Pharmacology · Other hypnotics (melatonin agonists and orexin antagonists)
Suvorexant !
An orexin receptor antagonist for insomnia. It blocks the brain's wake signal; it can cause next-day drowsiness and brief paralysis on falling asleep.
Updated 2026-11-01
The figure shows suvorexant itself bound to the human OX2 orexin receptor; it also blocks OX1.
Mechanism of action
Orexins are neuropeptides from the hypothalamus that keep the brain awake. Suvorexant blocks orexin 1 and orexin 2 receptors, turning down this wake drive so that sleep can begin and continue, without acting on GABA-A receptors.
- Orexin from the hypothalamus keeps the brain awake
- Suvorexant blocks orexin 1 and 2 receptors
- The wake drive falls: sleep starts and lasts
Pharmacokinetics
- Absorption
- Given by mouth shortly before bed
Indications
- Insomnia: trouble falling or staying asleep Insomnia disorder →
Adverse effects
Common
- Drowsiness and next-day sleepiness
- Headache and dizziness
- Unusual dreams
Contraindications
- Narcolepsy (generally avoided)
- Hypersensitivity to suvorexant
Key interactions
- Alcohol
- Worse side effects; avoided
- Grapefruit and grapefruit juice
- May change its effect; discussed with the prescriber
What is monitored
- Next-day alertness and falls
- Mood and suicidal thoughts
- Episodes of sleep paralysis or sudden leg weakness
Administration and safety
- Given by mouth shortly before bed, only when a full night in bed is possible
- Controlled medicine
Nursing care
- Check how the person slept, next-morning alertness and falls
- Ask about alcohol and other sedatives
- Teach to take it only when a full night in bed is possible and not to drive the next morning if drowsy
- Teach to report sleepwalking, sleep-driving or other actions done while not fully awake
Pregnancy and breastfeeding
Data in pregnancy are limited; plans for pregnancy or breastfeeding are discussed with the prescriber.
Test yourself
Think of the answer, then tap the question to see it.
What does the suffix -orexant indicate?
An orexin receptor antagonist.
Why is suvorexant generally avoided in narcolepsy?
Narcolepsy is linked to orexin loss; blocking orexin further could worsen it.
Which unusual effect on waking can suvorexant cause?
Brief inability to move or speak (sleep paralysis).
Related drugs
Related conditions
← Back to the class: Other hypnotics (melatonin agonists and orexin antagonists)
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Suvorexant: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 22 (McGraw Hill, 2023); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); 4S0V: Crystal structure of the human OX2 orexin receptor bound to the insomnia drug Suvorexant (RCSB Protein Data Bank, 2015).
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Representative model, for educational purposes only.