Melatonergic Drug Ramelteon in Neurotherapeutics

Melatonin, the hormone secreted by the pineal gland, plays an important role in sleep induction and sleep maintenance. With the advancement of age, there is a decline in melatonin production, and elderly individuals often complain difficulties in sleep onset, maintenance of sleep-wake rhythm, and poor quality of sleep. Melatonin replacement therapy has been used for treating insomnias but it is not uniformly successful. With the synthesis of melatonergic agonist, ramelteon, a chronohypnotic drug with a higher affinity for MT1 and MT2 melatonergic receptors, treatment of insomnias has become easy, and many clinical studies have attested the efficacy of ramelteon in treating primary insomnia and secondary insomnias associated with neurodegenerative and neurodevelopmental disorders like autistic disorder. Melatonin has been implicated in the pathogenesis of delirium and autism spectrum disorders (ASD) and has been tried for treatment of these disorders. Although found successful in treating these disorders, melatonergic agonist ramelteon is used for treating autistic disorder and delirium where the drug has been found effective in not only alleviating the sleep disorders but also the behavioral problems. A low or abnormal level of melatonin is suggested as one of the main reasons for the lack of communication skill and socialization which are the main symptoms of ASD. Ramelteon has been used for treating rapid eye movement (REM) sleep behavior disorder (RBD) also and is found to be effective in increasing sleep efficiency and reducing the intensity of behavioral symptoms of this disorder. As a chronohypnotic drug, ramelteon ameliorated the symptoms of jet lag by improving the nighttime sleep efficiency and daytime alertness.