting peptides orexin-a and orexin-b. reported discovery potency is sub-nanomolar and slightly OX2-weighted (from merck's med-chem program). by damping orexin signaling from the lateral to the brain's arousal centers, it lowers hyperarousal and allows sleep to happen, rather than forcing sedation like -a hypnotics. it largely preserves normal sleep architecture. its pharmacokinetics are the practical differentiator: a longer (~12 hours) than daridorexant means more sleep-maintenance coverage but a higher chance of residual next-morning effects, which drove fda to approve lower doses (10 mg starting, up to 20 mg) than some of the doses studied in the long-term safety trial.
receptor fingerprint
OX2R (-2 / HCRTR2)competitive reversible antagonist
OX1R (-1 / HCRTR1)competitive reversible antagonist
Dosingtypical ranges, not medical advice
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Safetyrisks and cautions, not medical advice
over a year of nightly use suvorexant was generally safe and well tolerated, with somnolence the most common adverse event (about 13% vs 3% on placebo in the 1-year trial, at the higher doses used there) and no rebound insomnia or meaningful withdrawal on abrupt discontinuation (michelson 2014). class cautions apply: next-day driving impairment (the fda specifically warns about it, more so at 20 mg), rare sleep paralysis, hypnagogic/hypnopompic hallucinations, and rare cataplexy-like weakness, plus isolated reports of next-day 'sleep driving'/complex behaviors. it is a schedule iv controlled substance. avoid alcohol and other cns depressants; it is a cyp3a4 substrate so strong cyp3a4 inhibitors raise exposure (use the lowest dose), and it is not recommended in narcolepsy or severe hepatic impairment.
Interactionsdocumented pairs only, not exhaustive
Suvorexant is an orexin receptor antagonist metabolized by CYP3A. Strong CYP3A inhibitors substantially increase suvorexant blood levels; ketoconazole, a potent CYP3A inhibitor, raises suvorexant exposure nearly threefold (area under the curve increases by 179 percent), while diltiazem, a moderate CYP3A inhibitor, approximately doubles suvorexant exposure [3]. This is a pharmacokinetic interaction in which the inhibitor reduces suvorexant's clearance.
Conversely, rifampin, a strong CYP3A inducer, dramatically reduces suvorexant blood levels by 88 percent, potentially rendering lower doses ineffective; this may necessitate dose increases if concomitant enzyme induction cannot be avoided. Orexin antagonists related to suvorexant (such as lemborexant) can also inhibit CYP3A4 through a time-dependent mechanism; concurrent use with drugs heavily dependent on CYP3A metabolism (like clozapine) can lead to elevated concentrations of those drugs and increased side effects [4]. Interactions with most other common medications, antidepressants used off-label for sleep, and benzodiazepines remain largely unstudied.
Checking a whole stack? Run it through interactions + stacks.
History
developed by merck as MK-4305; approved by the fda in august 2014 as belsomra, the first drug in the orexin-antagonist class to reach market. its approval validated a decade-plus of orexin biology (the peptides were discovered in 1998) and paved the way for lemborexant and daridorexant. an earlier merck DORA candidate had failed and the field had watched almorexant flame out in 2011, so suvorexant's approval was a real turning point for the class.
Reputation
respected as the pioneer but somewhat eclipsed by the newer DORAs on the 'clean next morning' axis; clinicians reach for it as a validated non-benzo option, especially for sleep maintenance, but weigh the next-day sedation and driving-impairment warnings. cost and controlled-substance status keep it behind generics as a first choice.
Subjective profileweighing the evidence above
A good choice for people who wake at three in the morning, because orexin blockade holds sleep without the rebound and withdrawal of benzodiazepines and Z-drugs, and it held up over a year of nightly use. The long half-life is the trade; start low and take next-day driving seriously.
Resources
This entry is here for reference.
Research
- 2014first citedSafety and efficacy of suvorexant during 1-year treatment of insomnia with subsequent abrupt tr…
- 2024most recentEffect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction media…
- 1.Safety and efficacy of suvorexant during 1-year treatment of insomnia with subsequent abrupt treatment discontinuation: a phase 3 randomised, double-blind, placebo-controlled trial.
- 2.Orexin Receptor Antagonists in the Treatment of Depression: A Leading Article Summarising Pre-clinical and Clinical Studies.
- 3.Effect of CYP3A Inhibition and Induction on the Pharmacokinetics of Suvorexant: Two Phase I, Open-Label, Fixed-Sequence Trials in Healthy Subjects.
- 4.Effect of lemborexant on pharmacokinetics of clozapine: A potential drug-drug interaction mediated by time-dependent inhibition of CYP3A4.
4 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
why does suvorexant make some people groggy in the morning?
its half-life is around 12 hours, longer than daridorexant's, so more drug is still on board at wake time. that gives good sleep-maintenance coverage but raises the odds of next-morning sleepiness and next-day driving impairment, which is why the fda warns about it and approved lower doses.
is suvorexant addictive?
it is a schedule iv controlled substance, so there is low but real abuse potential. importantly, in the one-year trial it did not cause rebound insomnia or a withdrawal syndrome when stopped abruptly, unlike benzodiazepines and z-drugs.
how is it different from daridorexant and lemborexant?
same class and mechanism (dual orexin block). suvorexant has the longest half-life of the three; that helps with staying asleep but is the main reason it has more next-day baggage. daridorexant is the short-half-life 'clean morning' option and lemborexant sits in between.
can it cause hallucinations or sleep paralysis?
uncommonly, yes. because orexin loss is the biology of narcolepsy, orexin blockers can occasionally produce sleep paralysis, vivid hallucinations while falling asleep or waking, and rare cataplexy-like weakness. these are dose-related and reverse as the drug clears.
what dose should i start at?
the usual starting dose is 10 mg once nightly, increased to a max of 20 mg if needed and tolerated; you should plan for at least 7 hours in bed to reduce morning impairment.
can i take it with other sleep aids or alcohol?
no; stacking cns depressants (alcohol, benzodiazepines, opioids, sedating antihistamines) sharply increases sedation and impairment. also avoid or dose-reduce with strong cyp3a4 inhibitors, which raise suvorexant levels.
does it work for sleep-onset or sleep-maintenance insomnia?
both, but the longer half-life makes it particularly suited to sleep-maintenance (staying asleep through the night); it also shortens time to fall asleep versus placebo.
Adverse effects
- headache, dry mouth, abnormal dreams
- rare: sleep paralysis, hypnagogic hallucinations, cataplexy-like weakness, complex sleep behaviors
Notes and cautions
- next-morning somnolence (dose-related; notable at 20 mg)
- next-day driving impairment (FDA-warned)