Current pharmacological treatment of
insomnia involves the use of
sedative-
hypnotic benzodiazepine and non-
benzodiazepine drugs. Although
benzodiazepines improve sleep, their multiple adverse effects hamper their application. Adverse effects include impairment of memory and cognitive functions, next-day hangover and dependence. Non-
benzodiazepines are effective for initiating sleep but are not as effective as
benzodiazepines for improving sleep quality or efficiency. Furthermore, their prolonged use produces adverse effects similar to those observed with
benzodiazepines. Inasmuch as
insomnia may be associated with decreased nocturnal
melatonin, administration of
melatonin is a strategy that has been increasingly used for treating
insomnia.
Melatonin can be effective for improving sleep quality without the adverse effects associated with
hypnotic-
sedatives.
Ramelteon, a synthetic analog of
melatonin which has a longer half life and a stronger affinity for MT1 and MT2 melatonergic receptors, has been reportedly effective for initiating and improving sleep in both adult and elderly insomniacs without showing hangover, dependence, or
cognitive impairment.
Insomnia is also a major complaint among patients suffering from
depressive disorders and is often aggravated by conventional
antidepressants especially the specific
serotonin reuptake inhibitors. The novel
antidepressant agomelatine, a dual action agent with affinity for
melatonin MT1 and MT2 receptors and 5-HT2c antagonistic properties, constitutes a new approach to the treatment of
major depressive disorders.
Agomelatine ameliorates the symptoms of depression and improves the quality and efficiency of sleep. Taken together, the evidence indicates that MT1/
MT2 receptor agonists like
ramelteon or
agomelatine may be valuable pharmacological tools for
insomnia and for depression-associated
insomnia.