Ramelteon
Rozerem
Melatonin Receptor AgonistGeneric available
Ramelteon is a melatonin receptor agonist with high affinity for human MT1 and MT2 receptors with relative selectivity over MT3. Activity at MT1 and MT2 receptors contributes to sleep-promoting properties via maintenance of circadian rhythm and sleep-wake cycle. No appreciable affinity for GABA receptors or other CNS receptors (serotonin, dopamine, noradrenaline, acetylcholine, opiates). Undergoes rapid, high first-pass metabolism with only 1.8% bioavailability despite 84% absorption. Active metabolite M-II circulates at 20-100x higher concentrations than parent drug.
Compare Ramelteon →FDA-Approved Indications
- Insomnia characterized by difficulty with sleep onset (not for sleep maintenance)
Common Off-Label Uses
- Circadian rhythm disorders (shift work, jet lag)
- Delirium prevention in hospitalized elderly (emerging evidence)
- Long-term insomnia (off-label duration — FDA labeled for short-term only)
What Sets This Drug Apart
- ONLY non-scheduled (non-DEA) hypnotic approved for insomnia — no abuse or dependence potential
- Selective MT1/MT2 melatonin agonist targeting circadian sleep-wake regulation — mechanistically distinct from GABA-based hypnotics
- Approved ONLY for sleep-onset insomnia, not sleep maintenance or total sleep time — narrow but specific indication
- Extremely low oral bioavailability (1.8%) despite good absorption due to high first-pass metabolism — high intersubject variability
- Strong CYP1A2 inhibitor fluvoxamine absolutely contraindicated (190-fold AUC increase); requires careful drug interaction screening
- Associated with reproductive hormone effects (decreased testosterone, increased prolactin) — unknown impact on developing reproductive axis