RAMELTEON IS A MELATONIN RECEPTOR AGONIST WITH BOTH HIGH AFFINITY FOR MELATONIN MT1 AND MT2 RECEPTORS AND SELECTIVITY OVER 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 OPIATES.
RAMELTEON IS ABSORBED RAPIDLY, WITH MEDIAN PEAK CONCENTRATIONS OCCURRING AT APPROXIMATELY 0.75 HOUR, IS AN ORALLY ACTIVE HYPNOTIC