Ramelteon, sold under the brand name Rozerem among others, is a sleep agent medication that selectively binds to the MT1 and MT2 receptors in the suprachiasmatic nucleus (SCN), instead of binding to GABAA receptors, such as with drugs like zolpidem.
|Trade names||Rozerem, others|
|Elimination half-life||1–2.6 hours|
|Excretion||Renal (84%) and fecal (4%)|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||259.349 g·mol−1|
|3D model (JSmol)|
A systematic review, published in 2014, concluded "ramelteon was found to be beneficial in preventing delirium in medically ill individuals when compared to placebo."
Six percent of ramelteon-treated patients in clinical trials discontinued due to an adverse event, compared with 2% in the placebo arms. The most frequent adverse events leading to discontinuation were somnolence, dizziness, nausea, fatigue, headache, and insomnia. The United States official Prescribing Information warns of rare cases of anaphylactic reactions, abnormal thinking, and suicide in patients with pre-existing depression.[medical citation needed]
In mice treated with ramelteon for two years, increases in liver and testicular tumors were observed, but only at doses at least 20 times greater than the recommended human dose on a milligram/kilogram basis.
Ramelteon has been evaluated for potential drug interactions with the following medications and showed no significant effects: omeprazole, theophylline, dextromethorphan, and midazolam, digoxin and warfarin. There were no clinically meaningful effects when ramelteon was coadministered with any of these drugs.[medical citation needed]
A drug interaction study showed that there were no clinically meaningful effects or an increase in adverse events when ramelteon and the SSRI Prozac (fluoxetine) were coadministered. When coadministered with ramelteon, fluvoxamine (strong CYP1A2 inhibitor) increased AUC approximately 190-fold, and the Cmax increased approximately 70-fold, compared to ramelteon administered alone. Ramelteon and fluvoxamine should not be coadministered.
Mechanism of actionEdit
Ramelteon is a melatonin receptor agonist with both high affinity for melatonin MT1 and MT2 receptors and selectivity over the MT3 receptor. Ramelteon demonstrates full agonist activity in vitro in cells expressing human MT1 or MT2 receptors, and high selectivity for human MT1 and MT2 receptors compared to the MT3 receptor.
The activity of ramelteon at the MT1 and MT2 receptors is believed to contribute to its sleep-promoting properties, as these receptors, acted upon by endogenous melatonin, are thought to be involved in the maintenance of the circadian rhythm underlying the normal sleep-wake cycle. Ramelteon has no appreciable affinity for the GABA receptor complex or for receptors that bind neuropeptides, cytokines, serotonin, dopamine, noradrenaline, acetylcholine, and opioids. Ramelteon also does not interfere with the activity of a number of selected enzymes in a standard panel.[medical citation needed]
The major metabolite of ramelteon, M-II, is active and has approximately one tenth and one fifth the binding affinity of the parent molecule for the human MT1 and MT2 receptors, respectively, and is 17–25-fold less potent than ramelteon in in vitro functional assays. Although the potency of M-II at MT1 and MT2 receptors is lower than the parent drug, M-II circulates at higher concentrations than the parent producing 20–100-fold greater mean systemic exposure when compared to ramelteon. M-II has weak affinity for the serotonin 5-HT2B receptor, but no appreciable affinity for other receptors or enzymes. Similar to ramelteon, M-II does not interfere with the activity of a number of endogenous enzymes.[medical citation needed]
Ramelteon was approved for use in the United States in July 2005.
- Neubauer DN (February 2008). "A review of ramelteon in the treatment of sleep disorders". Neuropsychiatric Disease and Treatment. 4 (1): 69–79. doi:10.2147/ndt.s483. PMC 2515902. PMID 18728808.
- "Rozerem- ramelteon tablet, film coated". DailyMed. 28 December 2018. Retrieved 13 April 2020.
- Chakraborti D, Tampi DJ, Tampi RR (March 2015). "Melatonin and melatonin agonist for delirium in the elderly patients". American Journal of Alzheimer's Disease and Other Dementias. 30 (2): 119–29. doi:10.1177/1533317514539379. PMID 24946785.
- "Ramelteon Prescribing Information" (PDF). U.S. Food and Drug Administration (FDA).
- Owen RT (April 2006). "Ramelteon: profile of a new sleep-promoting medication". Drugs of Today. 42 (4): 255–63. doi:10.1358/dot.2006.42.4.970842. PMID 16703122.
- "Drug Approval Package: Rozerem (Ramelteon) NDA #021782". U.S. Food and Drug Administration (FDA). 20 October 2005. Retrieved 13 April 2020.
- "Ramelteon". Drug Information Portal. U.S. National Library of Medicine.