Pharmacology · Class
Other hypnotics (melatonin agonists and orexin antagonists) !
Sleep medicines that do not act on GABA: melatonin and ramelteon stimulate melatonin receptors; suvorexant blocks the wake signal orexin.
Updated 2026-11-01
What they are
Two newer groups of hypnotics. Melatonin receptor agonists (melatonin, ramelteon) act on the body clock and help with falling asleep. Orexin receptor antagonists (suvorexant and related drugs) quiet the brain's wake-promoting system.
Mechanism of action
Ramelteon and melatonin stimulate MT1 and MT2 melatonin receptors in the brain's clock. Suvorexant blocks orexin 1 and orexin 2 receptors, so the orexin neuropeptides that keep the brain awake cannot act.
Target: MT1/MT2 melatonin receptors; OX1/OX2 orexin receptors
Drugs in this class
- MelatoninThe body's darkness hormone, taken as a medicine or supplement for jet lag and some sleep-timing problems. Evidence…Melatonin receptor MT1
- RamelteonA melatonin receptor agonist for trouble falling asleep. It does not act on GABA, is not a controlled substance and…Melatonin receptor MT1
- SuvorexantAn orexin receptor antagonist for insomnia. It blocks the brain's wake signal; it can cause next-day drowsiness and…Orexin receptor type 2 (OX2)
Others in the class
- Tasimelteon
- Lemborexant
- Daridorexant
Test yourself
Think of the answer, then tap the question to see it.
Which receptors does ramelteon stimulate?
The MT1 and MT2 melatonin receptors.
How does suvorexant promote sleep?
It blocks orexin 1 and 2 receptors, switching off a wake-promoting signal.
Which antidepressant is contraindicated with ramelteon?
Fluvoxamine, a strong CYP1A2 inhibitor.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - RAMELTEON tablet, film coated (DailyMed (U.S. National Library of Medicine), 2026); 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).
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Representative model, for educational purposes only.